Fuel pump fuel guage issues on my '02 B4C

**ANDYZ28** · 11-30-2014, 07:14 AM

I have an '02 B4C (ex VASP) with a fuel gauge the always indicates empty. I figure it is the sender inside the tank. If $$$$ was not an issue I would replace the whole tank unit/module and be done with it. But as $$$$ is an issue, I would like to replace the pump itself as well as the fuel level sender. My question is; which fuel pump to buy? I see that the prices are all over the place and an OE type would be fine with me.

In addition I would prefer to rebuild a spare used tank unit/module, so that once I have the tank out, I can just swap in the rebuilt unit. I will need to find a used one first.

**pajeff02** · 11-30-2014, 02:28 PM

It wouldn't hurt to check the wiring before you pull things apart. I am very happy with the Racetronix unit I installed in our car -- not expensive and very easy to swap out once you remove the tank (or create an access panel). Did the gauge stop working all of a sudden, or was it a gradual demise?

**0rion** · 11-30-2014, 06:12 PM

your first step is to ohm out the sender wires at the plug coming out of the tank....if memory serves me correctly the wires for the sender will be the purple and the black/white wires. The ohms are 40 (empty) - 259 (full). The plug will be on the drivers side just above the rear axle. I would start there first to see if your sender is actually sending the correct ohms. If your gauge is showing empty and your sender is showing like 150 ohms or something (depending on the amount of fuel in the tank) you can rule out the sender as the issue.

**ANDYZ28** · 12-01-2014, 05:07 AM

It was all of a sudden failure. I have still been driving the car, using mileage as a basis when to fuel up. But over time the dead gauge, and "check gauges" light has worn me down.

**ANDYZ28** · 12-01-2014, 05:20 AM

Originally Posted by 0rion

your first step is to ohm out the sender wires at the plug coming out of the tank....if memory serves me correctly the wires for the sender will be the purple and the black/white wires. The ohms are 40 (empty) - 259 (full). The plug will be on the drivers side just above the rear axle. I would start there first to see if your sender is actually sending the correct ohms. If your gauge is showing empty and your sender is showing like 150 ohms or something (depending on the amount of fuel in the tank) you can rule out the sender as the issue.

I will try and OHM the sender today and post the results. Thanks, Andy

**ANDYZ28** · 12-29-2014, 06:07 AM

Pulled the tank out and replaced the in-tank pump with an AC Delco replacement pump. The instruction sheet was for a non LS1 (3rdgen F-body) and I did what I had to do to get the pump to fit/work. The pump was much smaller OD than the one we removed so I put a hose clamp around it to secure it into the black rubber pump holder/isolator. Hey, it worked!

The fuel gauge was a different issue, It was a two fold issue too, the fuel level unit is the tank had quite a bit of wear on the pivot shaft area, and the little electrical contact fingers were worn out to the point where a few of them were actually missing the tips. We replaced it and reinstalled the tank, put fuel in it, started up just fine. But fuel gauge still in operative. We found two broken/damaged wires green (fuel tank pressure sensor) and black w/white stripe (fuel gauge). The green wire was still connected by a single strand of wire, the blk/wht wire was broken in two. After these wires were repaired, the fuel gauge still di not work. I then retested the sender resistance as ORION has suggested, and it was good. I used my Kent-Moore diagnostic electrical terminal connector test set to connect to old sender (which still worked if held just right) to the body harness, fuel gauge still in-op. It appeared to us that someone had probed these two tiny wires at some point in the past and in doing so had damaged them to the point that they eventually failed. I am convinced that the root cause of the gauge failing to operate was the broken wire, but the sender was not going to work for much longer, and the pump and sender would need to be replaced soon. This car had only been worked on by the dealership when it was owned by the Virginia State Police, so that is the only place the wires could have been damaged. They also damaged the connector by cutting of the connector retaining device.

It was getting late and I was forced by circumstance to put the car back together. After the rear axle was reinstalled, and the ABS connecter reconnected and in preparation for bleeding the brakes, we started the car and now the gauge worked! Why it did not work until the ABS connecter was reconnected, is a mystery to me! But is still works and is doing just fine. Thanks for the tip ORION.

Thanks, Andy

**pajeff02** · 12-29-2014, 07:19 AM

Glad you got it all fixed.

**0rion** · 12-29-2014, 10:30 AM

glad you got it fixed. When I had the issue with mine I tore that thing apart front to back. I checked ohms out of the tank, the wiring between the rear plug and pcm, and pcm terminals. I checked everything I could find and everything checked good. I ended up grinding the grounds and putting dialelectric grease on them. Put it back together and it worked. I can't tell you it was a ground issue because I had done them once before with no luck. I just kinda lucked into a fix somewhere but it's been years and years and still going strong. I'd rather be lucky than good.