hey guys been lurking here for sometime have read and used allot of advice over the years from this site. I'm having a problem now that is beating me up. It is a number four miss and contribution code with a number six contribution code. I can be sit at a light and hear the engine stumble and smooth back out several times. No smoke what so ever but very little to no power on take off when it is acting up. the parts i have changed so far are as follows new oem injector for number 4 cyl new dummy plug and standpipe while i was in there and new injector harness. Also changed out ICP sensor as i had one on the shelf. The FICM is reading 52 volts BPD FICM . Fuel pressure is 78 psi at 200rpm and 82 at idle. This is after i put blue spring kit in the fuel pressure was low when this problem first started. Oil is 5w 40 t6 rotellea added rev-X with no help for this problem. Truck starts great 2 to 3 second crank time. I have checked ohms on injector and all read 2 ohms is this ok ? I have seen other peoples results and they seem to be roughly half of this result. New upper and lower fuel filter and OEM oil filter and cap.
truck has kill devil oring heads and ARP studs with about 14,000 miles on them. The engine cranks over very even and smooth so i am not suspecting it to be a mechanical issue but i could be wrong. I'm sure i have missed something so fire away with the questions and i will find answers if i can. it is a 2004 f350 4wd drw with a 2006 6.0.
Thanks in advance for you advice and help.

 

You need to check your blue spring, your fuel pressure should be around 65psi. Anything over 75psi can compromise your injector o-rings. There’s no reason to run fuel pressure that high. I have bigger injectors and a regulated return and I set it at 68psi.

 

New blue spring on order but I need to figure out this misfire. The fuel pressure was too low before when the misfire started the new spring raised pressure but didn’t change misfire condition

 

Have you checked compression?

 

Unless I missed something, you have had a contribution/balance code with #4 and #6, and only replaced the injector #4. I'd change #6 also.

 

Short of actually checking compression, if it cranks nice and even and you dont hear a skip/miss, it might be OK. Check it cold and warm, it might be a problem that only makes an uneven crank when warm (a cracked injector tip will do this only warm).
Use the starter wire on the passenger fender to crank, with the key not in the ignition.

 

Injector solenoid should read about 1.2-1.4ohms across pins if I recall...I have 6 new solenoids if you are interested, all are perfect just left over from an attempted injector rebuild.

 

True, one cylinder with low compression should show itself by causing uneven cranking sound.

 

Cranks even hot or cold and the misfire is there cold and hot. It comes and goes with no rhyme or reason . I’m going to use a different meter to check ohms because all mine checked out at 2. I’m thinking not mechanical or it would be there all the time. Can the ficm cause this from the control side without kicking a ficm code? I only changedthe #4 at the time because it was showing a hard fail and contribution after it got put back together #6 shows a random contribution. Thanks for the help folk it is really appreciated more than you know.

i have AE so if any parameters that might lead me in the right direction are in there let me know.

 

I think i'm leaning towards the logic side of the ficm being bad. Going to buy one to put in it unless someone tells me this is a bad idea.

 

Went by BPD today picked up logic side ficm will put in tomorrow see if problem goes away. Talk gentleman there who said had doing the exact same thing. Ended up being logic board. Fingers crossed here

 

So I hate when I read a whole thread and the person with trouble never comes back with the fix for the problem. So here is the fix for this problem. It is either the connection on the bottom of the ficm or the logic board. Either way changed it out and truck is running smooth and strong again. I also want to say thanks for everyone’s suggestions and comments it always helps to know your on the right track or have missed a important step. Thanks again