No start condition - turns over but does not run

[ericward]

We have a no start condition on a 2000 Hummer but this thread should apply to at least 96-03 turbo diesel trucks and some things apply to others as well.

Of course the #1 cause for a no start condition where the motor turns over all day btu won't start is a bad PMD or FSD (those are the same thing) but we have replaced it several times already and that's not it in this case. This may turn into THE most comprehensive "no start" thread on the internet for Hummer H1's.

The back story:
Drove this Hummer up onto a trailer, it ran fine. When I got to the destination (5 miles from here) it wouldn't start.
- Replaced the PMD, no change
- Replaced the PMD extension harness, no change. This has been an issue we had seen in the past though so always worth checking.
- Verified we have proper fuel flow and pressure (10psi) in the system with an in-line pressure tester after the fuel lift pump.
- Verified the FSS (fuel shutoff solenoid) is functioning properly by removing it and reconnecting the electrical and verifying it opens and closes when the key is turned on and off.
- Verified all the electrical is correct at the PMD to communicate to the IP (injection pump). Everything is normal and the IP "should" work but will not.
- Cracked all the fuel injection lines and verified no fuel was coming from any of them. We do have fuel up to the IP but since it is not passing through the IP into the engine we though the IP was defective and we replaced it. Fucking problem is that still didn't work.

Any other suggestions of what to do would be appreciated. We see no start conditions ALL the time and we have gone through all the regular motions (many of them several times) and it still won't run.

[ericward]

Here's some more tech info:



Electrical wise, here's what's up. Since there is no pin out in the service book or that I could find assume all connectors are "pined out" from left to right then top to bottom with the clip up.
6-pin connector on IP: (key on)
G - 4.5v - G
3.3V - 3.3v - 5.0v

PMD: (with key on) (no aftermarket resistor in the PMD BTW)
G - 3.7 - 12 - G - G - G
PMD: (while turning the motor over)
G - 3.9 - 12 - G - G - G

FSS: (key on)
G - 12v

The other 4-pin connector on the IP that drives the solenoid:
G - 10.8 - G - 10.8

[Gadgetmason]

Just had this with my 1996. Was the glow plug controller for me. Had PMD faults too, but you accomplished the necessary checks there.

[Gunshow]

I occasionally have this issue with my 2001. I know I'm about to have a no start issue when I get NO wait light when I turn the key. The motor will crank and crank with no start. I do notice that the lift pump doesn't activate when I have a no wait light also. I'll open the hood and wiggle the Glow Plug Controller connections around and that fixes the issue.

Eric, I would make sure the power cable going from the GPC to the starter is brand new.

[Gadgetmason]

I'll look up the code number for the glow plug controller, if yours is the same as a 1996, I was able to pick one up at AutoZone for only 46 bucks. There was a standard GM part. And if you're a veteran, you get an additional 10% off. I brought the original part into the store, and they were able to pull the part number directly from the part and look it up. Luckily the store I was at had one in stock.

[ericward]

Oh ya, and no codes.

[Gadgetmason]

Glow plug cont, does not code out. Sometimes, like mentioned, no wait light.

[Gunshow]

Change the glow plug controller Eric, just to see if that's the issue. Part is cheap.

[RIH1]

A small piece of heavy gauge wire can also be used to "jump" the controller. mimic the on/off cycle and you will heat your plugs manually. Then jump in and start up the truck.

I have seen conditions where trucks need a good GPC even in temps above 50 degrees.

[ericward]

It's not glow plug controller related, there is no fuel coming out of the IP and the GPC does not control the PMD or IP.