Silent Screamer

Hi guys,

I need your input.

Today I took my 2002 Avalanche for a drive. I purchased this car couple of months ago with a busted fuel pump. Got a new one (Delphi from Rock Auto) an everything was fine until today. I left my car on the parking for about 1.5 hours. When I drove the car back I notice the gauge was actually going slowly UP. After a few miles it started to go down again but then, it went all the way up and says the tank is full. There should be less than half left in the tank...

Anyone has seen that? Before I remove the fuel tank again, if there is anything else that could cause that I'd like to check...

Many thanks in advance for your help.

oldchevy

They had a problem with the stepper motors in the gauge cluster in those years. This could be the cause of the problem. I replaced them myself in an 03 Trailblazer and if you can solder you can do it yourself. The stepper motors are about $25 on Ebay for all 6.

Silent Screamer

Thanks a lot for the quick reply.

I'll give this a look. Any way to see if the fuel level sensor is actually send it nf correct information without removing the tank?

Silent Screamer

Little update:

As I had time today I drained my tank and removed it. Checked my new fuel pump to see if anything was odd with the fuel level sensor unit (sender unit). Everything looked alright so I put the tank back reconnected everything. Surprise, the gauge is now behaving normally... My recent trip was mountain road with long uphills and downhills... I'm wondering if the arm of the gauge could have been stuck..???

Silent Screamer

Hey Guys!

I haven't posted in a while. I have found the origin of my fuel gauge going to full while the tank was near half capacity. Since a while ago I started having evaporative system error codes. When I removed my fuel tank for replacing the fuel pump I also damaged one of the small lines going to the canister next to the fuel tank. I blocked it but I didn't think about it afterwards.

Last time I open my filler cap I noticed there was quite some pressure inside the tank and when I did, my gauge needle instantly returned to where it was supposed to be.

I think that the pressure release solenoid valve that is located right above the rear differential case was to blame. With the hose I cancelled I think it also contributed to pressure building in the tank and for some reason it pushed the fuel gauge sensor up.

Long story short, if your fuel gauge shows full when it should not, try opening your filler cap. if there is pressure there, the solenoid valve might be busted.

I ordered a new set of hose, solenoid valve and clips from Rock Auto. Got it delivered to Japan quick fast but unfortunately, the hose between the solenoid and the canister was too short. There were different references and I probably chose the wrong one so I had to repair the old hose the best way I could. I used a heat gun to removed the new couplers from the hose too short and swapped them on the old one so at least the connectors are new (20 year old plastic isn't the best).

I hope this might help someone else.