1999 6.5 stall / No start

[blackonblack]

Hi Everyone,
I am posting this because I am desparate at this point.
I bought my 99 silverado in October last year and it ran fine for a few months. Then this year it started stalling periodically. Then I had a few instances where it wouldn't start. Usually after a bit of time it starts up for no apparant reason. I changed the PMD and relocated as this was mentioned in the forums to be a common cause. It this did not seem to correct the issue. It shut off on a vacation in the middle of a highway and I lost it. I had it towed to a local CHevy dealer and told them I didn't want it back until it was fixed. They found an intermittant ECM communication loss and replaced the ECM. It ran fine for 4 days after that and then stalled on me again and would not restart. I had it taken to my local Chevy dealer and they found a lose connection to the ECM which they repaired. My truck ran find for 5 weeks. I use it every day. No problem. Yesterday I washed it and went to start it up and it would not start. I tried this morning and it would fire and then shut off. I tried a little later and it would fire, and run really ruff and reving really high and then it would shut off. I tried recently and it runs fine. Any suggestions?

[JTodd]

Even though you changed the PMD, it really sounds like that is the problem, especially with no codes. Other than that, start with the more problematic areas first such as the engine grounds.

[Mark Rinker]

Use the search feature here to pour over many similar scenarios. There will be a fairly simple root cause.

Buy Jim Bigley's '6.5 Troubleshooting Guide' - it is a valuable tool and gives many tips and diagnosis for common problems, including stalling.

I would guess you are dealing with bad grounds and/or engine wiring harness issues. The failure after washing is a clue...

[blackonblack]

I have done extensive research on this site and there are so many reasons for this to happen so I'm looking for an educated place to start.

When I went to start my truck again this evening it did not start at first.
Then I left the key forward and the "wait to start" light would cycle on and then off again after a few seconds. I tried again after about 4 cycles and the engine started. But it would rev high and then stutter, rev down and then back up and stutter. After about 30 seconds it evened out and ran smooth. I'm not sure this is an electrical issue but more like there is some component not working right. I don't mind paying to replace parts, I just want to replace most likely suspects first.

Thanks,

Martin

[DA BIG ONE]

I'd check harness behind glove box to ecm. If you look at harness where it comes through firewall you'll find it is exposed to passenger's feet which can and does pull pins out of ecm plugs making for intermittent or no connection to some ecm pins. I've had this problem rear it's ugly head on long trips when the passenger stretches out while sitting with feet forward to firewall and harness. IMHO this is a bad place for a harness to be.

If pins are problem you can simply push them back into their slots w/small thin tool (be careful not to short anything) really bad they will need to be replaced.

[joe bleaux]

It sounds like it could be air in the fuel lines.

Joe