Erratic gas guage needle

[DEEPEE]

Posting this for a friend....'01 chevy. Says his gas gauge works fine at times with no flutter and then just simply drop off to the big E. My first thought was a loose ground, but I've heard about instument cluster problems. Anyone run into and cure this before? If it is a ground problem, where should he start looking? Thanks

[slo99sierra]

Going to have to check the plugs at the fuel pump or the fuel level sensor on the pump.

The cluster problems didn't come up in 99-02 models, only 03+ when they changed the cluster.

[j cAT]

Originally Posted by DEEPEE

Posting this for a friend....'01 chevy. Says his gas gauge works fine at times with no flutter and then just simply drop off to the big E. My first thought was a loose ground, but I've heard about instument cluster problems. Anyone run into and cure this before? If it is a ground problem, where should he start looking? Thanks

the sulphur reacts to the silver in the fuel tank sender. this is a common problem ..my 2000 has this also ..I use techron fuel treatment with about 3 oz of marvel mystery oil ..this helps reduce the film that tends to build up on the intank sender reostat..

he just get this truck ? must be ...my truck started this at about 30,ooomiles.........

[muff34]

my 00 will drop to E while on the move. I just slip gear shift into neutral and back into drive and fuel gauge returns to where it should be.

[ukrkoz]

my 00 will drop to E while on the move. I just slip gear shift into neutral and back into drive and fuel gauge returns to where it should be.

mine drops down to E right after refill, then few times after, and stabilizes towards mid tank. but yes, shifting gears does influence it somehow. what in the world shifting gears has to do with gasoline sulfur film have no idea. i just drive it and remember to zero odometer after every refill. screw it, it's one of them GM fuck ups...

[slo99sierra]

It's a load bearing thing. If you put in neutral, the load/demand will drop and the Fuel Pump will send out 68PSI (Key On Engine Off is 66). When put in Drive, the load/demand goes up, the PCM tells the Fuel Pump to crank out say 70PSI because of the increase in load (Transmission)

[j cAT]

Originally Posted by slo99sierra

It's a load bearing thing. If you put in neutral, the load/demand will drop and the Fuel Pump will send out 68PSI (Key On Engine Off is 66). When put in Drive, the load/demand goes up, the PCM tells the Fuel Pump to crank out say 70PSI because of the increase in load (Transmission)

you do not have a correct understanding of how this vehicle fuel system operates.

the fuel pressure is determined by the fuel regulator. this regulator is not controlled by the PCM but by vacuum..no vacuum max pressure.

when starting no vacuum or very low vacuum..

at idle high vacuum regulator reduces pressure slightly to about 53-58 psi.


fuel to the engine is pcm controlled by changing the time the injectors are grounded..the Longer the injectors are commanded to open the longer these are grounded...


On the fuel guage with shifting to drive / to neutral this is where GM does not reveal very clearly whats going on .another secret but the pcm does monitor this fuel tank sender signal and does tweek the injector on time because of it. It may be [I'm guessing] that in drive or neutral the current flow thru the fuel tank sender changes causing the guage to suddenly work for a time ...or maybe not !

[slo99sierra]

I hate having a V6. 64-66psi is what the V6 engines run. The LS V8s run 55-62.