heres the deal. about a week ago it was my turn to have my PMD go bad. It was doing all the typical PMD stuff like hard start, shut of while driving, etc. So i replaced it with a brand new one from stanadyne and went ahead and left the old one to cook and mounted the new one on a heat sink and away from the engine. Everything was fine. Now suddenly the truck doesnt want to start anymore when its hot. cold it cranks a couple more times than it used too but starts right up. when its hot u better not be in a hurry cuz your not gettin anywhere fast. runs fine once it finally starts tho. Im wantin to rule out PMD or IP because the IP was replaced about 50k ago by the PO but he never replaced the PMD:rolleyes:. I was talking to a guy today and he said that hes had trucks start hard because the injectors were going bad and they were bleeding off the pressure and so i have to crank it while to build up fuel pressure again. It makes sense but do you guys think that could be it? BTW im not getting a check engine light.

Pour about a gallon of water on the pump. Let it sit a few minutes and then start it.
If it starts the pump is bad.


Don't do it while it's running or try to start right after the water without waiting.
Could seize the pump.

mine did that same thing after i did head gaskets and had messed with some of the injector hoses, turned out some were leaking and causing air to be in the system

how is fuel pressure?

how is fuel pressure?
I havent checked the pressure in the injector lines yet but i have good pressure from the LP to the IP.

It would be very coinsidental if it was the IP because I just replaced the PMD and everything was fine for about a week, and then all of the sudden it started doing this, unless the problem all along was the IP.

IIRC we don't really check the high pressure lines.

you could take a couple injectors out and have them pop tested to be sure, they'll do a leak down test at the same time. you can even make your own pop tester with an old injector line, a gauge, and an old jack converted to a hydraulic hand pump.

ok getting really aggravated. I had a theory that the LP wasnt working right because it didnt seem to run when it used to (i didnt hear it run for a few seconds after i shut the truck off like it used) so i thought maybe the IP was starving for fuel on start up. so i fixed that (manual LP control) and it hasnt made a diff. I have tried the water trick since i replaced the PMD but didnt help. It is only hard to start when the engine is hot and even then its only about 50% of the time that it doesnt want to start. It runs like a swiss watch after it finally starts. No codes. No unusual noises, smoke, anything. I thought it could be the IP but it doesnt make sense because if a pumps bad a pumps bad and it woulnt run as good as it does. i havent had a chance to get the injectors tested but im wondering if that is even a real possibility that they are the prob. Any theories??? could it be the main computer behind the glove box going bad??? im getting really annoyed because its hard to pin point the problem when it only decides to do it when your out somewhere instead of at home where you can play with it. any input is appriciated.

Try running with the fuel cap loose. The vent in the cap may be partially plugged. Hot start would have vacume in the tank starving it for fuel.

He says its harder to start on the cold start too, I would suspect injectors, like blueburby said take a couple off and have them tested.

water test

it is NOT hard to start cold. it starts fine after it sits over night or even for a few hours after it is driven. It is only hard to start hot as in if i run to the store or something and come back out 20 mins later to leave, even if it sits for an hour it hasnt cooled down enough and it still does it. I havent thought of the fuel cap, its worth a shot.

DieselPro: I have done the water, doesnt help. It used to when the old PMd was bad, id dump a bottle of water on it and off shed go. but doesnt help anymore.

bk96td: I just got home so the truck has been sitting for maybe ten minutes and i went outside and opeded the fuel cap and i could hear air rushing in and i even heard the tank popping as it equalized. Im thinking if thats the problem then it has nothing to do with the temp of the motor it is just that it has to sit a while untill the little bit that it is venting equalizes the pressure. Im going to steal the cap off of my dads truck:D ('98 6.5TD) and then see what happens

well, it did it again even after making sure there was no vacum in the tank.
My dad is currently thinking it could be a sticky shut-off selenoid/valve. Which would make sense if it is sticking closed. we have a spare somewhere in the shop so im goin to find it and throw it on and see what happens. At this point il try anything. Il keep you guys posted.
keep the suggestions coming incase it isnt the problem. Thanks for all the help so far!