fuel gauge

[kerryw]

y fuel gauge started to act up low fuel light full then empty ,thought it was sender but will do it at all fuel levels ,any sujestions.

[More Power]

A Tech II scan tool can be used to read the fuel level as detected by the truck's ECM. This test would help to eliminate the dash fuel gauge as a potential problem. If the ECM is also sensing an erroneous fuel level, the signal from the fuel tank sensor can be measured using an ohmeter at the underhood electrical center. If you're doing this yourself, let me know, and I can provide the connector location and wire/pinouts.

Jim

[kerryw]

have otc scan unit and also preditor cannot pull any fault codes , filled tank to day sitting with full tank not moving truck gage goes full ,empty also just realised problem started shortly after g.m fixed tow haul switch wire,s in steering assembly. also turn signal warning buzzer if turn signal left on not working could it be related . will check gauge reistance today for sender ,and go from there any help would be apreciated .

[More Power]

http://www.thedieselpageforums.com/photopost/data/500/tanksender.jpg

The above image shows electrical connector C-152, which is located beneath the underhood electrical center.

Pins G (orange/black) & K ( purple) are the tank sender wires. Pin G (orange/black) wire is at 12 o'clock above my thumb, and K (purple) is just off the end of my thumb.

Separate the two halves of C-152, then probe pins G & K with an ohmmeter. You should read something between 250 ohms (completely full tank) and 40 ohms (completely empty tank) if the sender is OK.

Jim

[pslevy]

Hi Jim,

Thanks for the instructions.....

My sender reads approx 3 M Ohms (Hi resistance to open) so its off to seek a new sender. Any pointers?

[More Power]

I'd recommend checking the sender again right at the tank. You might have a wire problem between the tank and the underhood electrical center. The same color wires as indicated above will be present at the tank sender electrical connector.

A replacement tank sender package is about $220 or thereabouts. If you need to replace it, I'd recommend doing a thorough cleaning of the area around where the sender package is located on the fuel tank. Don't want to contaminate the fuel tank with any more dirt & crud than necessary.

Lifting the bed or dropping the tank will be necessary to swap out the sender package. Individual owners (I've) have done it both ways. Dealer service departments drop the tank, but they have a vehicle lift and transmission jack that allows this to be a one-man operation.

Jim

[pslevy]

Hi Jim,

Do you have a picture of the fuel sender?

It seems to me this should be an easy repair if parts are available. I was told I would need to replace the sender and pump because GM packages them togther. So they say I need to replace a good fuel pump is a serious issue for me. Given the mode of failure, (3 M-Ohm) most likely some crude got into the sender. a picture of the device would help ID possable issues.

Thx, Paul.

[More Power]

There is no diesel fuel pump as part of the sender package. That's a gas thing.... :)

The sender is somewhat exposed and easily identified once you get it out.

I don't have a pic.....

Jim

[pslevy]

The dealer said something about the fuel pump and sender replacement.
So your saying its just the sender? the dealer wants $470 for this part!!!!!!!!!!

For a float and a pot????

Spotted a pic.... Looks like the POT is a ceremic thick-film device. Wiper arm seems to be plastic on a metal pivot. Looks to me like it can be cleaned up....

Thoughts?

Regards, Paul.

[More Power]

I priced a Duramax fuel tank sender package at our local GMC dealership a couple of years ago at ~$200. I get a discount, but not $200+ worth.... :D

Jim

[kerryw]

my parts man quoted 600 and change ,reads 370 0hms ,tracking mileage should have 25 litres in tank so reading high ,will drop tank and check it out have also been told tank bafles have come free and move in tank and hang up sender. Service manager ,told me this ,anyone had that happen.

[DouglasMax]

I have the jumpy fuel gauge too. On my '02 Chevy D/A. It does it more when the tank is full. Thank you MorePower for the pick and the ohm values. That is exactly what I was hoping to find on this site.