96 6.5TD no start

[jay m]

Hi everyone,
Another newbie on board. Thanks for having me here. I am having some trouble with my 1996 6.5L TD, 155,000 miles. I have owned it for about 9 years and have done the maintenance myself......so far.....w/ out much out of the ordinary. That all changed a couple of weeks ago.
I started having some trouble starting the truck every once in a while, but it eventually started and I didn't think a lot about it. Now it will not start at all. As a note, I replaced the electronic injector module 3 or 4 years ago.
Any way, one day as I was spinning on the motor trying to start it, the glow plug relay and the lift pump stopped running and cycling when I turned the key on to warm up the glow plugs. I replaced the glow plug relay and that did no good. I plugged in my OBDII scan tool to check for codes and there were no codes. However, as long as I have the OBDII plugged in the glow plugs cycle and the lift pump runs when the key is on!!!! when I unplug it, the glow plugs no longer cycle and the lift pump no longer functions??????. I then sent off the powertrain control module and had it tested. There was nothing wrong with it. I put it back on today and the same thing is happening. I wanted some advice before I throw any more unnecessary parts at it. I am leaning on again replacing the electronic injector module. The last one I replaced because the truck would just stop running while going down the road. I remotely installed it on the drivers side firewall. Tomorrow, when the batteries are fully charged, I will try to see if it will run with the OBDII plugged in.
I searched the forum as best as I could for past posts and found none that would apply. I am not familiar with the reference to parts by using their initials and was not sure what y'all were talking about on some of the advice responses.
Strange happenings for sure. Thanks for taking time to read this and I will be looking for your response.

thanks,
jay

[racer55]

Could be a ground problem,clean/repair every and all grounds including both ends of the battery ground cables.

Also the pmd should be remote mounted outside the engine compartment,behind the grill or behind the frt bumper.
Also check each and every fuse you can find for being blown or bad connections.

[jay m]

Thanks, I forgot to mention that I have already checked all the fuses. I did not check any grounds.......yet....... Is there a list of ground points somewhere that I can use to be sure I get them all? How many and location? I'll crawl around tomorrow and check them out.

thanks,
jay

[85-m1028]

Are you getting fuel to the injectors when cranking it over? Have you checked to make sure the glowplugs are all working?

Pull the glow plugs and check em with an OHM meter, and crank it over while they're out to see if fuel blows out the open holes.

[jay m]

I ohmed out all the glow plugs and did have to replace one of them. I took Racer55's advice and checked all the grounds I could find. I found a broken ground wire that should have been connected to the ground point on the top rear of the engine.....racer55 you are the man!...I now have lift pump running and glow plugs cycling again. I have not checked to see if fuel making it past the injectors. I will try that today. What is a PMD and how can I test the thing. Also, is there any way to check the electronic injector module without purchasing a new one? That is what I replaced a few years ago. Are they notorious about failing?

Thanks for the help,
jay

[racer55]

FSD/PMD/electronic injector module are all the same thing.
The only test I am aware of is to replace it and see if your problem goes away.
If they are mounted in the stock location on the drivers side of the injection pump or anywhere under the hood they will fail in a short time,its best to get a relocation kit and mount the PMD outside the engine compartment.
Behind/below the frt bumper or behind the grill is where it will probably have the longest life.

The pmd is a common failure item but the relocation is a means to extend its life.

[jay m]

The truck is in the road again. The problem with the glow plugs and the fuel pump was a broken ground connector on the ground point on the top rear of the engine as recommended by racer55. The no start problem was the PMD (pump mounted driver)/FSD (fuel solenoid driver)......I learned a lot.......To make sure the pmd was the culprit, I was able to plug back in to the old module that is still mounted to the injector pump. It started and ran for about 10 seconds and quit. I purchased a sack full of used ones and will keep them in the truck for spares. After talking with a diesel shop guy that is very familiar with the 6.5L, I decided to leave the module located on the fire wall with the addition of some sort of (homemade of course) heat dissipator. I am eyeing an old lawn mower cylinder head at present, however, I think i'll find some sort of aluminum finned computer housing at the junk yard.

thanks again,
jay

[racer55]

Glad you got it going.
Be sure to have a resistor installed in the replacement pmd,#9 is a common value to gain a bit more fuel capacity or #5,#7 are also good values to use.
I would still urge you to mount the PMD outside the engine compartment,the heat developed under the hood after the engine shuts off and the truck sits is the problem that does the most damage to PMD's and anywhere under the hood will be a shorter lifespan as a result.

[jay m]

Thanks for all your help,
I didn't think about the heat containment after shut down....hhhhhhmmmmm........
Thanks again,
jay