My 1996 gmc 6.5 will not start. had stalling problems and have replaced pmd atleast twice now. Well thought that i could be possible wire problem so pulled pmd off wires were worn slightly so i shortened my 6' extention to about 8" seeing as i do not need 6' for mounting on the intake like it has been. but after doing this it will now start at all. i started it before with the pmd i have on it now and my old pmd which was supposed to be bad but now will not start at all with either one.

 

first thing i would do is not mount it in the engine bay. you could hae possibly mixed up a wire when you shortened it?

check your wires, check your grounds, does it crank no start or not even crank?

 

thats just where it was mounted and im just trying to make it through till i have money for new stuff. actual plan is to drop a cummins in it later next year. but no all wires are good lift pump is pumping. was running fine lastnight. not getting fuel to injectors now but fuel shut off on injection pump is good to just got done testing that

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also did unplug the extension wire and plug the pmd straight into the old wire and still nothing. only using two supposibly bad pmd's but both of them ran it lastnight

 

if no fuel to injectors sounds like a pmd and you have two bad ones. like i said really check those wires you spliced and be 110% positive you didnt mix one

 

I did and unpluged the extension that i shortened and plugged it straight into the original pmd wire harness under the intake and still no fire. it defintily sound like pmd but dont get why i was getting fire with both of them lastnight then afterward none at all

 

Where is the original PMD harness ground located?
Often with intake mounted heatsinks the ground wire gets moved from on top of the IP (under OS screw where it MUST stay)to the heatsink for the stock harness to reach.

This can cause a lot of problems all on it's own,since you have an extension harness the ground should be fastened to the IP for reliable performance.

 

Yes it is still grounded to the ip and connections are all good even put electric grease in them and made sure that connection was good. too ground off and made sure it had nice connection too

 

PMD's can fail like that,my first failure would stall hot and then no start for 3 days,or it might start right back up and work great for a day or 2.

 

im going to get a lift pump 2day for a 93 hope that works if not then ops

 

Kyle do this 1st to troubleshoot by method vs just changing out parts Lift Pumps & OPS operation and troubleshooting