I have a 2002 f350 duelly with a 7.3 powerstroke. It has a miss in it like one cylinder isn't firing. it only does it when I first start it up. After I drive it for a few miles it clears up. You can tell a cylinder is loading up.when I step down on throttle lots of black smoke comes out. One injector gets noisy until it clears out fuel, then injector gets quiet and miss goes away. Some days it will run fine all day. If you leave it idle sometimes it will load up, but clears up while driving.
I changed all the injectors, wiring harness on both banks, IDM, fuel pressure regulator, and rebuilt the so called fuel regulator that goes in the top of the filter housing, where the fuel line is attached and all the glow plugs.
I did a fuel pressure test and I had 68 lbs. I think it's only suppose to have 55 lbs. Not really sure.
I'm begining to think maybe it's the main computer. Getting tired of buying parts that don't make a difference.
Anybody got any ideas?

 

your fuel pressure is spot on. Have you tried synthetic oil? Whats the temperature where you live, in the morning.

 

Does it do any better if it is plugged in for a few hours before starting?

 

I use Amzoil synthetic oil. Weather temp doesn't make a difference. Cold or hot still misses.

 

I tried plugging it in. Didn't make any difference

 

Yeah, you should have come here a long time ago...I know smart#ss ! Anyway, does the truck blow black smoke when the miss starts or does it just not have the power it has when the miss goes away. This sounds like an intermittent electrical problem that is coming/going with the heating up of the wires under the valve covers. Have you tried a cylinder contribution test and a buzz test of the injectors to try to narrow the problem down to an injector? Where you located Gene...maybe someone here that has an AE tester can give you a hand.

 

Are you getting a service engine soon light? I know you said you put in new injectors, but almost sounds like worn injectors, if you took off the valve covers and watched oil discharge cold start you could see a difference possibly. Where did you get the injectors?

 

I had this problem before I changed everything. I had a friend do the buzz test and the cylinder contribution test. Everything checked out. No check engine light comes on. Like I said after you drive a few miles it clears up and runs like a top. When I changed the fuel pressure regulator, the one that is located on the bottom of the high volume pump, (it has a wire gong to it) it did make a difference as far as clearing up sooner.

 

I bought the injectors from thoroughbred diesel. I think one of the injectors is getting too much fuel. What determines how much fuel goes to each injector?

 

I'm not familiar with thoroughbred, do they have a warranty?

 

I'm no help from here, but this comment, i cant visualize.

 

I think he is talking about the IPR.

At this point a compression test might be a good idea...
I think it makes sense to go ahead and see if you can find out which injector is not working when you first start up. A buzz test on cold engine might give a clue, then pull the valve covers and start the engine when cold and see which one is not discharging oil. If they all have oil discharging then check for blowby by removing the oil fill cap.

Good luck. I hope you find the issue soon.

 

Based on what you have said, it sounds like injector issues, my first injector issue with one of these trucks I described it as going along and it was like someone flipped a switch, then all was well, and it would run like a scalded dog.

Looks like thoroughbred has 1 yr warranty, if that is your issue, maybe you can have them tested? Did you buy reman or new Alliants?

 

There is no blowby. we only did the buzz test when engine was hot. We'll try it when engine is cold. Had several mechanics look at it and nobody can figure it out. One mechanic said it could be the map sensor.

 

MAP is a possibility, but I would want live data diagnostics before I just threw more parts at it, Buzz test cold might help, when mine was acting up it was really weak cold vs normal when warm.