i'm having some cold start and poor performance until engine is up to operating temp. truck is at ford dealer where my dad is service manager. they have gone threw all the basics, glow plugs &relay tested good , they replaced the v-c gaskets and replaced part of the inj. wiring harness and replaced fuel pump.(pump was leaking badly and part of the harness tested out bad) truck will start when parked inside or plugged in, but runs very rough upon start up, performance is terrible until it is completely up to operating temperature, then it cleans up and runs like new. any suggestions would be appreciated on what to do next. thanks, pete

 

How many miles on it? Injectors ever had any work?

 

they were swapped out and it didn't run any better, but there where other problems also that weren't addressed. previous owner swapped a set of know good injectors and said he used aftermarket o ring kit, truck didn't run any better. fuel pump was bad and part of the injector wiring harness was bad, which has been replaced since then. this thing had compound problems, so i'm trying to eliminate them. since the iwh and fuel pump repair it now at least will start although it's rough it's some improvement.

 

Did they test the glow plug relay? What about ohming out the glow plugs themselves? It would also be interesting to put a scanner or scangauge on it and see if the EOT (engine oil temperature) sensor is reading correctly. The PCM Changes fueling when it reads that the engine is cold, so it would be interesting to see whether it is reading engine temp correctly.

 

all the basics where checked, gp's and relay are all good. it was put on a late model ford diagnostic machine. showing plenty of oil pressure to injectors. buzz tested the injectors today and dad said at least 2 are very weak and 2 more are questionable. i have 8 extra injectors gonna buzz test those and see if the solenoids are good and go from there. may pull the ipr and clean it, and check dc warm and cold, before start pulling injectors. looks like it may be heading towards injectors though.

 

Honestly if the GP and GPR checked out okay and you're having trouble until it warms up, it does sound like time for injectors to me. If they buzzed weak, I think you're best off to change them out. If time is not an issue you could always send the ones you have to Jim at Rosewood diesel and have them gone through before you stick them in there. He can make sure they're good to go and get them flow tested before you put them in. Heck for that matter have him make them stage 1's for a little more money and REALLY wake that thing up! At least that way you would know you're putting in 8 good injectors, and he puts new o-rings on them too.

If mine ever come out of the truck, they will be going to see Jim before they go back in.

 

this sounds like my truck. this truck seems to have plenty of its own issues!

 

Don't waste any time "cleaning " the IPR .. It sounds like worn poppets to me ...