Fuel Gauge Troubleshooting 101 

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Your welcome

Your welcome, just took a break from more filming, we have a rain storm rolling through & it's messing up the audio it's so loud.

Your welcome, we appreciate the comments...keeps us going!

Thanks, your welcome

Thanks for the comments...RonT

Thanks

Thanks

If it's a single wire sender, YES, if it's a 2 or 3 wire sender NO

Your Welcome, hope it helped solve your problem...RonT

@@rontanis1024 It will help when warm weather comes and I can get to working on my hot rod that I have a fuel gauge problem with.

The required resistance values needed are dictated by the gauge they are used with. A few gauges have the ohm range printed on the backside, most you will have to look up in the respective data sheet for the gauge. Our instructions and applications are for the US manufactured recreation boating community, and the standard ohm range for our fuel gauges is 240-33.

It's uncommon to pull a partial float assembly out, which is why we generally remove the tank turn it upside down & shake all the loose parts out.

More than likely the gauge, but I would ground the back of the gauge "S" terminal (pink wire) to the ground and the needle should swing to Max, disconnect the pink wire from the gauge & it should go to E

YES

@@rontanis1024 Thanx!

Yes

@@rontanis1024 Thank you big time!! I replaced the gas Gauge yesterday and all is working! It's a major headache not to know your gas supply!

They are not standard size, you will need to measure the depth of your tank to determine which sender you need. If your bulbs are removable try the local auto parts store for bulbs, fuel hose for marine applications is specific, must have the USCG numbers with E-15 on it for ethanol fuels: skiboatpartsonline.com/Inboard-Ski-Boat-Parts/hose/hose-fuel-3-8.html

All of the US Marine senders I see are 230-33 ohm, (230 empoty-33 full) Europeans use some 33-230 ohm (backwards, and automotive use 0-190 and other scales, Mastercraft uses some variable voltage senders, not variable resistance (they use a 3 wire sender)

Disconnect the pink wire from the back of the gauge & turn the key on, if the gauge swings to Full, gauge is bad, if it stays "E" then reconnect the pink & disconnect the pink at the sender, re-test, if the gauge now pegs over you have a short to ground between the pink wires & ground between the gauge & tank sender.

I am having the same problem. It reads a just over 1/2 a tank when I bought the boat and after I replaced the sending unit with a universal one. Still the same problem.

You didn't say where the float position was but note that there are marine versions and automotive versions of senders & gauges, USA Marine is 33-240 ohms with 33 as full and 240 as empty, european & many auto are reversed from this. Wema makes both.

Senders react & report instantly, a tank that sloshes fuel a lot will cause a sender to do this, many fuel gauges however have electronic circuits that "dampen" the signals to make a more stabil reading. To determine the gauge/sender, remove the sender & while it is wired up move the float up & down & watch the gauge they should work in harmony.

Ron Tanis Thank you, once again. 👍🏼🇨🇦

WHere are you, and where did you get the sender, we sell these but in the American calibration, the European calibration is reverse of the American, sounds like you have a european cal sender for an american gauge.

What kind of boat is this???

The blacks are both grounds, touch a temp. jumper between the pink & ground while someone watches the gauge, if the gauge moves to full when jumped the sender is bad, if not repeat the test at the back of the gauge if it's a conventional gauge, it still nothing the gauge is bad assuming the gauge is getting 12V + at the power terminal & 12V- at the ground terminal.

@@rontanis1024 put jumper from pink to ground and gauge went to full. Pulled sender out and replaced with a reed sender. Wired pink to white on sender, black to black on sender and the other black to mounting bolt on sender, still reading empty. There is power to the purple ignition wire and pink wire on gauge.

@@JB_Machine call me when you have a chance 985-542-4336

No, that means your gauge has electronic "dampening" in it's circuitry - a good thing- stabilize's the gauge reading

Disconnect the pink wire at the sender, turn the key on, if the gauge reads full youi have wireing or gauge issue, now disconnect the pink from the back side of the gauge & turn the key on if the gauge goes to full you have a gauge problem, if the gauge stays still you have a wire issue.

@@rontanis1024 thanks for the help

Tank venting & new EPA tank tank plumbing should not affect a sender, if this is a plastic tank, can you see through the plastic to see the true level, if so, fill it, make note, run till 1/2 full make a note of the gauge, and if reading full with a 1/2 tank report this to the selling dealer as a warranty issue

@@rontanis1024 Hi Ron...I really wish I could see through the tank but not the least bit translusent. And as for going back to the dealer...that's not happening. Don't trust him. The plan is to drive where ever we are going boating and BEFORE I launch open the gas cap and let it vest and see If that solves the problem. Thatvworks after motoring a while so maybe it will work right off the bat. I've tried contacting Crest HQ but they just don't care ...have yet to answer. Not impressed with the company or their reps at all.

YES, we only run into issues with European boats, they run reverse calibrations, and auto applications, these are applicable for all US marine applications.

check the sender

The only way to troubleshoot this is to remove the sender and manually manipulate it and see what the gauge is doing, all the way up should be full. all the way down -empty, half way up -half. If this is a swing arm style you will need to see if the float is hitting something.

You CANNOT use this proceedure for the 3 wire MC senders, traditional. common senders use a variable resistance to ground, the MC sender use a variable voltage usually 1-5 volts, grounding the 3 wire sender will cause damage. You would need to know the senders voltage range to begin working on this.

Remove the sender & move the sender up & down with the key on and watch the gauge, if it is good outside the tank, look for anything preventing the movement inside the tank, if it acts wrong outside the tank, replace the sender. (Assuming you have a std marine fuel gauge in the dash & not an automotive calibrated gauge)

@@rontanis1024 ok Thanks, it’s a standard (original) fuel gauge. It does have a 2014 mercury pro xs 115 on it. If that makes any difference. THANKS FOR YOUR HELP!!

disconnect the pink wire at the fuel tank sender & try it again, if the gauge stays at E now with the switch on you have a bad sender.

@@rontanis1024 awesome, thanks for your reply. I'll give it a try and let you know.

The electrical connections on top of my fuel tank are sealed. Any ideas on how to deal with that?

@@jeffadams4487 If it's a 3 wire sender like MasterCraft uses this video will not apply to that type. If there are 2 wires coming from the sender there must be a wire plug or wire splice near the sender, you would need to break that connection to test the sender.

@@rontanis1024 I wish I could send a photo of my connection but I guess it is not supported. It is a 2 wire connection on a Bennington. My plan is to replace the sensor.

Doubtful, most electronic modern gauges system use variable voltage senders (3 wires) but if it is a 1 or 2 wire sender then yes it would

Reed Switch senders are NOT adjustable, you order the proper length sender. The sender must not touch the bottom of the tank

Reed switch senders are not adjustable, you need to order the correct length for the tank, I like to see 1/4" clearance between the sender and tank bottom.

I measured the resistance on the sender. Ring at the top is about 30 ohms. Ring at the bottom is about 200 ohms.

@@peterjosephsmith7464 33-240 is the std. American Sender values, 200 should show around 1/8 tank, I suspect your gauge is bad.

@@rontanis1024 Thanks for the come-back. Gauge is mounted in a dash. Combined volts and fuel. If I send you a picture can you tell me what new gauge I need? It is 2016 Starcraft Fishmaster..

@@peterjosephsmith7464 Multi-gauges are usually made specifically for a boat builder, and may not be available once the boat builder moves on to another style. Send the pic & I will look at it.

Gauge is 3 3/4 OD, 3 1/4 cutout. #781520PMFB. I found a Teleflex gage that looks similar but number 781480PMFB. I cannot figure how to send a pic here. Let me see about facebook...

Now you need to get a bit more "technical" American Marine fuel senders operate on a 33-240 ohm range, 33 is close to (0) which is what we do when grounding the sender. You will need to use an ohmmeter to measure the resistance from the gauge (disconnected wire) to the tank & back & with a full tank you should see 30-38 ohms resistance, if you do the gauge is bad, if the resistance is around 40-60 with a full tank then you likely have a wire or connection between the gauge & sender that is corroded adding resistance to the circuit. You can also run a temp jumper wire between the gauge & sender. Last possibility is a sender float getting stuck on something preventing it from going all the way up....RonT

@@rontanis1024 Thanks, checked disconnected wire at gauge and it was 60.

re-test at the back of the gauge, with key on run a jumper from a good ground to the pink wire on the back of the gauge, if the gauge responds to Full, then you have a bad wire/connections between the gauge & sender.

@@rontanis1024 thanks for your help

remove the sender from the tank, wire it up & move the swing arm or float up & down while watching the gauge, if the gauge stops at 1/2 then short the pink & black at the sender & the gauge- if it pegs the gauge Full replace the sender, if it sticks at 1/2 replace the gauge.

Your right, the clock & tach are out, a New TRD Gauge kit will be going in soon.

Are you working on a car or boat???

@@rontanis1024 ford 1997 mustang 6 cylinder But in general for ALL cars in 60's, 70s, 80's ,90's how can I test the gauge clusters gauges one by one?

@@rontanis1024 1.) The Temperature gauge needs a "resistance value" or a Voltage? to be applied to the temperature gauge to see the needle moving from C to F? When I disconnect the temperature sending unit/temperature sensor can't I just use a variable resistor potentiometer and watch the temp gauge need moving from C to F? 2.) The Universal Radiator Pressure tester won't test how much pressure the closed loop system PSI level is at while the car is idling and running. I'm looking for a Pressure tester that can test the PSI level while the car is idling and running to know if the PSI pressure level is at normal operating PSI pressure level of the coolant closed loop system. What is the normal operating PSI pressure level on most cars?

@@billwilliams6338 Older cars before engines computers did use variable resistance senders, so yes your variable resistor pot would test these, I have a similar set up for testing marine gauges.

@@rontanis1024 yes the temp sending unit/temp sensor is a thermistor which is a variable resistance But i dont' know what my temperature gauge is wanting a resistance and a voltage or just only a resistance in order to move that temp gauge needle from C to F?

Call me when you get a chance 985-542-4336

Feel free to call me to help diagnose your problem at 985-542-4336

Ron Tanis I’ve done every test, my gauge never leaves 3/4 of the way full, never moves at all. I get 11.5 volts at the gauge, a little low. It’s a multi gauge system from faria that’s discontinued so it doesn’t appear to be an easy swap as I’m not sure they make any the same size any more. Note that it appears non of the gauges work (volt and rpm also but I need to crank it to really check the rpm but it’s too late at night). So I’m pretty darn certain it’s the whole gauge system but would hate it if it wasn’t grounded or something. I changed the sending unit by thebway

Steel ones can but I can't find my aluminum magnate...think my boys borrowed it.

Bad ground at guage