Fuel guage stuck at 3/4, Need GM techs advice

Tucson_02Silverado · June 24, 2003

Asking for anonymous GM tech help.

Well my first warranty (maybe) item. When the truck is in gear, the fuel guage is at 3/4. When the truck is in P or N the fuel guage starts to erratically move between 1/2 and 3/4. If the engine is off and key to on position same erratic 1/2 to 3/4 movement.

The maybe warrant part is that I have a Denali cluster. I suspect the sending unit in the tank or bad harness. If it was determined that the guage was at fault, what would the average tech do?

1. notice it was Denali cluster and service writer/manager would void warranty claim

2. Just declare that the guage was bad and have it repaired/replaced.

2a. If replacement, would the part number on the cluster be ordered by parts or would parts look up the appropiate part number for order?

3. Anything else?

Thanks

Blue Ghost · June 24, 2003

Well not being your "average tech" so to speak

I would look at the fuel tank level sensor in the tank, i have replaced a ton of these worthless units because they fall apart all the time, plus they should be able to check your cluster operation with the tech 2.

The problem stems from the small metal "fingers" that the sensor uses for contacting the sensor strip, they break off or wear off way to easy.

Hopefully that is your problem and they wont even pay any attention that you have changed the cluster, but i know how some people are.

Best of luck

lowflyer · June 25, 2003

As a former GM tech, I can tell you that it will greatly depend on the person working on the truck. Most will probably not notice the difference and trouble shoot the sending unit first. Find that at fault and just replace it under warranty.

But if someone figures out that the gauge cluster is wrong, they'll stop right there, blame it on the cluster and void the warranty. At that point you will have to pay for a new cluster AND the fix on the sending unit.

Now if they think its the cluster, and its not the same when they pull it from stock, that'll send the red flag up, and you'll end up paying for the sending unit AND new cluster.

Don't bother trying to get the service writer to look the other way, then the tech will make sure to flag it. You see, the tech will make full labor time (ie: more money) if he does the work under repair and not under warranty.

Replace the cluster with the correct one, or borrow someone else's before you take it into the dealership. Sorry and good luck.

96 Vortec · June 25, 2003

Definatly put the stocker back in. If the problem persists, take it to the dealer without worries of warrenty problems.

I had a similar problem on my last truck, I was told by a friend who was a tech at a Chevy dealership that the instrument control module needed to be replaced.

chev_tech · June 25, 2003

Sending unit in tank most likely. Our dealership would warranty no prob. The reason it moves around in P or N is beacause there is a "buffer" that keeps the gauge reading steady, even when bouncing around, braking or accelerating. The buffer is not active in P or N(otherwise your gauge would not show full after a fill up right away if the buffer was active). The sender is almost for sure the fault, but on your cluster question, I know that we can only replace parts that belong on your vehicle, so we could not warranty a cluster that was changed.

Tucson_02Silverado · June 25, 2003

Thanks for the feedback

Putting the stock IPC back in would be a definite red flag. The service writer gets the mileage off the cluster. So if I was in just last week at 15K for tranny syn fluid/filter and rear diff syn fluid, then show up next week at 4200........

I just finished reading the procedure out of the GMT/02 Helms service manual.

So it looks like if the tech does not run the tech2 IPC test first and come up positive, I would have merit for arbitration. Not that I would win, but the claim would then be that the Denali IPC is an aftermarket addon and it would have to be proven that it caused the problem in order to void the vehicles' warranty. Same as a K&N FIPK addon.

Anyways if the P and N is common instance (not stated in manual it is), that would explain the behavior as described in the manual at just key on. At key on that the guage will read the Data2 signal from the PCM last stored fuel level %, which it does - right now just below 1/2 which matches the trip odometer reading zeroed at each tank fill, so much for getting 30MPG. The IPC would not be faulty. The test procedure does lean heavy towards the sender first then connectors second.

I also didn't really word my query right. I meant to put in there that if the Denali IPC was indeed bad that I would pay for the tech2 time and the repair/replacement of Denali IPC out of pocket not try to skate it under warranty.

So I'll make an appointment for next week and arm myself with a copy of the test procedure from the GMT/02 Helms service manual.

Tucson_02Silverado · July 9, 2003

Okay follow up:

Had appointment with dealer today for 0730. Well I had a meeting a 0700 to be told my entire department is without jobs because the services are being outsourced. Anyways get to the dealer at 1000. I let the service writer know that I had a Denali cluster, showed him the problem. He said looks like fuel sender, if it's the cluster but completely doubt it, he would work on trying to get it covered under a Delphi warranty. It was the sender. Call back at 1500 saying the truck was ready. NO CHARGE warranty. So far, many props to Watson Chevrolet in Tucson. I have even gotten hand written thank you cards after my last two visits to service (oil, tranny, rear diff service)