Stumped!!!

[06f250powerstroke]

I finnaly got my truck on the ford IDS computer, Im having rough idle issues when the motor is hot, What i have found is in a power balance test cylinder #4 seems to be dropping out and missing, but every once in a while all the or most of the injectors would start dropping out and going crazy on the graph. but heres where it get wierd if i put the truck in drive with my foot on the brake it smooths right out, Does any one have any idea on what is going on here its driving me nuts.

 

[NORCAL6.0]

I finnaly got my truck on the ford IDS computer, Im having rough idle issues when the motor is hot, What i have found is in a power balance test cylinder #4 seems to be dropping out and missing, but every once in a while all the or most of the injectors would start dropping out and going crazy on the graph. but heres where it get wierd if i put the truck in drive with my foot on the brake it smooths right out, Does any one have any idea on what is going on here its driving me nuts.

When mine messed up on the graph, it was doing the same thing, but how dose it drive?? Mine would miss around 2200-2500... The fix, had to put a new HPOP in.

 

[06f250powerstroke]

it drives ok, when you say it would miss at 2200 was the driving or in park bringing the revs up?

 

[Dieselcraft]

Fuel psi?

 

[Silverback]

Interesting, you running a stock FICM? And has it done this from day one? Or just recently?

 

[MorganY]

what was the delta in the power balance on cylinder 4?

 

[NORCAL6.0]

it drives ok, when you say it would miss at 2200 was the driving or in park bringing the revs up?

Did it while driving, but it did do it while just revving, just not as bad. Took 3 weeks to figure it out...I can't tell u much more cause I didn't see the pressure readings

 

[06f250powerstroke]

its done it from day one since i put injectors in it, and its a moderate tuned IDP FICM, Im not sure wwhat the delta on the power balance test was. what should i be looking for. fuel pressure was at 65 psi never moves

 

[chappy]

I'm no expert here but if its done it since injectors I would say its something related to it. Not sayin the injectors but maybe the rail leaking somewhere either a squished injector seal or an injector not set all the way in the cup. Seen that happen plenty before. Could be injector 4

 

[06f250powerstroke]

im going to pull #4 once i get it back from the tranny shop. if it were a rail leaking wouldnt the IPR be doing something funny?

 

[NORCAL6.0]

im going to pull #4 once i get it back from the tranny shop. if it were a rail leaking wouldnt the IPR be doing something funny?

Did you ever figure it out???

 

[06f250powerstroke]

i threw a used IPR and ICP in it and it seemed to work much better but still not perfect im thinking a new HPOP in the spring

 

[FallenAuthority]

Did you ever pull # 4 and see if maybe the copper crush washer was burned up and leaking combustion gas back up into the fuel rail?

 

[06f250powerstroke]

not yet in the next few weeks i will be pulling my truck apart to do some upgrades il see if thats the problem but i dont think it is

 

[Extended Power]

I finnaly got my truck on the ford IDS computer, Im having rough idle issues when the motor is hot, What i have found is in a power balance test cylinder #4 seems to be dropping out and missing, but every once in a while all the or most of the injectors would start dropping out and going crazy on the graph. but heres where it get wierd if i put the truck in drive with my foot on the brake it smooths right out, Does any one have any idea on what is going on here its driving me nuts.

Ficm might have low voltage at idle, but when rev'd up, voltage comes up, and everything's happy?:shrug:

 

[Pizza pig]

Im with Ivan on this one, try and swap the ficm for a good one. I've seen bad ficms do some crazy stuff and show good voltage. The change in load on the engine/electrical system when put into gear is enough to make things smooth out and make things go away. Curious, what did you monitor when you had IDS on it?

Id also check the ficm/injector harness for chaffing.

 

[06f250powerstroke]

Ficm is original im going to have it rebuilt this winter, ive got spare harnesses for both maybe il swap them out to while i have it apart

according to my scanguage all three ficm voltages checked out good