here's a question

[selphdanny]

every time i start my truck " when the engine is cold" it studders like is missing on just one cylinder but after a bout a minute or so it goes away and runs like a raped ape ive got 187000 on the clock and haven't missed a oil change yet i was wondering if my hpop could be leaking down while it cools over night and if so how do i check it find out if thats the problem or if it an injector or the harness on one side? thanks

 

[BJS]

has this just started? especially in the past week or so as temps have dropped to be a bit cooler.

My first suspect is that you have a bad glow plug or glow plug relay so that one cylinder is not as hot as the others so you are having to rely on the diesel combustion to warm up the cylinder.

the hpop leaking down would cause a hard start where you're having to crank the engine over so that it pumps oil up to the reservoir before it even starts.

 

[Zookie400]

i have seen temperature sensitive bad injectors that have a dead miss when cold and once they warm up they pick up and the engine runs perfect.

you could unplug each injector while its skipping to find the "dead" cylinder. you will need to run the engine with the valve covers off, and when you unplug the bad guy there will be no change. when you unplug a good one it will mess up the "smooth" running. then you can concentrate diagnosis on the problem cylinder.

you could also try a solenoid click test while its cold, if you have the capability to do so. that would be easier than pulling valve covers.

if it was glowplugs, to have a skip it would need to be REALLY cold....what temps are you seeing? also if an injector was firing and the fuel isnt burning you will get heavy white smoke (that smells like raw fuel).

 

[selphdanny]

well it couldn't be the temperature out side cause im in florida and it dont get below 60 at night so im willing to bet ive got a bad injector. ill do some more investigating later i think those are my stock injectors anyway so it could be time

 

[twt]

You could do a contribution test & that will tell you if you have a weak cylinder & a buzz test. Not a lot of $$ for these two tests.

 

[BJS]

I replaced my GPs and GPR when I was in GA and temps were very similar to what we are seeing right now in FL because of a skip at cold start. I can't say for sure if it was the gp's (all but 2 ohmed bad) or the UVC harness with a bad clip on one of the injectors.

GP's are easy to diagnose an confirm or denounce as the problem.

Injectors cheap/easy diagnosis is to start the engine with the valve covers off and then unplug each injector one at a time. If it does not change or doesn't change as much as the other ones then that's your problem.

I will also suggest that you check your chip to ensure that it is firmly seated and see if the problem is there without the chip.

 

[forddeerediesel]

where would you get a contribution test done at? a local ford shop or at a preformance shop?

 

[Zookie400]

anybody that has a top of the line snap-on type (mac, matco.....) scan/diagnostic tool, or a ford dealer.

can the auto enginuity perform a cutout test?

 

[selphdanny]

ok what do you mean by a contribution test? i dont really understand what that is.

 

[BJS]

Contribution test is done by a computer or test stand. It uses the sensors on the engine to determine if one or more cylinders are under performing. You'll need to take it to a shop to have this done or find a friend with a setup that will run codes for you. However the CCT must be run on a warm engine.


Has the problem gotten worse or better with the cool snap this week?
Does the problem persist if the truck is plugged in?