Never Ending Idle Issues in our  

Get your ecu's capacitors replaced. after 30 years the capacitors start leaking and the voltage gets all screwed up. been down this road many times.

I had this fun with my car about a year ago. Changed so much and messed with so much. Can't say for sure but one of the last things I changed was the air temp and coolant temp sensors in the intake. Did a base idle reset and haven't had a problem since. Have my idle at 750. Brew2l a you tube channel has a good base idle reset video.

I would look for a vacuum leak somewhere. That can give fits with your idle.

Bubba i would check also for vacuum leaks and also check your PCV system in the rear. If that doesent fix the issue then inspect the intake for any cracks, usally you can spray brake cleaner around the entire upper and lower manifold. I just put on a holley termintor system and 92 gt getting tuned soon. Just a good hint holley just released the impproved updated terminator for the fox's. Lmr has them

Pull the spout out when tampering with the idle screw and reset the ECU before starting it.

I haven’t seen this suggested in the comments but worth a try. Remove the intake tube ahead of the MAF and clamp the filter directly to the end of the MAF. Having an elbow ahead of the MAF causes erratic airflow through it and therefor erratic readings which will then cause the computer to advance/retard timing like flipping a light switch off/on rapidly and the hunting idle. If you put a timing light on while it’s hunting you can watch the timing fluctuate. That is why the factor MAF had a mesh screen in the inlet, to straighten the airflow through it.

HAD THIS SAME ISSUE. ENDED UP BEING THE IAC. BRAND NEW ONES DID NOT WORK WELL FOR ME. FIND A FORD MOTORCRAFT OR A OE JUNKYARD PART. HOPE THIS HELPS

"If it ain't broke, I haven't tried to fix it yet." LOL!!! I have a shirt that says "Don't worry, I welded it myself."

I bought a actron elite auto scanner. It fits obd1 and obd2.. you can also monitor your vitals with it . Most obd1 scanners you cant. You can also clear codes. Like i said in my other comments. Fix the first codes that come up disconnect battey after the repair. Hook back up then. Resart the process over. The fist code that comes up can cause other codes to come up thats why you fix the first one first. The computer is running in lymp mode at this point thats why nothing your doing is changing anything. I hope this helps not preaching at you i truly hope this fixes this for you...ive been a fox owner for over 30 years at one time had 10 at one time ive seen it all.. i love your channel and been binge watching and like them all hopefully it will help your channel grow..you should be big..you got the right formula. Rock on and keep scrapi fuel injected. 🤘😃🤘

In my honest opinion, first thing id do is send the ECU to ECU exchange, they have the equipment to actually test these ecus, then go from there. Timing is set with the spout connector out and when its put back in, timing will jump, thats ecu controlling the timing advance. But if your timing is jumping with the spout connector out, you may have a timing chain jumping teeth. But have the ecu tested, just because the internal components are clean and look good doesnt mean they are. Get yourself a bit of a understanding of these eec-iv systems before condeming them. Theyre fairly easy systems to understand.

I have the exact same problem. I mean exact same. Same gt 40 sets up with a b cam and it won’t idle without surging unless at 1000 rpm. I’m current in the process of going stand alone with a micro squirt system from efi source. It was really cheap at 475$ for the whole kit. I’ll let you know how that goes but I’m hoping it does the trick. Love how relatable the content is and good luck with your fox 👍

Super Dusty I would check mass air flow sensor

I have an Mass air swapped 88 that is almost identical as far as the idle is concerned but I know its in the main wire harness. You could have a harness issue. Once it finds idle and I can turn on lights and it goes to hell. I am having a harness put in it soon.

clean your iac openings with compressed air lub the iac plunger and plunger o ring remove and clean the carbon from your throttle body

Hey man don't give up on efi yet lol. I've gone through the same crap with my car. I'd double check for vacuum leaks. Pull off any old rubber caps under the plenum and inspect them for cracks or splits. You also need to find out why your timing goes from 12 to 18... 12 should be fine. Oh yeah and I would probably turn the iacv back the way it goes. Good luck and hope you get it figured out.

Check the throttle position sensor voltage using the body as a ground instead of the throttle body. It will give you an incorrect reading. 14 degrees is the highest timing I have been able to run with the same setup on good 93 octane.

Pulling the ECM was a good call. My '94 F-250 had leaky capacitors causing all kinds of problems - mostly making the fuel pump run constantly. The PSOM can also have leaky capacitors, but those usually just mess with automatic transmissions.

I had an 88gt with b303, explorer intake, early c9 heads (heavily ported with bigger valves), 24lb injectors, aftermarket maf (maf swapped since it was originally speed density). I had high idle and surging idle just like this. It turned out to be a combination of problems. I had replaced the iac with an aftermarket one, but they gave me the wrong iac, which caused high idle. Compared to the oem, it looked different. Exchanged it for the correct iac and high idle was fixed. Surging idle was caused by a vacuum leak and dirty maf sensor. As soon as I cleaned the maf, it was perfect.

Also when you pull codes allways fix the first problem first. Then clear codes. The restart.

On my 302 swapped 65 Falcon, I planned to do a carb, but after adding up the cost, I decided to go with an ACES EFI Kit, it included everything I needed besides the intake manifold and I like the options it offers. Similar to the Sniper but IMHO a better product from a smaller US company.

I second the vacuum leak. That's common to cause hunting. The eeciv uses timing more than the iac to control idle. You really need a scope. Also do a KOER test

Spray clean all the sensors. Clean and tighten every ground you can reach. Lightly blowout that computer and wipe the case down, making sure it's firmly tight when rei-nstalling. Is your air filter too dusty? Check alternator connections too. The last 5.0 I worked on had the opposite problem. Wouldn't idle up and with the auto trans, bad. I don't know which of those steps worked, because I did them all at once, one afternoon. I cleaned contacts too on everything I disconnected. The last thing I can think of is a small vacumn leak you may not be able to hear. That's my free internet advice. Now, to cut grass. It's a scorcher already. 9:30 am, 77° at 82% humidity. Might get to 88°. One last thing. My buddy in dallas had a whole house fan. The airflow kept it comfortable and you didn't bust an immediate sweat going out side. A fan thru the roof, on the end away from the swamp cooler might work. What's the temp at the roof ridge, compared to chest height. You'll get it.

Try clocking the maf, or try this part number F2PZ-9F939-A. I had to use one back in the day when I still messed with sbf stuff. I'm pretty sure I've mentioned this in one of your other videos. And get some damn clamps on the couplers 😂 they are very picky about getting unmetered air

Back in the day I was running an fcam along with all of the other goodies in a stock a9l and no tune. Idle and drivability was perfect right from install. I put 100k miles on that car like that and it ran awesome. That same a9l was later fully submerged, with the battery connected, in water during a flood and ended up being fine. These cars are solid and resilient. But with age get finicky. I think you have some bad parts somewhere. Or get a Mega Squirt and tune it out.

Just posted suggesting the TFI. Another thing you can try is to very carefully clean your mass air sensor wire with a q-tip and some electrical contact cleaner or rubbing alcohol. I doubt this will fix your specific problem, but since you live in a very dusty area, it's probably a good idea anyway. I live up North, mine had never been cleaned, and I was surprised how dirty it was.

Join the crowd, it don’t matter what it is , you fix it two days later it’s something else with these cars

Would absolutely love to see a diy paint job on this rig

If I remember back in the day the iac adjuster helped. It sandwiched between the IAC and throttle body. Limiting the duty cycle of the iac helps limit its over all adjustment range. No idea if they are still around

After installing a new throttle body and egr delete, had a surging issue. Prior to the installation I had a high idle that would not come down, even with the idle screw backed all the way out. Ended up being unchecked air coming in that made it impossible to control the idle. The surging was fixed after installing a new TFI module on the distributer, it was going bad and would cause a serious surge until it finally died. Thought it was the new throttle body, ended up being the module and that's after I installed a new ignition coil and plug that broke. Try the TFI module, even if it's new, it can cause the issues you're having

Smoke test to help find the leaks.

when checking the capacitors you can check the bottom. if it isnt flat they are nfg. they also leak as well on the legs. if no leaks thats good. the other thing you may want to check your coolant temp sensor in the black metal tubes. if you unplug it and you see coolant it needs replaced regardless. try to unplug it though and start it and see what happens. unfortunately there isnt a simple answer for surging on these cars. there are multiple things that cause it. mine currently surges only at starup until it warms up a bit then it never does it again. the other issue i have is i have misfires. i have weak spark on 2 posts on the distributor cap. i have an idea what it is but i'll know soon enough. id hold off on the caps though. i havent upgraded my mustang yet as i wanna fix the issues its had first. i did have alot more but alot of them have been fixed. you could also clean the MAF and egr. just because your iac is new doesnt mean its good. the sensors we can buy today are pretty much garbage. if i figure out mine i'll let you know what m,y problem is. i have 0 vac leaks on mine as well. i installed all new lines as mine were dry rotted like hell but somehow not leaking.

There are a few small bolt holes on back of upper intake from original explorer throttle bracket, near where the throttle body bolts up. Easy to miss good luck

Those three blue capacitors are the ones that go bad.

timing stock is 10 12 to 14 is where they usually like it

Edit I have gt40p heads explorer intake E303 cam and it screams if we were back in 1990 but I digress.

Looks like you don’t have a clamp between the mass air and the intake tube. Unmetered air between the mass and engine will give you fits.

I'd do a vacuum smoke test and see if you have any vacuum leaks. I didn't see an EGR valve in the video which is one of the many issues I found with my foxbody. I found several minor leaks it runs so much better.

Could the capacitors be bad on the A9L board? Good luck with the carb swap. I swapped to carb because of the EFI idle surge. Adam at Grover Boys racing posted some good info on doing a carb swap without hacking up the car in case you or a future owner wants to go back to carb. I suggest using the stock 79-85 throttle cable and the stock 85 throttle cable bracket that bolts to the intake. I have not tried the locked timing trick he talks about with the TFI distributor. I am putting a HEI in my son's 90 tomorrow. Previously I used the TFI distributor with MSD box and MSD timing computer, but my MSD died. It is overly complex to go that way too as you have multiple points of failure compared to a HEI. I run a mechanical fuel pump, but you would need to put an eccentric and different timing cover on the motor if you want to go that route. Adam has a neat suggestion for using stock fuel pump with a carb. Adam's video is titled How to carburetor swap a foxbody from efi without "ruining it", the easy way.

Take your fuel sending unit out, turn it over and look at the bottom.... Is one of those rivets rusted? That's your ground wire. It's a ford, it's always the ground wire. The only difference between premium unleaded, and regular unleaded, is water content. And that water content, in your gasoline..... No rots out the rivets tell the fuel sending unit. Also.... Ford is plagued by a ton of counterfeit parts in the market. Don't get no electronics from autozone, don't get no electronics from O'Reilly's. Those are garbage. Ain't nobody trying to counterfeit any Standard brand parts. Thunder counterfeiting everything from spark plugs, to timing chains. Ford motor company sat down in front of congress, under the Obama administration. And asked them to do something about it. Under the advised of, our brilliant politicians. Their solution was simple.... Just raise the price of your cars.

Put a Holley Sniper 2 on it!

Just a suggestion....being as yer in the AZ desert as am I you might wanna check for critter damage

Ive also seen these work but i didnt need one on my car F2PZ-9F939-A

Basically have the same setup except running a E303 can and my problem was the distributor. Also the Informous Project and Mike Murillo i do believe are based out of Texas. Could be good resources for information.

18° base timing is too high, most cars run best at 14° base on 93 (+/-1°). Stock is about 10° base. Try to blip the throttle after start-up to barely above 1500 rpm and it should idle down smoothly. Seems to figure itself out after it can stabilize >1500 rpm. Use some spray to check for vacuum leaks. Brew2l has a good base idle reset video, if needed. GL How large is your TB? Have heard that large TB occasionally need an 1/8" hole drilled in blade of TB (>70mm) to aid idle (small blade adjustments are still too large).

I was have the same problem and it was the ect sender on the heater tube that was bad put a new one on and soo far so good after a week of driving it

For me, it's never been the computer, but you've already ruled that out. Vacuum leaks can cause this, but if you've connected/installed everything correctly, why would you have one? Over the years I've had drivability and idling issues always come down to one thing. Drum roll - the TFI module. I've replaced at least 3 of these. They're mounted to the distributor, which gets really hot, and they develop problems. The last time I bought a new TFI, I made a homemade heatsink and relocated the TFI off the distributor. I haven't had any problems since. The price of a TFI varies wildly. Currently I see one on Am... for $48 Standard Motor Products LX218T. Q: did the problem start after doing the swap, or was it there before? Those parts shouldn't cause a problem, so I'd give the TFI a shot.

If i recall correctly i had to find a balance with tps voltage to how much i had the thrpttle blade opened where it was happy, i dont think setting the tps by the voltage it was supposed to be worked very good

Definitely check the maf. If not the problem just sell me the fuel injection stuff I need it😬

Idling is overrated anyway. WOT FTW.

Try changing the MAF it usually fix higher idles I would also check the Map, oxygen, act, IAT sensors. After that, I'm not sure. I was having a similar issue with my 5.0 '93 Thunderbird, I put her up for about a year, but I'm about to dive back in with all the above mentioned sensors new and a NOS wiring harness for the engine, hoping it solves my idle woes.

Base idle reset is BS, you did everything you can with what you have so, a few choices, carb it? What I did was install a Bama 4 bank eliminator chip which works great for me…I have videos on that or Holley X. Bama the cheapest option and it works great, I’ve been running it for about 2 years now. But, carb swap may be the best long term solution? I’m not won over with Holley terminator, that could be a pita overtime? Idk, I only have limited experience with Holley and so far, I’m not thrilled with it! Carb, never gives same problems over and over again. Look forward to you next move on the mustang.

Maybe Mr. Cool will sponsor you for a min-split A/C unit like they did Tony Angelo.

Ditch the 30yr old computer and put a Holley system on it

High timing doesn't mean max hp, 18 is too much in my opinion. Have you done a complete base idle reset? Do you KNOW the outer part hb hasn't spun? Idle needs to be set with IAC unplugged, then switch car off, plug in IAC and run for 2 min.

So crazy thing. My car did the same exact thing. Wouldn’t idle for nothing. Sometimes surged so bad it would kill itself. I continued to drive it. One day. It just stopped. No rhyme. No reason. Had no clue what happened.

on my 95 f150 it was the cam paired with an untuned ecu and it would be the map sensor crying about all that because I read somewhere it's based on something like 90% efficiency

I'm Old school.. So.. (Girl) I had Bias ply on a Jeep in '91 when I moved to Alaska, not fun, even in 4X4, so had to run chains. That computer looked like an old 8 track😅. Someone said "Vacuum?"

Check for a vacuum leak, probably on lower intake that’s what your problem might be

Buy a smoke machine, you can use it finding exhaust leaks too

Back in the day guys would drill a 1/8" hole in the throttle body's disc. Is there a good rubber hose connected to the MAP sensor? But I still say you should locate the Ford part number I commented on your last video about Scappy's idle.

Carb it or try aftermarket EFI.

Take off all that old fuel injection setup and get a Holley Sniper 2 fuel injection kit

Try changing the mass air flow sensor

Just on some of the experiences I've had my 93 would not run correctly unless the TPS was at point 87, it didn't like anything. Higher than that and all of them r different.

MAP sensor?? My friend had a mustang that did the same thing and I'm not sure he ever got it resolved..... Good luck

I mentioned it in your other video on this, rotate your mass air meter bro. Try rotating it 180 or 90

After market intake tube restricting the air flow around the mass air flow

What about a tune bro maybe a dyno I'm not sure myself mine does it at first start but evens out pretty quick hate to see you have to carb it but I understand for sure!!

Just put a carb on it

I opened up the IAC ports on the intake and that helped a ton on my ported gt40p/ gt40 intake Bcam 1.7rr set up, I tried everything from timing adjustments tps adjustments replaced all sensors but this modification did the most good. I still have cold start surging but I may open it up more since that seemed to help a ton, I started out opening it up a 1/8” with a carbide bur, give it a try! According to ancient online forums it’s a old school trick

Did you try asking fitech or aces yet?

Have you tried to pull the codes???? Your light on the dash is on ,that means computer is trying to tell you whats wrong. In theory...lol.

Base idle reset.

The stock computer does not like low vacuum signal. The cam may be “small”, but the LSA is 112 degrees and that typically is enough to drop idle vacuum. I’d be looking for a cam with something with a 114 LSA. I think the stock cam has a 116. I’ve looked at alot of cam grinds, and once you really start paying attention, none of the available cams are really much different from each other. You realize the lifts/grinds are similar. You increase duration, LSA goes down, lifts are affected by rocker arm ratio, etc… I don’t know if the real issue is it’s hard to grind a cam that snaps the valves open fast enough that allow you to spread the lobes to get the LSA at that higher number, but keep higher duration numbers, or if cam manufacturers don’t want to because they think what they sell is “good enough”. Of course, these are all thoughts I have without ever grinding a cam, so I don’t know what limitations there are. Maybe it could be done, but you’d need way better valve springs. Maybe the math don’t math in reality. Anyway, I think unless you can figure out a way to trick the computer into seeing more vacuum at idle, you’re options are pull it all and put a carb on it, chip the stock computer, or go with a Holley stand alone

I’m still sticking with my original comment. Put a carb on it. I had an “83” with the factory 4 barrel. It was fun after changing the gears from 293 to 345s

Please don't ruin the car by putting a junk carb on it. Find a Moates QH, get Binary editor, and have it tuned. Watch the Leech Motorsports videos on tuning and you will understand what the computer wants to see to stabilize idle. My combo is way more radical than that, and it idles fine under 800rpm. Please, please don't carb swap it.

A LS will fix the idle. LOL

Electric fans? I didn't see you donthe full base idle reset

Could just need an LS and all would be fixed

Also when you pull codes allways fix the first problem first. Then clear codes. The restart.