2001 Suburban 2500

[T Flegel]

I have a 2001 Suburban 2500 LT (200,000 miles) I have owned since new, and I am at my wits end with a fuel gauge issue. 6.0L, auto trans, single fuel tank. The fuel gauge reads accurately, but on occasion, the fuel gauge goes to below empty and the low fuel light comes on. I have replaced the fuel pump/fuel sending unit 3 times in the last 2 years and this problem has never been resolved. Last fuel pump was an after market pump since GM has had problems with their fuel sending units going bad prematurely. I thought there may have been a bad connection since all the manufacturers give you crimp connectors. The last time, I soldered the connections when I changed out the electrical plug to eliminate the possibility of those connections being bad. I also used silicon dielectric compound on the plug in that goes to the top of the pump. I have not removed the gauge cluster nor have I changed the PCM...yet. Any ideas? After changing the last fuel pump, the car only went 1 hour before acting up again. Incidentally, this has been one of the best vehicles I have ever owned...except for this problem. Any help would be greatly appreciated! 

Thank you all in advance.

[Supreme Pizza]

My guess is that its a bad stepper motor. 

 

 

[davester]

Yeah, or possibly something going wrong with the IP circuit board?

 

I would suggest getting a good code reader, one that can access all the computers of the truck, and see what the bcm (well, at least that's the one that manages fuel level for my Sierra) see's as being the fuel level when this happens.  If you do this, you can narrow the problem down to either before the bcm (or possibly the bcm itself), or after the bcm (ie, the instrument panel).

 

A tech ii would be able to show you this, as well as Autogenuity w gm enhancement (and I'm sure other code readers/software solutions).  I think an Edge Insight CTS MIGHT be able to show you this, but I'm not certain.

[T Flegel]

Thank you! That was going to be my next step, and maybe even replace the BCM, because the oil gauge quivers a little all the time. I'm sure all gauges go thru the BCM so I'm leaning towards replacing the BCM. I messed with it a little this afternoon. It acts like a broken wire because the gauge never goes over the correct amount, just under to below empty. I'll keep you posted on what I find since a lot of people have this issue. Oh, on 2001 models, GM used what they call an air core motor and not a stepper motor (which is what I thought at first). Thanks again.