Hey everyone. I have the all too common issue of a non-working fuel gauge, but this issue is a bit more unusual than the standard problems. I had the entire fuel pump replaced less than 2 years/28k ago with a Walbro unit from fuel-pumps.net. A few weeks ago, I would notice that sometimes on startup, the gauge would either be at or snap to the "E" and the Low Fuel light would come on. I would move the truck and it would snap to "F" even if I only had a 1/4 of a tank (I use the fuel used computer). Sometimes it would snap to E when I am driving, but then snap right back to F a few seconds later. If it isn't on F or E, it is right next to "F" and it doesn't get lower. I tried Techron two tanks in a row with no results. For now, it is stuck on F even though I have been using gas like crazy over the past couple weeks, with the occasional time when it hits E. Am I looking at another pump/sender or could this be the gauge cluster?

 

Have you checked for a loose wire or bad connection? I would think if the gauge goes the from E to F that it is a connection or possibility the sending unit. You do know that DELPHI or AC DELCO pumps are highly recommended if you don't want problems?

 

Which connections should I check first? I can't really get to the top of the tank and I want to be sure it is likely the sender before I have the tank dropped.
I realize those brands are highly recommended, but I heard at the time that Walbro is also good and this one was alot cheaper.

EDIT: Which fuse goes to the sender ONLY? I would like to try something to see if it is the cluster.

EDIT2: I found the fuel gauge diag thread. Where is this 6-pin connector? I realize that it goes to the gas tank/fuel pump, but where could I access it? I was thinking of putting resistors of varying resistance on those connectors and checking the fuel readout to check the gauge cluster. Thanks

 

I have the same problem with the fuel gauge. My mechanic (a GM dealership veteran and owner of several GM trucks) says it's the fuel pump sensor after reading the trouble codes off a SnapOn code reader (really cool tablet computer-like unit... it actually gives you the codes and directions in what tests you need to do and what the most likely defective parts are). According to the code reader, the fuel level sensor circuit is "open", which supposedly causes erratic fuel level readings. Most likely culprit: the sensor itself.

You can purchase and change just the sensor (for about $40-80 depending where you buy) and do not need to change the whole fuel pump. Bad news is that the tank will have to come off in order to access it... which is why I'm close to declaring a "FIDO" on it, at least for now (Fvck It, Drive On!).

 

So circuit open shows erratic readings? Mine is only showing completely full and occasionally completely empty. Now never in between. I looked under the car and the only thing I found was a broken ground strap on both ends that has been like that for over a year. I was thinking wiring because it suddenly started happening a few weeks ago. Might be rodents. I might declare this a "FIDO" also if the problem is in the tank, but if the problem is outside the tank, I would like to fix it. Because of the nature of fuel pumps, if I have to have the tank dropped, the pump is getting replaced. How could I be sure without dropping the tank? Is there a place to check the ohms on the gauge sender?

 

I know that the GM service manual has a lengthy procedure on what diagnostics to perform (what to check and what to replace) based on code readings. My mechanic showed it to me, but said that in all likelihood it will be the sensor itself. I told myself that ordering a service manual online (through eBay or whatever) would be a wise choice even if I manage to fix the fuel sensor issue without it, since they seem to contain all the codes and complete diagnostics techniques for each code category.

On another note, I find it stupid how we need to "drop the tank" in order to access the fuel pump. My parents have a 1997 Nissan Pathfinder and the truck has an access door to the fuel pump under one of the retractable rear seats. In essence, you have a small lockable access door in the floor that you can use to test/service/replace the fuel pump without needing so much as a screw driver (it also keeps the top of the fuel pump area very clean, since it's protected from the elements). That is a pretty damn smart idea and I can't figure out why GM and Ford didn't implement it too into their Blazers and Explorers... probably to keep you from doing things yourself, that's why. Because with that access door in the floor, the fuel pump servicing/replacement is 10 minutes tops.

 

I have this same problem with mine, and i have figured out that it is the little sensor that is in the actual tank that reads the fuel level. Unfortuantly the only way that I have found to fix this problem is to get a whole new sending unit. Which is about $400.

 

Then you're getting ripped off... Rockauto has the complete pump assembly for about $200-250 (AC Delco or Delphi). Since you're in the US, you're probably going to get a good deal on shipping too, as opposed to us Canadians who get Rockauto's USPS shipping rates to Mars, apparently.

 

$235 from Amazon shipping included. Got mine from there and installed it last week.

 

I never fix it haha i wasnt going to pay that much for it. Thanks for hooking me up with some good prices though!