1978 Toyota Pickup 20R-Fuel Pump Relay Replacement/Substitute 

You are most welcome & I'm glad it helped you out. It's nice when the purpose of me posting these things works out. :^)

You're most welcome. I posted this so people could know that you don't have to spend the "stealership" prices for these things. A relay is a relay, as long as it's the right kind. Let me know where you write it up so I can read it too.

RU-vid 78 OF

I'm looking to replace with original parts..do you have a recommendation for 70s Toyota pickup parts.?

@@mrmagoo9901 rockauto stocks a fair amount of parts for these older toyotas.

You are most welcome. I had the same problem so I was determined to post up the info for anyone else looking for it. I had forgotten where I got the image from & it took me a while to find it, but I did. Thank goodness for saving old webpage bookmarks! Here ya go: toyotamotorhome.org/forums/index.php?/topic/6410-1975-electric-fuel-pump-wiring-diagram/ Check the posts from user "zero" to find the diagrams. There are several posts with some extra info & diagrams that should help. If you need any more specific info I'd also be glad to answer any questions or help you out, just let me know. With allthe work & especially study I have been thru on this truck, there isn't a lot left that I don't know. :^)

By the way, the poster "zero" states that the fuel pump resistor is 2.2 Ohms; it is NOT. It is rated at 1.4 Ohms. You might want to test the resistor to see if it's ok. My old one went up to 4 Ohms when hot, causing very little electricity to get to the fuel pump (like 3.4 volts!) causing a very bad idle condition, due to low fuel flow & pressure (fuel starved). Old resistors tend to do that because of getting "heat cycled" underhood so many times. They just don't hold the resistance range anymore. I tested my old one with an Ohm meter & used a hairdryer to heat up the resistor, simulating underhood heat (can get up to 220 degrees F in there!) A new power resistor can be wired/soldered in if you need to replace the original & I have recommendations on that. Let me know if you need the specs or I can point you to a new resistor.

Nice work! Glad that the video has made a positive impact.

You're welcome, glad the video helped.

First, a pretty fair job in trying to narrow the problem down, so well done there. We can eliminate the fuel lines & fuel filter as a possible cause thanks to your test. Also, the test with carb cleaner & it firing right up shows you have good spark & compression. My first guess is that the problem may be related to the electric fuel pump. The 1980 20R normally came with a mechanical fuel pump mounted to the head. Some 20R equipped vehicles (including the Pickup) of other years came with an electric fuel pump mounted inside the gas tank. That system uses the fuel pump relay & a fuel pump resistor. The mechanical fuel pump does not use these parts because, well, it's mechanical & not electric. So your 1980 truck would not have those "factory" parts even installed. I have no idea why a previous owner would put in an electric pump instead. Replacing the mechanical pump is easy. I do not know what electric fuel pump you have on it or what new one you bought. If either or both are the "universal type" that may be your issue. Most "universal" electric pumps are rated for 4 to 7 PSI fuel pressure. The stock carb is designed to operate correctly at 3 to 5 PSI. The universal electric pump could be feeding too much pressure to the carb, causing at worst a flooding condition (way too much gas) or at best minor flooding. This makes the fuel/air mixture going into the engine too rich (too much gas) & if it starts at all it's not going to run right, or may not run at all. The mechanical fuel pump is rated at 5 PSI maximum, so it's matched to the carb's needs by design. What would I do? I'd install the new mechanical fuel pump, hook up all new rubber fuel lines to where they need to go, & also use all new hose clamps where needed. Then test her out & see if she wants to start & run. If you need to know what lines on the mechanical pump go where, check out this thread on Yota Tech: www.yotatech.com/forums/f115/help-mechanical-fuel-pump-109852/ You might also want to pull the valve cover to make sure the eccentric cam that drives the fuel pump is there (also shown on thread). Let me know if you have more questions or what you decide to do.

One other thing. The mechanical pump is supposed to have a spacer between it & the head, & a gasket goes on either side of the spacer (gaskets should have come with your new pump). You didn't say if the old pump is still on the head or not, or was removed & a block-off plate installed. So I don't know if you have the spacer or not. If you don't have it, here's a link to get one: www.rockauto.com/en/catalog/toyota,1980,pickup,2.2l+l4,1277120,fuel+&+air,fuel+pump+spacer,6252 You MUST have the spacer installed for the pump to work correctly.

Here's a link to my original write-up about this on Yotatech: www.yotatech.com/forums/f114/1975-1978-pickup-electric-fuel-pump-wiring-diagram-info-309287/ As long as you get a quality set of a Bosch-style 5 pin relay rated for 30-40 amps plus the socket/pigtail for it, and wire it as described below it will work just like the original relay. Relay terminal to Stock Wire Color 85 - YB - Yellow w/Black Stripe - Oil Pressure Switch 86 - WL - White w/Blue Stripe 30 - BR - Black w/Red Stripe - Fuel Pump 87A - BY - Black w/Yellow Stripe - "RUN" from Ignition Switch, Fuel Pump Resistor 87 - BW - Black w/White Stripe - "START" from Ignition Switch The wire color on the new socket pigtail doesn't matter; you just have to know which one goes to which pin on the relay, and then connect them up properly to the original relay socket in the vehicle. The actual Bosch part number for relay is 0986AH0602. Any other quality brand, 5 pin style of this type of relay is functionally identical. If you search Ebay for "5 pin bosch style relay and socket" you'll find one. BTW, the diagram on the relay itself doesn't have to be exact. I see that the 5 pin relays on Ebay show the coil on the left side and my video & pictures show it on the right side. As long as you get the pin number designations correct & hooked up to the wires as I specified, everything will work just fine. Let me know how it turns out or if you have any other questions.

No, thank you! :^)

I have a link to a 1978 wiring diagram in PDF; here it is: www.globalsoftware-inc.com/coolerman/fj40/schematics/FJ40/1978FJ40/1978_Toyota_LC_Pickup.pdf The '79 should be almost identical, if not very similar. In case you didn't know (& for anyone else out there reading this), that circuit was a safety feature that Toyota designed in for vehicles with carburetors (not EFI). The reasoning for it was that if you got into a crash & the engine stopped, oil pressure would fall off, the oil sender switch would open & de-energize the fuel pump relay, stopping the fuel pump. Nothing worse than being knocked out in a crash & having your electric fuel pump continue to pump fuel thru a ruptured line onto hot metal. incinerating the vehicle & you in the process. I have mine hooked up as stock for that reason, plus if I ever spring an oil leak & oil pressure goes away, it will stop the engine from running with no oil in it. That would be expensive to fix. On later EFI models (22RE), Toyota changed the "signal wire" from the oil pressure switch to the AFM (Air Flow Meter). Here's a diagram of that on Yotatech: www.yotatech.com/forums/f116/no-power-fuel-pump-230687/ Same principle, just a different signal source for the relay. I would think that if you want to run the "idiot light" for oil pressure you could run a wire direct from the sender to the light on the dash, & it would work. Nevermind if you already have an oil pressure gauge. Well done on the EFI conversion sir, that couldn't have been too easy to figure out.

sorry... do you remember which wires ran the pump. I am trying to test the pump at the connection up at the relay.

On the 1975 to 1978 models of the Pickup, there is only one wire that runs to the fuel pump. That wire is Black with a Red stripe. This is the "power" side of the circuit. The other side of the fuel pump circuit is via ground. The fuel pump itself has a ground wire that connects it to the "stalk" that holds it & the fuel level sender. The "stalk is then grounded through the tank itself, which is grounded to the truck's frame, and the frame has a ground cable going from the passenger side motor mount to the battery negative terminal. The only other wire going to the tank area is the wire that goes from the fuel level sender to your gas gauge. That wire should be Yellow with a Red stripe. I'm not sure which "loom" you are referring to but be aware that multi-wire looms can carry wires to several locations or parts of a vehicle. Just because the power wire for the fuel pump is in a loom with other wires, that doesn't mean ALL of the wires in that loom are for the fuel pump. Let me know if you need more info or have other questions.

That depends on which pole in the relay you are talking about. Here's a link to my post about this on Yotatech, that explains it further (& perhaps more clearly) & also includes a stock wiring diagram & instructions. Link: www.yotatech.com/forums/f114/1975-1978-pickup-electric-fuel-pump-wiring-diagram-info-309287/ As you can see by the diagram, the relay is operated by current (or lack of current) from the Oil Pressure Sender Switch. Without oil pressure, that switch is normally closed. That lights up the "OIL" light on the dash, and energizes the coil in the relay to make contact with the "START" pole. Once the engine starts & runs & builds up enough oil pressure, the Oil Pressure Sender Switch opens. This turns off the "OIL" light & the relay's coil de-energizes, allowing the contact to "flop back" to the "RUN" pole. Any other questions just ask.

The basic answer here is, that it should work, despite the parts suppliers saying that it is not compatible. The basis of this is that the relay is electrically the same as the earlier fuel pump relays that are no longer available. They all work exactly the same way, regardless of part number, or whether or not the truck is EFI or has a carb. The "pin" positions in the socket are or should be the same, the coil inside operates the same way and so do the contacts. The main thing is if the socket type is the same; Toyota does have a later relay with a different socket layout that will not fit. It doesn't matter if the truck is EFI or not, there is only a difference in what triggers the action of the coil. Explanation - In carb'ed trucks, the trigger is the oil pressure sender switch. In EFI trucks, the trigger is Air Flow Meter. Both are basically simple switches that either allow current to flow or not. They both work the same way electrically, as far as feeding a signal to the relay. After much research I am 100% sure that the relay is exactly the same inside as the old versions, so logically it should function. I thought I put a comment note saying that I had not tried this myself, so I cannot say 100% that I have personally seen it work. I went with the "Bosch Style" Mod instead, as shown in the video. It was much cheaper, only involved some extra wiring work to solder on the terminals, and after 3 years has been working flawlessly for me. FYI - Even Toyota went tot a Bosch Style Relay after 1995 model years, even for Lexus. I only recommended the newer model Denso relay for those that want to try it out, and have a simple "plug-n-play" replacement.

@@The13thSword After studying the diagram I see it now, thanks again. I went with the Bosch relay.

@@The13thSword Where is the relay located. Is it on the steering column?

@@duderama6750 On the '75 to '78 Pickups, the relay is located under the dashboard, to the passenger side of the steering column basically under the area of the radio. It is mounted by 1 bolt to a flat piece of metal, with the bolt head facing the floor side.

We all have made mistakes along the way when it comes to vehicles, but we can learn from them. I'll try to take your points in order. Yeah, washing out a vehicle interior with a high pressure water hose really isn't the right way to do it. The pressurized water can damage parts & wiring, especially if they are 41 years old, plus the "splash effect" probably sent water up into the fuse box & maybe some other electric components under the dash. Never a good idea, but you work with what you've got. Something else to consider with a vehicle this old is that many parts and systems may need to be rebuilt, replaced or otherwise reworked just to get things working normally again. Time & use takes a toll. If you really want to keep working on this truck as a project, you need to know you may have a LOT of work ahead of you. There could be some basic things wrong or there may be a bunch. I've been through it myself (several times) & it can be a great learning experience. Also understand that it is going to be difficult for me to diagnose your problems "by remote", and also not being able to see things for myself. Just understand that once you get into fixing this truck, you may not be driving it again anytime soon. There are no good quick fixes. The good news though is that when systems are fixed right on these trucks, they respond & work well. Using the high pressure water may or may not have anything to do with your starting & running issues. If you are still able to start the engine & keep it running, even with your foot on the gas pedal, and it runs decent, in general I'd say you probably don't have an electrical problem with the ignition system. The only way to know is to test the entire system for damaged or malfunctioning parts. To learn how to do that you will either need a factory service manual for the specific model & year vehicle. You can buy these at almost any auto parts store and they are the best thing to have when trying to figure out a system. I can also help you a little more by telling you to go to this website & save this link in Favorites: www.retrojdm.com/ScanView.asp?ScanID=104 This is an online version of a factory service manual covering the 20R Engine that should be in your truck. There is a lot of good basic info there that you can learn from, but not all of it may apply to your specific truck. That's why you still need the specific service manual. What you have described does sound like a fuel issue. I wouldn't want to guess but it sounds like the Idle Circuits in the carb are clogged up. It could also be something else like a vacuum leak, a mis-adjusted carb, a worn out carb or something else entirely. Spraying Carb Cleaner "on" the carb may make no difference to how it functions. The problem could be one or several other parts of the fuel system. The 1978 Hilux also has an electrical part to the fuel system, as it has an electric fuel pump in the tank, a fuel pump relay under the dash, and a fuel pump resistor in the engine bay. Any or all of these parts may be so used they just aren't working right anymore, & need to be replaced. There are also a fuel filter (which you mentioned), rubber fuel lines, clamps and even a throttle rod system that connects the gas pedal to the carb. Wear on ANY of these things can cause a start & run issue, so they ALL have to be inspected & gone through. All that leaves me with a bunch of questions about your truck. What's the mileage? Did you have it running OK before all of this? Be specific. Are the engine, transmission & the carb; are they all original parts? What kind of transmission (auto or manual? if manual how many forward speeds, 4 or 5?) Was the truck sitting for a long time not being used before you got it? (Major Issue) What's the condition of the fuel lines? Does the carb look like it's been installed for a long time? Have you been using Ethanol blended gas in it? What one light still works & what other light doesn't? (You are not very clear on this) Why did you need the AAA guy? What happened? Sure, you may need a new alternator eventually because all parts eventually wear out & stop working right, but that doesn't tell me much. Testing the battery with a multimeter is a good idea, but a better idea is take the battery to a parts store & have them test it under load. This is a truer test of the battery's condition, & most parts stores will do this for free. Same goes for the alternator (parts stores will test for free) but testing in the truck it to see if it's charging requires the engine to be running & if you have a hard time keeping it running, you can't test it with a meter. You say it's a dually; most of those were former campers/RV's (or still are). Those have some extra equipment that might make a difference, like extra electrical parts under the hood, a place & wiring for an extra battery, & extra switches in the cab. What have you got? All that is just for starters on info. Once I get a better idea from what answers you can give, I can hopefully give you some ways to go on it.

@@The13thSword The13thSword thank you so much for the thoughtful reply, so the story is that I got this as an RV a couple of months ago and have taken the whole motorhome shell off. I have easy access to the fuel system that way now which hopefully will help me in fixing this problem. AAA came to me because the battery was crap and died while I was driving it home. He put in a new battery. I tested the battery with the car running ( left something on the gas pedal) and it stayed above 13 volts, which I read online means that the alternator is charging the battery. It's a 4 speed manual transmission . Just found out that the fuel line has an external electronic fuel pump connected to the frame outside the gas tank, and there is no fuel filter on the whole system at all. I'm now guessing that since there is no fuel filter the carb is getting absolutely clogged, am I right?

@@The13thSword it has 72,000 miles, ran fine before the only problem it had was overheating. I changed the whole cooling system out and it ran fine for a couple days then it sat for a little while ( 2 weeks ) and I did the washing, now there is this problem, by the way I picked it up for 400$

@@The13thSword also want to say that basically all the parts look like they are old at least 10 - 15 years each. It has all the California emissions stuff and the carb that goes with that setup. Definitely not a weber. The dash lights and gauges all work fine, the headlight turn on.

@@jonahcombs451 You are most welcome & thank you for replying with the extra info, that will make things easier. I see another reply from you & will handle that in turn. You are correct, good alternator charging voltage is usually 13+ volts on up to 14.5 volts, depending on condition of battery, so sounds like the alternator is good. The electric fuel pump on the frame is NOT a stock Toyota item. Since the stock fuel pump is inside the gas tank, when they fail a lot of people just add the external pump like yours has. They don't want to go through the extra work of dropping the tank out of the truck to change the pump out. Any markings on that pump? Make/brand/model number? Some are better than others in quality & durability. Do you still have the stock Toyota carb on the truck or maybe a Weber carb? This can make a big difference concerning the fuel pump. To test the pump & see if it's even working, disconnect the hose on the "engine side" of the pump, put on a short piece of fuel hose, put the loose end in a container to catch any gas, then turn on the ignition (key) for at least 5 seconds. If you get no gas out of it, try cranking the engine for 5 seconds then stop & check the container for gas. If no gas the pump is either dead or the wiring to it has a problem. Any wiring to that pump is also not stock, so we don't know if they did a good job with it or not; it's worth checking out. If the pump is dead you have choices to make. You can either get another external pump of the right type & rating & replace the old one, or you can drop the tank & replace the stock fuel pump inside it. Be advised though that if you do the stock pump, you're going to also have to look at the stock fuel pump relay & resistor. I can guide you through those. The stock fuel filter for this truck is supposed to be located in a round metal clip holder mounted on the passenger side fender skirt, in the engine bay. If there currently isn't one there, they might have just put in a solid length of fuel hose to take it's place. Not a good idea IMO. Again, you are correct (2 in a row!) :^) The lack of a fuel filter will allow small particles of dirt & junk to get to the carb. Most likely the idle passages in the carb are clogged, which is what might be causing your start/run issues. There are some ways to try to clean out the idle passages, but since it was run with no fuel filter, there could be more junk sitting in the fuel bowl, & it just may clog on you again. Also the idle jet (located in the fuel bowl) may be clogged as well. idle jets & passages are VERY small things, & it doesn't take to much junk to clog them up. The idle jet has a hole in it 0.5 mm; this is just twice as thick as a human hair thickness. If you want to try & clean out the carb rather than replacing it let me know & I'll tell you how I do it.

Without more info it's hard to diagnose. It might be fuel, it might not. How much B12 to how much gas? You did add the B12 to the tank right? Fluttering at idle only or when you rev it up or try to drive it also? Have you checked your coolant to see if it is low?

It could be the relay or the resistor. If the relay is original and the truck has a lot of miles, the contacts inside could be worn or pitted, causing a reduced or lack of voltage flow to the pump. There is a resistor for the electric fuel pump as well. As the resistor ages it can develop higher than optimal resistance, also reducing voltage flow to the pump. The resistor can also be fatigued and causing higher resistance when hot. You can test the resistor with an Ohm meter and an electric hair dryer or heat gun. The resistor is located under the hood, on a metal plate on the passenger side wheelwell. If original, it should look like a white cylinder with a wire soldered to each side of it. These wires go to a green plug, which plugs into the wiring harness. Cold, the resistor should measure 1.4 Ohms (original specification). Any reading above 1.54 Ohms or higher the resistor is bad. Leave the Ohm meter hooked up to the resistor and use the hair dryer or heat gun to heat it up, from a distance of 6 inches. Watch the Ohm meter when you do this. If the resistance reading rises above 1.54 Ohms the resistor is bad and needs to be replaced. If that is your case, I have info on hand on how to replace it. Original resistors are no longer available from Toyota but I can recommend a replacement part that will work well. Beyond this, if you check that the relay & resistor are good, then it could be the fuel pump, or a loose or broken connection. If the pumps is original it's more likely to be the pump, since it's over 40 years old. If I can help with any other info let me know.

@@The13thSword hey that is awesome thank you. Yeah I am in love with this little truck and want to make it my daily driver. The fuel pump is original I am trying to find out if I could just install an inline fuel pump to not have to drop the tank to get the OEM one out. Oreilys sold me an in-line pump and stated it was for my truck I told them it was in the tank and they said it was not. Lol

@@scgrindllc Figures. Most parts guys don't know or understand much about older vehicles like ours. That's why I bothered to document all the things I did to my truck & post them to RU-vid, to help out other people like you. :^) Yes, you can install an inline electric fuel pump and leave the old pump in place in the tank, as long as there are no restrictions to fuel flow through the old pump body. This used to be a very common fix for a dead fuel pump in these trucks. Most people just didn't want to go through the bother of draining and lowering the gas tank. I did it because I wanted to keep the original engineering & function, and it let me clean the tank out of 40+ years of junk. New, stock style, in-tank pumps are still available if you decide to go that route though. I used an Airtex E8188 model, but there are others out there. As far as the aftermarket inline pump goes, you just need to be sure that it is rated for 5 to 8 PSI of working (normal running) fuel pressure, as that is the fuel pressure the stock carb needs to work correctly. You would also have to extend the power feed line from the original down to the inline pump, & make sure the new pump is well grounded. That way you would still be using the existing wiring, and not have to do a whole new circuit, which would be very much a bother to do. Most people used to just mount them to the outside of the truck's frame, but as long as it's mounted near the tank it should work. Electric fuel pumps work best when near the tank, "drawing" fuel from it, & pushing it up towards the carb. I do NOT recommend ever mounting an electric fuel pump in the engine bay. Keep me posted on your progress. In the meantime I have to replace the Center Carrier Bearing for the driveshaft on my truck, and may be posting a video on that soon. Cheap $20 bearing part didn't even last 5 years. Lesson learned again by me; buy the best quality parts you can afford.

@@The13thSword Sounds good I will keep you posted . I will also post a little short video of my rig.

@@The13thSword Mr. 13th , I am going to purchase the in tank fuel pump Airtex E8188. Is that the complete system or do I add it to the existing configuration? Just curious to find out if I need anything else to make the swap. Also my gas tank is pretty beat up I saw a video of you changing it. I checked with that yoda part place but they don’t have any tanks . Any other source you might have up your sleeve? If not I might just keep my tank it’s not leaking or cracked just dented . Please let me know and thanks so much.

I have looked through all the previous posts on this video and did not find any from you. Was the previous discussion posts on another video of mine? If yes please let me know which one so I can review the info you posted. Otherwise I'd would need answers to certain questions in order to respond intelligently. I will address a few things you wrote here though. Assuming you have a stock carburetor, the sight glass should NOT show as full. There is a metal plate in front of the sight glass that has two metal tabs on it. The correct fuel level should show somewhere between those two tab. See diagram here: board.marlincrawler.com/index.php?topic=81651.0 It is on the 7th post down. The fuel level in the fuel bowl of the carburetor should be checked with the vehicle on level ground. If your fuel bowl fuel level is "full" the way you describe, the carb is getting too much fuel into it. There could be several causes. 1. Fuel pump installed is not correct and provides too much fuel pressure, flooding the carb. The extra pressure doesn't allow the needle and seat valve in the carb to shut off the fuel flow. What fuel pump did you install? Brand, part number? Is your carb a stock carb or something else? What? 2. Needle & seat valve malfunction. This valve is moved by the float in the fuel bowl. When the fuel level rises, it pushes the float up. When the fuel level gets to a certain point, an arm on the float pushes this valve closed and does not allow the fuel pump to put anymore fuel into the fuel bowl. This is a rare problem, especially on the stock carbs. 3. Float not adjusted properly during rebuild. There is a metal tab on the float that closes the needle & seat valve. If it is out of adjustment, it may not make contact with the needle & seat and not allow the valve to close, which allows too much fuel into the fuel bowl (flooding). Here is the spec for that & other info: www.offroadforum.cz/toyota/aarc.epnet.com/application/8578/8578R05_ADJUSTMENTS.html The Fuel Shutoff Solenoid. Why is it there? It has only one purpose. It shuts off the flow of atomized fuel to your carburetors idle circuit when you turn off the key. This is to prevent the engine from "dieseling" or running on once the ignition circuit is turned off. It should NOT be eliminated. The one wire to it is hooked into your ignition coil power circuit. The solenoid a plunger with a small rubber seal on it's tip. When the ignition is turned off, a spring in the solenoid pushes this plunger forward and blocks off your idle circuit. When you turn the ignition on, the solenoid energizes and retracts the plunger, opening the idle circuit. It is possible that this part is not working correctly, or that the rubber seal is torn or damaged. You can disconnect the wire and remove the solenoid to check the seals condition, and to verify the solenoids operation. You just need to apply battery power to the wire & see if the plunger retracts, then extends once power is removed. I have not been able to find a replacement fuel shutoff solenoid available on the market at the retail level. The only way I could get a new one is to order a fully rebuilt carb from National Carburetor. If the fuel cutoff solenoid is not fully tightened down, it could be the source of a vacuum leak. There is also a small circular gasket that should have been replaced, and usually comes with the carb rebuild kit. Other possible issues. Binding throttle rod linkage. This can affect the idle position of the carb and cause poor idle quality, or cause stumbling issues. Throttle rod linkage wear. On my '78, I had wear to the gas pedal linkage, and still have wear on the rod of the black hinge assembly on the firewall (located straight behind the carb). All this can also throw off the idle position. I have at least one video up about the gas pedal linkage rod, and another one about the rods underhood. At the very least, spray down any & all moving pivot points with WD-40 to lubricate them. If you can point me to your previous info that you posted that will help, otherwise I've got some quesrtions that need answered so I can hopefully point you in the right direction.

Once again thank you for your timely response and your kind attention, just to save time over the years I've had the truck 17 years over the years I've had an issue where the truck shuts off you can be going down the road and it's just like the fuel shuts off, obvious fuel pumps have been changed lines of been cleaned out float float bowl is correct I have done tests using your specs on the coil I've changed igniter gone through every possible thing that could cause this motor to buck and jerk like it's being suddenly electrically shut off or fuel is shut up suddenly, quickly, abruptly hard ,often on much like you're saying here this fuel shut off Solenoid, As a Retired car mechanic and smog mechanic I realize sometimes even on simple cars non computerized I mean, it's a matter of trial-and-error, a badd ground something real basic ,I've covered everything, except this fuel cut off so noyed on the carburetor, Like I said when it shuts off it does it fast like the power is being shut off Only thing on this vehicle I have not dealt with is this Fuel shut up solenoid on the carburetor I feel that this device going on and off quickly could give me my issue It doesn't just starve for gas it just instantly shuts off and bucks in jerks like something inside the carburetor is Shutting the fuel off and on abruptly much like an electrical issue , not electrical issue i covered all of that. Many times when this truck would suddenly start violently jerking I would pull over and the sight glass would be perfect right on the money leading me to believe that if it's starving for fuel suddenly it's not externally out of the carb its Internally, the truck did have issues replaced coil, points ,plugs, condensers, a lots of stuff ,went through the carburetor and this helped it but it still has this sudden I don't know where you never know when it's gonna start doing that again. Do you think there is a relay between the key and the fuel shut off solenoid on the carburetor? It seems to do this the most violently at that cruise position on your gas pedal if I push it all the way to the floor and hold it it'll try to keep going, if I pump it it'll even improve more which leads me to believe that if this fuel solenoid is shutting off the itemized circuit then certainly wide open throttle and pumping the throttle would help it and it does. ROD

@@rodneyyoung385 Glad to try to help. I'll try to take your items in order from the top. Fuel lines - you state they have been cleaned out, but have you ever replaced them? Are you running regular gas in it and are you using the 10% ethanol gas that is common nowadays? I discovered the old rubber fuel lines are NOT formulated to handle ethanol fuels and break down from the inside, shedding tiny rubber particles that can get past your fuel filter and clog up idle passages in the carb. This is what happened to me. I you have not replaced the rubber fuel lines I highly suggest that you do so, with lines that are rated for Ethanol fuels. Iginition - You mention an Igniter but later you mention points. What do you actually have? If you have both I know they did come that way, but there is no accounting for what previous owners may have done. Other thought; if you do have the points system, have you tested your ballast resistor? Once those start to wear out, their resistance can rise with underhood heat, create too much resistance, and effectively shut off power to the coil. It might rad the correct 1.4 to 1.5 Ohms cold, but rise once it gets hot. I had this same problem with my fuel pump resistor, and it's a good idea to check that one as well with an Ohm meter, both cold & hot. Either one hot shouldn't read any more than 10% above spec, 1.54 to 1.65 Ohms. More than that hot and it's bad. Fuel Cutoff Solenoid. It's been my experience that these almost never go "intermittent", they are either working or they aren't. If it is acting intermittent, it's either bad grounding (unlikely since it grounds through the carb itself) or the connector is loose, dirty, corroded, or any combo therof. Again, only way to get a new one is to order a completely rebuilt carb; the part just doesn't exist out there in retail on it's own, I've looked. To the best of my knowledge, there is no relay between the ignition key switch and the fuel cutoff solenoid. It's wired direct into the "hot" side of the ignition circuit. There is a relay for the fuel pump (as you've seen on the video) but your symptoms don't sound like that is the issue. Again, also test the fuel pump resistor. It's underhood on passengers side fenderwell. You say it will do this most violently at cruise position and if you pump it, it will improve. Two things. Does the engine idle normally once up to full operating temp or no? Without any pedal input from you? Second, I've learned that the idle circuit isn't just for idle, but continues to provide fuel above idle speeds, so any blockages in that circuit can have a "lean-out" effect at certain speeds, and could cause "cut-outs", stumbling, etc. Pumping the pedal when this happens is just using the accelerator pump to shoot a bit more gas down the carbs throat to make up for the "missing" fuel. That's why it might be smoothing out. Things I MUST know/have answers to. Has your carb ever been rebuilt since you have had it? If yes, by who and when? Have you done any cleaning to the carb yourself? If yes, give me a complete description of what you have done. Have you checked the bottom butterfly shaft on the carb for play? These carbs have bronze bearings for that shaft, and my old carbs bearing were worn, causing shaft play and a vacuum leak. You can also check for this with the engine running by shooting carb cleaner at each end of the shaft. If the engine speeds up a bit on it's own, you've got leaky shaft bearings. I don't know what level of experience you may or may not have with working on vehicles this old, but I will pass on something here that I have learned. These trucks are over 40 years old, so some of these things you just have to suspect, which ordinarily you wouldn't suspect. So it pays to check every component in a given system or even every piece in a part, without fail. I didn't and it sure gave me an education, but sure cost me a ton of time. Baseline everything.

Great thanks,as usual you have supplied food for thought and some more things to check, too far into this truck to stop now will keep you informed, thanks much, Rod

I assume you mean the part number for the Bosch style relay? Part numbers vary from maker to maker (many companies make it other than Bosch), but the relays are all the same & all work the same way. It is a standard 5 pin Bosch style relay & you can find them from almost any parts store or online for cheap. I went with the one shown from an Ebay seller because it's 75% less cost than a Bosch & has a lifetime warranty to boot. If you need the compatible Bosch part number, the closest I could find is 332209150, Bosch-Tyco 332209150 High Current Mini Relay, SPDT, 40A, 12V. Hope this helps. Let me know if I can do anything else for you.

Same request! I can’t read the part number on the black replacement relay

You could wire in a Bosch style relay like I did & it will likely work, as long as you have the wires connected correctly. I know it will work with the 22R models (carburetor). I haven't tried it on a 22RE (EFI, Electronic Fuel Injection) but looking at the wiring diagram it should work the same. The "off/on" signal for the relay on the carb version comes from the oil sender switch. On EFI models the signal comes from a switch in the Air Flow Meter. As long as the engine is cranking or running it will draw air into the meter, move a flap in the meter that is connected to the switch, and close the switch to complete the circuit. I only did this conversion because the price of the relay for my '78 (IF I could find one) was listed at $80 to $90. I have since found out that the same relay used on later models like your '92 is electrically the exact same thing, and I could have gotten one of those & just plugged it into my existing socket and been done with it. OEM part for your '92 is available all over the web, DENSO Part # 5670045. Original Toyota Part No.: 85910-35010. Average price $35-$40.Dealer Retail on this part is $92.25(!) Just plug "DENSO 5670045" into Google search & you'll find plenty at the better price. DENSO is the OEM parts maker for Toyota so quality is OEM. Let me know if you have any other questions.

Thank you, I found out 78 relay fits but doesn't work on my 92 probably go your method with the Bosh,cause I don't feel like paying 140.00

@@dybalaclint2778 The Denso Part # I gave you before is specific to your year truck, & is only $30 + ship from Rock Auto, and is basically an OEM part. No need to pay the "stealer-ship" prices on those. Link to part on Rock Auto: www.rockauto.com/en/catalog/toyota,1992,pickup,2.4l+l4,1277939,electrical-switch+&+relay,fuel+pump+/+circuit+opening+relay,3380

On the 1975 to 1978 models, the relay is located under the dashboard, to the passenger side of the steering column.

I forgot to mention, it's a 1978 Celica 20R automatic

@@mechanic801 MY description is on the pickup truck, but I imagine it might be near the same place on the Celica. If you still can't find it there, try behind the driver's side kick panel. This is the vertical panel/cover under the dash, to the left of the pedals.

@@The13thSword Thanks, I found it

For most actual Weber branded electric fuel pumps, and some other "aftermarket" pumps that I am aware of, they are all designed to run on full 12 volt battery voltage. So you would no longer need the Fuel Pump Resistor in the circuit. If the resistor was left in the circuit, the Weber pump would only get 9.5 volts in the "RUN" condition, and that might cause you some fuel pressure & volume problems. The resistor could be bypassed at it's harness connector with a jumper wire so that the Weber pump would get full battery voltage in the "RUN" position. I think it would be a good idea to retain the Fuel Pump Relay & you could use the existing fuel pump wiring in the truck's harness to do this. Running all brand new wire to the new pump, I'm uncertain why you'd need a relay. Just use 16 gauge wire & you would be OK. Most electric fuel pumps only draw 3 to 5 amps so they are not a "high draw" item, electrically. 16 gauge wire is good to 20+ amps. IMPORTANT: Depending on the model of Weber or aftermarket pump, and whether or not you are using that pump to supply a Weber carb or a stock Toyota carb, there are some differences that you need to be aware of. I will explain. The stock Toyota carb is designed to run best on 5 to 8 PSI of fuel pressure. The Weber 32/36 carb works best on a fuel pressure of 2 to 3 PSI. So you need to match the pumps specs to whatever carb you are using, ESPECIALLY for a Weber 32/36. They don't like fuel pressures anything above 3 PSI & will easily flood out if that is exceeded. The lowest PSI pump that Weber makes is a 6 PSI pump (Weber Part # 99009.131) so you'd also need a fuel pressure regulator to go in your fuel feed line to the carb IF you're running the Weber 32/36. I'd recommend the Holley #30-804. It's decent quality, within the PSI spec (1-4 PSI), is adjustable & is affordable. IF you're just using the Weber pump to supply the stock Toyota carb, you don't need a fuel pressure regulator. The 6 PSI that pump puts out will be fine for the stock carb.

@@The13thSword i wanted to run new wire & relay incase my truck had a faulty relay or wires, the stock fuel pump im hardly getting 1psi. So truck felt power less on top end. I have a weber 38 on it rn & fall on its face at 3k RPM. I have a fuel pressure regulator, so i just need better fuel pump, i might also run new fuel line incase the stock is clogged or something. The carb doesnt get any fuel, basically it has to be sucked up by covering the carb when cranking. So i think my problem is fuel.. I did found a replacement relay that fit on the stock hilux. That you mention on discriptiom. wanted to try that one, incase the relay on truck doesnt work. But i like the idea of just running a new relay & wires to pump & have less problems. My truck has: 22r/20r hybrid Weber 38 Stage 3 stroker cam *replacing with this LT Headers Cannon intake

@@Mroswaldo16 1 PSI measured or guess-timate? If so, that sounds more like a fuel supply side problem, like a restriction. The stock fuel pumps almost never go "weak" like that; they either work or they don't. It could be corroded or pitted contacts in the relay but I'd have a strong look at the fuel pump resistor first. Test it with an Ohm meter for resistance. The spec is 1.4 Ohms cold, & no more than 1.54 Ohms fully hot. Once those start going bad they develop higher than spec resistance, which could "choke off" voltage to the fuel pump. That could account for the much lowered pump output. You could also have a collapsed fuel line, clogged up fuel filter, the filter sock on the pump itself is clogged, or (this is rare) a bad ground to the fuel pump in-tank. You should also verify that your pressure regulator is working correctly. What brand & part # of regulator do you run? Have you dropped the gas tank and actually had a look at the filter sock & pump? The only reason to run a relay is for safety & function as Toyota designed it to work. Like I said, the stock relay setup "toggles" the voltage going to the pump from the "start" or "run" sides depending on conditions. The stock relay is also dependent on signal/no signal from the oil sender switch. This is the safety side of the circuit. The intent is that in a crash & the engine stops, the no oil pressure signal from the oil sender breaks the circuit to the fuel pump so it doesn't keep running. If this didn't happen, the pump could keep running, & throw raw fuel through broken fuel lines onto hot metals, causing a fire. If you don't care to keep this safety feature it's up to you but be aware that you will lose the safety feature. Your risk.

@@The13thSword 1 psi measured. I installed a fuel pressure regulator. & it bearly read 1psi & its a regulator from lce performance. I might have to pay someone to test that, im not electrical person. I did wanted to check the stock relay see if its corroded.. it did had a new fuel pump. Like 2 years ago.

@@Mroswaldo16 Have you tried adjusting the regulator?

I don't see any reason it wouldn't work. It's the same engine, same fuel pump & same wiring setup as the Pickup. There seems to be a difference in wire colors between the models. I will give you links below to the wiring diagrams. You should also test the fuel pump resistor to make sure it's in spec. The base spec I have for it is 1.4 Ohms. As they get old they can develop higher resistance, which can drop voltage to the pump too much, reducing fuel flow & volume. 1977 Celica Wiring Diagrams (see Figure 5 for the fuel pump relay & wire colors, color chart is in Figure 1): www.autozone.com/repairguides/Toyota-Celica-Supra-1971-1985-Repair-Guide/WIRING-DIAGRAMS/WIRING-DIAGRAMS/_/P-0900c1528007cb61 FOR COMPARISON - Basic Fuel Pump Relay Wiring Diagram 1975-78 Pickup, see 3rd posting, click on third pic in post for larger image: toyotamotorhome.org/forums/index.php?/topic/6410-1975-electric-fuel-pump-wiring-diagram/ If you have any other questions let me know.

The13thSword I saw your update on your description about the denso 5670045 being a plug and play replacement so I opted for that. I just plugged it in and the pump still isn't getting any power. Where would you recommend I look next?

@@hurrdurrilikevideos As far as hard parts you would next test the fuel pump resistor & the pump itself. If the resistor has gone bad (high resistance) it could be keeping voltage from getting to the pump. I am not sure where it is located on the Celica, but on the pickup it's in a steel bracket on the passenger side inner fender well, under the hood. You can see what it looks like here: toyotamotorhome.org/forums/index.php?/topic/6410-1975-electric-fuel-pump-wiring-diagram/ It is the 5th post down, 3rd & 4th picture. The original resistor is ceramic, rated at 1.4 Ohms 10 Watts. Over time & with heat cycling, the resistor can get beyond it's rating in resistance, especially when hot. To test it you'll need an Ohm meter, preferably a self-zeroing meter. Cheap Ohm meters are not self zeroing, so you have to subtract the test leads resistance from the final reading of the resistor. Just set the meter at lowest Ohm setting (usually 200 Ohms) & connect the leads together to see their resistance. Then measure the resistor & subtract lead resistance from that number. You should get no more than 1.6 Ohms reading (10% over), even if the resistor is hot. More than 1.6 Ohms the resistor is bad. I used a hair blow dryer to heat up the resistor to check for this. Also check the wires to it and the connector. Dirt in the connector can also cause extra resistance, or possibly block the flow of voltage entirely. Blasting out the connector with some WD-40 works, just make sure it's dry before reconnecting. My resistor turned up bad, reading 2.6 Ohms hot, that meant only 3.6 Volts were getting to the fuel pump. It's supposed to be about 9.5 volts. Toyota replacement part is no longer available but I have a good fix for this. Contact me if you need to replace the resistor & I'll give you the info on it. Also as a test, you can disconnect the fuel pump resistor & bypass it. You can put a paperclip or short piece of wire in the wire-harness side connector to take the resistors place. WARNING - Only do this for test purposes, just long enough to see/hear if the pump is getting voltage & working. DO NOT DRIVE OR RUN THE VEHICLE LIKE THIS. If you run the fuel pump too long with the bypass you can burn out the pump. If you use the paperclip, make sure it doesn't touch the car body at any time; this will "ground it out" & cause major headaches. FUEL PUMP - If it's old you should consider replacing it. You have to drop the gas tank out of the car to get at it, even to test it directly, so it just makes sense to get a new one in there. Here's the one I used on the Pickup; it's the same one the Celica uses, AIRTEX E8188: www.rockauto.com/en/catalog/toyota,1977,celica,2.2l+l4,1273766,fuel+&+air,fuel+pump,6256 Beyond all that, you can use the Ohm meter to check the actual wiring circuit for continuity and/or voltage. Have you checked your fuses? Any rain leaks on the driver's side near the dash? That can cause problems with the fuse box. Is the fuse box in good shape? Keep at it, it's a 41 year old vehicle that more than likely needs some very overdue attention. It can seem endless sometimes but you just have to follow a logical path on these things; it can be made to work, & work right. Any other questions let me know, I'll do what I can for you.

The13thSword I'll test that next. Do you have a part number for a resistor I could use that would work on it? I looked at my resistor earlier and it's pretty crusty, it probably wouldn't hurt to replace it anyway. I just cleaned up the fuse panel and replaced the fuses this past weekend. The fuse panel seems to be in good condition but I noticed yesterday that now the turn signals don't work but everything else seems to be working fine The fuel pump is new and I just installed it not too long ago. The way I got the car, the fuel pump was spliced into one of the cables to the fuse box and was pretty much on in the car was on the acc/on position. The pump got power like that so I know it works. I'm trying to go back to the original wiring and struggling to get it power.

@@hurrdurrilikevideos Here is the resistor I used to replace the old one: www.mouser.com/ProductDetail/ARCOL-Ohmite/HS10-1R5-F?qs=sGAEpiMZZMtlubZbdhIBIEidPY%252Bx%2FLaa8g707GTTtN8%3D You can order 1 piece from that site. It's Mil-Spec, aluminum cased, moisture proof & can handle whatever heat will be under the hood. I just wired/soldered it into the existing wire harness for it & installed the resistor on the mounting plate like the old one, under the metal hold-down tab. Fuse Panel - My fuse panel had a lot of copper oxide (green stuff) on the terminals on the back, and in the sockets in the plug to it. This caused some electric item to not work; the oxide acted like an insulator. I took the easy way & removed the fuse panel & dipped it in Tarn-X, & also dipped the plug. Took off all the copper oxide & didn't hurt the metal or the plastic. If you do this be careful with the plug, as it could be brittle. Turn Signals - It's either the copper oxide problem or you might need a new turn signal flasher/relay. Original Toyota Part # 9098701001. Nothing listed out there for the '77 but later model ones are the same, like this one: www.rockauto.com/en/moreinfo.php?pk=39373&cc=1273878&jsn=1120&jsn=1120 Your OEM part # is on that listing so it should work. These things didn't change much over the years. Sounds like someone couldn't figure out the relay/resistor circuit, or they had a bad/dirty connection they couldn't find & just wired it direct. Not a good idea, IF they didn't install an inline resistor. The stock style pump was not designed to constantly run on a full 12 volts; it only does that at start up. The stock wiring is set up to give the pump 12 volts when the key is in the "START" position only. This gets a "dry" fuel system primed quicker. Once the engine starts & the key is released to the "ON/ACC" position, the pump is fed voltage through the resistor (about 9 volts). Toyota did this to extend the life of the pump. Running a stock style pump on full 12 volts can burn it out quicker, even if it's a new pump. How long have you been running it with the direct power hookup? I'd do a flow test on the pump to make sure it's still working right. It should be putting out right at a quart every 15 seconds. I'm very interested to hear the results of the resistor test(s); I think that it could be the main suspect here. If the relay is known good, the resistor is known good, & the system is getting power from the fuse box it should work. Only other thing that would keep it from working is a bad ground to the pump or a problem in the power wire itself, but this isn't common. Just don't get frustrated with it, take it a piece at a time in logical order, you'll get it, one way or another.