'01 fuel sending unit suspect....

[chessy56]

I suspect I have a flaky fuel sending unit in my '01 2500HD. My gauge will move from whatever level I have in the tank to Empty and back, even after refueling my truck. I've seen several posts on the internet suggesting removal of the box is best, while others say drop the tank. Given that I'd be doing this myself (without help), what preference would you guys have: drop the tank or pull the box? Also, is it difficult to remove the plastic retainers on the fuel lines and is there enough wire harness to allow dropping the tank?

Anybody?

2001 Silverado 2500HD
Dmax, 265K miles

[DmaxMaverick]

Lift the bed, without a doubt. You'll have full view and access to the top of the tank, plumbing and harness. Dropping the tank allows much less access, and risks damaging plumbing and wires. You can "test drive" with the bed removed, but can't with the tank out. If you have a good plan, removing the bed is easier and quicker than the tank. I used T-posts and motorcycle straps to suspend a bed once, single handed (urgent necessity). Garage rafters or similar are more practical.

[chessy56]

Thanks Maverick- Sounds like this is more practical than draining/balancing a tank. I should be able to inspect other harnesses and install a lift pump as well at this time!

[DmaxMaverick]

Good luck, and try to keep it as simple as it is. The LP is still under the cab. You aren't going to lift that off too, are you?

[chessy56]

I think I'll stop at lifting the bed! I don't have a LP in the system now; was looking at picking up something along the lines that Kennedy sells. I thought I should be able to install the LP somewhere in the vicinity of the cooler ahead of the tank. I envisioned having easier access to the hose between the tank/cooler with the bed off- maybe I'm looking at things wrong.

I occasionally have to get out and hand-prime the fuel system if the engine won't fire up, usually in colder climates or if parked with my nose up hill. I've replaced the filter/head assm'y once before ($500 from the local dealership!). The LP should help keep the line primed....
Thanks.

[DmaxMaverick]

Oops. got mixed up on the models. correct....no OEM lift pump. Adding one is a good idea, though.

[chessy56]

Further information: I put an Edge CTS monitor on my truck and noticed that the fuel level PID information does NOT drop whenever the fuel gauge drops (and, the low fuel message is displayed). From this, I can assume that either the Edge or PID information is faulty or, the fuel sending unit IS properly functioning and the problem lies somewhere between the PCM and the instrument cluster. Anyone have any thoughts on where to look next? Thanks.