1996 RMW Fuel Gauge

A few weeks I was doing some A/C work on the wagon and I looked down to see the low fuel light on. I put 5 gallons in it and the gauge went up to 3/4 full. Today I took the RMW for a state inspection fuel gauge read around 3/4 full a bit less and after going about 20 mi the gauge suddenly dropped to empty and the low fuel light came on.

Background when I bought the car 10 years ago the fuel gauge worked perfectly, no problems. About 5 years ago the original fuel pump dies and I replaced it with another GM pump and this one did not read the fuel level well at all so I installed the "fuel gauge resistor fix" and it was better but still not like the original pump. This pump with the modification stayed on Full too long and then dropped to empty fairly fast once it started moving, now it seems to drop to empty when it gets to around 3/4 full.

What are my options here? Are the GM or AC Delco pumps still available? If not what pump is everyone using that reads good. Need some advice here. Great driving car but the fuel gauge is the pits.

Bill

I don't think it's your pump causing the problem, it's the sending unit. I have a Caprice wagon with that issue. I did install the resistor fix, which is OK, but not perfect. I reset the trip meter and refill every 300 miles, not really the answer.

I also have a 94 Fleetwood which the gauge does not work either; no resistor fix. I'm pretty sure it's the sending unit also. I also reset the tripmeter and fill up every 300 miles; not ideal, but not anxious to replace the sending units.

Tom

Isn't the sending unit part of the fuel pump?

I don't believe so Bill, I've changed just the fuel pump and I've also changed the complete assembly.

Rock Auto for pictures: https://www.rockauto.com/en/catalog/buick,1994,roadmaster,5.7l+v8,1022151,fuel+&+air

Tom

If you lightly sand the coil of the level sending unit, you may get better results. The other side is that it may be coil is broken. You can check the sending unit with an ohm meter. It should read 0-95 ohms at the extremes.

I've heard that a pencil eraser works well for cleaning the sending unit coils - never tried it myself. If you do sand it, use something like 400 or 600 grit. You're trying to take the oxidation off of wires about the size of a hair.

OK after checking the sending unit is separate from the pump (Thank you) Has anyone tried the Dorman fuel gauge sender for the sedan or wagon? Does it work better than the AC Delco unit?

theamcguy wrote:

OK after checking the sending unit is separate from the pump (Thank you)  Has anyone tried the Dorman fuel gauge sender for the sedan or wagon?  Does it work better than the AC Delco unit?  

I used a Spectra and had a friend with over 100K on a Spectra. I've only got about 10K on mine so far.

One thing of late is if you buy the fuel pump too, the Delphi units have been shipping with an in tank rubber hose that is not rated to be immersed and fails rather quickly. I would swap the original over.

Spectra unit should be fine. Just use caution when installing it because the plastic hose on it is super cheap and easily damaged.

If you get the Delphi unit, which was available cheap through AutoZone be sure and grab a short piece of corrugated fuel line to replace the rubber hose they come with will fail in a couple of days. Trust me.

These cars have very few options when it comes to many repairs and lately the quality of those options is falling rapidly.