2001 Chevy 2500 HD 8.1 still stalling

Hvactech · August 9, 2020

Hello. New here, but read some threads on this topic. I have a 2001 8.1 l in a 2500 HD with Allison. Very randomly stalling. Some times it will loose all power. All gauges stay up, but speed falls and absolutely have no power. It then sputters a little and comes back to life. May not give the problem again for weeks. I have replaced the crank sensor, cam sensor, mass airflow sensor, fuel filter, plugs and wires, with no luck. Will not throw a code. Took it to the dealer last week. They did get it to show its horns once with their computer on it. But did not give any fault codes. He also claims he had a fuel pressure gauge on it, and it did not lose fuel pressure. Everything I read sounds like the above replaced parts fixed the issue. Not my situation. Once in a while it will completely die. Will turn over, but nit fire. A minute or two later it will start and run perfect. Any ideas. Thanks in advance! Note: Truck has 115,000 miles on it, and is flawless mechanically and structurally other than this. Its been pampered.

Edited August 9, 2020 by Hvactech

Formulabruce · August 9, 2020

This will surely sound like a broken record to most in this forum..........

Get some Throttlebody cleaner ( NOt carb cleaner, Actual Throttlebody cleaner)

Remove the air intake and clean the throttle, the plate, BOTH sides and the whole thing inside,

SPOTLESS. Yes Spotless. This has caused this problem on 2 trucks I have owned similar vintage.

I guarantee you have dirt on your plate somewhere or throttle housing. beyond the plate on the bottom.

ps, mine did NOT throw the CE or a code either.

I would use COPPER never seize on the plug threads...

Good luck....

CamGTP · August 9, 2020

When it's very long between problems the throttle blade doesn't seem like it would be it. Those 8.1's are drive by wire too if I remember right so the blade is always open.

These problems are pretty hard to diag when it doesn't happen all the time. Could be the TB itself internally, the pedal assembly or a wiring issue somewhere in the harness.

Hvactech · August 9, 2020

Thank you. I will try it. Formulabruce, will I need a computer/scanner to reprogram the idle position once cleaned, or not a concern on this truck? I read on the models a little newer you have to.

Hvactech · August 9, 2020

Ok.....cleaned throttle body as recommended above. Also replaced the throttling position sensor just to rule it out. Took it for a test run. Same ****** happened. Ran perfect. About 15 minutes into the drive, lost power. The gauges did drop momentarily, dash lights, radio ect...stayed on. While coasting, the truck came back to life without me starting or doing anything, and ran fine for the remainder of the drive. I'm striking out here.

riverbanks · August 9, 2020

Darn,you think it's worth a fuel pressure test of your own?and do you hear pump after stall with key on for the 2 seconds?

Hvactech · August 10, 2020

I ran a fuel pressure gauge up under the wiper cowl to the windshield and drove it for 200 miles over a couple weeks. Never acted up. Took it off and seriously within the first 2 miles it lost power. I'm putting it back on tomorrow. Honestly, I keep going back to fuel, but I don't know. I'm always driving when it loses power, so can't really hear the fuel pump. The few times its actually stalled, I've been in traffic with a horse trailer, so listening for a fuel pump isn't high on my list. I checked all the battery cables and grounds tonight. Pulled up the fuse box and made sure there were no chewed or burned wires ect.. all looks good. Wiggled every wire harness and plug I could find while idling, and could not get it to replicate. Did notice that the wires going to the fuel pump on top of the tank were hot. Not melting or burning hot, but plenty warm. Wondering if a fuel pump can thermal out? Getting to the point of changing the pump. Heck, everything else is new, that might as well be to. Fuel filter is new. If anyone has any more suggestions, i would appreciate it. Thanks