6.5TD failing to start

[axemann]

Hi All..

I have a problem.

I have a 96 Hummer, a few weeks ago while idling in my garage it stalled, Like someone reached in and switched off the ignition... It fired right back up, and i replaced the fuel filter soon after, and it didnt happen for a while.

The other day, it started fine, i moved it into my street and then it wouldnt start...the glow plugs would cycle, solonoid would click, cranking speed was there but it wouldnt kick over.

I thought it was the PMD, I have a spare and a relocate kit, i plugged it all in, and it still wouldnt start. so i plugged the old back in... I then jumped 12v to the lift pump which purred fine, and i opened the valve on top of the filter and purged the system...

I then cracked the #1 injector, and wasnt getting any fuel... so i thought it was the fuel shutoff solonoid, i jumped 12v to it, and unpluged it from the harness, but couldnt get it to click. So i unscrewed it and put a spare in, and it started...

I let it run for a while, then shut it down, and it wouldnt restart..., I cranked a few more times and noticed the lift pump didnt run on one occasion...then it ran :/

So i plugged the old FSS into the harness and cranked the motor, and i could see it opening and closing... I then tried the remote mount PMD again, with no luck..

I have two tanks filled with fuel from the Shell Service station i always fill up at, the filter is about 2months old...I havent had this problem before..

I am getting 6ohms at the glow plugs, although i cant reach them all..
and im getting 12.7volts at the batterys, my terminals are good.. although one of my batteries did leak some battery acid the other day when i removed the side terminal to install a UHF radio, i cleaned it all up, and put it back together..this was before the no start problem.

Ive checked all the fuses and theyre good...Then my truck started all of a sudden, so i drove it to the diesel shop where it is at the moment. When driving it i didnt notice any lack of power and didnt notice any smoke...

Im now thinking it could be some sort of electrical problem causing intermitent starting, I havent as yet replaced the lift pump, or the oil pressure switch...When it wouldnt start the engine light was staying on but i couldnt pull any codes from my OBD2 scanner, i dont have a Tech 2.

Can anyone else think of anything? , Im still learning and dont know that much about these motors..

Thanks in Advance

Travis

[More Power]

Sound slike an electrical problem..... Rig a light that glows from the same circuit as the fuel shut-off solenoid. That is tied to a main ignition circuit for the fuel injection system. The light will let you know if shut off problem is related to the 12 v ign source....

Jim

[Robyn]

Would be a good idea to pull any DTC's up and see if there is anything evil lurking.


Good luck

Robyn

[axemann]

Im thinking electrical too, but i piggy backed the multi meter into the harness and when cranking its getting ~12v..

What else is there in the injection pump that can control fuel flow to the injectors ?

I am getting 5psi fuel pressure, between the lift pump and IP, i also jumped 12v to the lift pump with the fuel shut off solonoid removed and it squirted fuel, Mmm its a bit frustrating... Could it be a problem with the PCM not sending a signal to the IP?

Im still trying to get my hands on a Tech 2, we had a Tech 1, I borrowed from someone, but couldnt get it to work although it had the software for the Hummer on it, i think it has to be a Tech 2 to read an OBD2 system?

[ronniejoe]

Yes, you need a TechII or equivalent for OBDII systems.

Is your spare PMD a known good one? Could it be two bad PMD's?

[axemann]

Thanks Ronniejoe, I used a D-Tech PMD as my second, that i remote mounted near the battery bracket...

I have another injector pump on the way, i really wanted to avoid an IP change, but everything is pointing to the pump, and its got to the point where i have to start replacing things as theres no more diagnostics i can do to determine the problem, so i figure while im there ill change the oil pressure switch, and other known to fail parts...

I have arranged for a guy with a Tech 2 to come around and check it all for me.... it was hard to find someone with one over here..

[blackonblack]

Have you had any luck resolving this? I have a '99 6.5TD with very similar simptoms. I have replaced the FSD, ECM, Fuel Filter and had it checked by 3 GM dealers.

Marty