Is there no GM part number for the potentiometer itself or must one buy the whole shebang just to get a $2(max) potentiometer? I called a local Pontiac dealer and 25027221 (what they said was the sender) sold for over $600. WTF??!! Maybe I'll try a universal one. It wouldn't take that much to make an adapter that would convert any range of ohm sender to any other. If it weren't as simple as just a voltage divider a microcontroller could do it for well under $4, could compensate for the weird shaped tank too.

In that vein, has anyone messed around with keeping track of fuel level with pulse width/time? It is of course a complex solution to a simple problem, but at $600+ for an effing pot, I might have to go a little crazy on it.

 

Yep, they're ridiculous. It's made like a total POS so fixing it is pretty much out of the question. I just replaced my tank and sending unit/pickup rods assembly. Got the stuff from www.rockauto.com A new tank is $175 and a Chinese made sending set from Spectra is $125. A new pump will add another $100 or so to the cost. Toss the pulsator doo-dad and replace with the rubber hose that comes with the pump kit. You'll want to use a new sock too. The Chinese sending unit is made everybit as well as the OEM, handle with extreme care.

Beware that the tank fits great, but the filler neck is misaligned slightly and the factory gas cap basically doesn't fit it. If you're handy with torches you might consider buying the tank without the neck and then soldering the separately available neck with the tank mounted in the car. Pretty much looks to me like how the factory did it.

 

I had a problem with the gas gauge misreading in my 86 2.8 mpfi firebird. I had to do the fuel pump anyway, so i thought i would check out the level sending unit. If you look at the casing for the potentiometer, there will be tabs that hold it to the unit. I bent back the tabs, pulled off the case and looked inside and it was caked with gunk. I cleaned everything out with carb cleaner, and made sure the metal contacted nicely inside. You can also test this by connecting the harness back up with the fuel pump disconnected (keep it from running dry) and move the float up and down while watching the gauge. This is what I did and I could see results on the gauge. Be careful with the metal tabs not to break them when bending them back. If you move the metal housing slightly around before bending the tabs back you can acutally set what is considered empty or full on the gauge. This may or may not work for you, but if it does it will save you a couple hundred bucks. My guess is your problem will be similar. Prices of parts for these are getting rediculous, so sometimes you have to think your way around buying parts

 

Yeah my tank is already out (what a pain that was for what should be a simple job) to replace the stock pump with a Walbro and add the ATI booster pump that I should have put on in the first place. Replaced the pulsator with some high pressure hose which came with the pump. I checked out the inside of the pot as 91chevywt suggested and it wasn't gummed up, but it had some oxidation on the wiper and resistive strip. Cleaned it up a bit, I guess I'll check it out with a multimeter, but if it doesn't work its not worth $125 or even more WoP time. I managed to rip the purple wire off the pot with my beefy mits so I guess I'll have to solder that back on before I can do anything else.