[74gto]

Fuel gauge on my wifes' Envoy goes straight to empty when started. Sometimes it will clinb to the proper fuel level, but within a minute it will go down to empty and turn on the warning light. My dads' 2001 Silverado does the same thing, but sometimes starts working on it's own. Any ideas?? is this a common problem on the newer generation of GM trucks?? Thanks, JOHN

[John V.]

'97 Safari Fuel Gauge started working erratlically after about 4 years or so. Then stopped altogether shortly thereafter. But ours always read full. Actually it would drop maybe a 1/16 to an 1/8 as the tank ran to empty. We used trip odometer to judge fuel level for several years.

Don't know if the newer trucks are same design but in '97 the fuel level signal was basically a float and rheostat that was part of the Fuel Pump assembly.

The "pointer" on the rheostat would wear down and no more variable resistance signal. I believe high resistance signaled full tank so that is what ours always read.

Finally last year, the fuel pump died. New fuel pump includes new fuel level rheostat so gauge is working like new again.

Ours also always swung to empty (normal) when started and every once in awhile took a little while before it would climb to reading full giving me the false hope that it would start working again on rare occasions.

Since yours reads just the opposite, perhaps it is a different problem altogether. Or maybe GM reversed the gauge so that full resistance now reads empty?

There is a ground near the tank that is also the source of false gauge readings. Mine was clean, no corrosion, but I did disconnect it and reconnect it to see if that would cure my problem.

There is also some sort of unit under the dash that was another potential cause of false fuel readings on the Safari (I have the Shop Manual and there is a full diagnostic provided). I never got around to checking that unit on mine so I don't know much about it.

I always knew my problem was likely the sender/fuel pump and I wasn't about to pay to replace a good fuel pump just to get the gauge working. But as you might know, it is a LOT more convenient to have a working gauge.

From what I gathered, this was a very common problem for GMs of my vintage. But I really don't know if it applies to the newer ones.