'98 Jimmy fuel gauge issue
 

Hi, I'm new to this forum...seems more activity around here than at others.

Recently we bought a '98 Jimmy. About a month after we had it the original fuel pump quit. Up until this point the gauge had worked perfectly. We had the pump replaced and with the needle in the red on E the tank (18 gallons capacity) only took 13 gallons. I figured it was a new sending unit and the float had to register correctly or was stuck after pulling the tank and replacing the unit. After driving a couple days the gauge was again down to 1/4 tank. This time only filling up took 8 gallons. We then took the truck back to the shop, had them replace the sending unit with a new one. They tested it and drove it adding 5 gallons of gas at a time and watching the gauge. Now the same issue is happening again with the gauge. The check gauges light will come on and the needle will be on E but the tank will only take 13 or so gallons. Has anyone else had this issue before? Seems it would be sending unit related since a bad ground would cause the pump to be weak or not run and the gauge would be all over the place.

Thanks!

Well tonight I crawled under the truck to see if I can see anything. No luck but I could feel up on top of sending unit and wiggled the connections around. One plug is solid but the other plug is very loose. The connection is good but where it is mounted on the sending unit it loose. Anyone else run into this? Now and then I can smell gas too after driving but never any wet spots or leaks. Also the overhead display said that 6 gallons were used after filling and the needle showed 1/2 tank. I hate to pull the tank and put in third sending unit... anything else I should check that is common issue?

What brand of fuel pump assembly are you installing? DON'T waste your money on a cheapy unit from a box store like Auto-Zone, Advance etc... Hopefully you are installing an AC Delco or Delphi unit. Air-Tex is supposedly an OEM quality replacement but I have even had trouble with those.
When you install the new unit... pay special attention to make sure that it is "cocked" correctly so that the float arm is able to travel through it's full range of motion. This is a more common mistake than people realize.
Also be sure and use quality wire crimps with the new supplied pump harness.
Good luck!

I haven't replaced the unit yet...still wondering if I should take it back to the shop and make them fix it again under warranty. If I do replace it, I will put a Delco or Delphi in. I always try to use GM parts when I can. I've used Airtex before with good results too. I was just hoping it was something easier than another fuel sending unit.