I have search for a situation like I'm experiencing but nothing quite fits the bill. 03 f350 6.0 6 speed trucks got 160k on it. I replaced the icp sensor(leaking again) and the pig tail about a month ago. The truck drove fine for about 400 miles afterward then it started missing at highway cruise speed (about 1/4 throttle) and seemed like it was wanting to die unless I stabbed the pedal down then it would take off. Happened for about 2 miles then cleared up. I have had it happen at random times since then with no rhyme or reason. Decided maybe Icp I replaced was goofy so I bought another and the same thing is going on. Now it seem to happen more often just after the truck is warmed up and like 5 or so miles down the road. So I decide its finally time to get an AE scanner and see whats going down here. Problem with truck doesn't throw any codes, Icp at idle 600-640psi. Wot 4100 or so, deltas between actual pressure and desired are really close, IPR hovers around 20-25% at idle 84.7 wot, but when I was driving and the bucking surging dieing problem happened the icp pressure showed upwards 3600psi constant at a cruising speed(1/4 throttle, icp should be 1200psi) and of course ipr duty cycle fell on its face. Once problem cleared out readings went back to normal. At first I thought I was having a hpop leak or hpop pump problem but now I'm leaning towards either a wiring problem or pcm issue. Any thoughts and I did try another new icp, no difference.

 

Welcome to FTE.

Post this in the 6.0 section to receive more help.

Are you getting smoke when this happens?

 

Lets see if the Mod will move this for you.

Here is a link to 6.0L Power Stroke Diesel - Ford Truck Enthusiasts Forums

Welcome to FTE.

Sean

 

Welcome to FTE.

As Justin and Sean said, your best help will come from the 6.0L Powerstroke Diesel forum so I've moved your thread down here to it.

 

I assume you are tuned. If so, does it do it w/ the stock tune?

 

Double check the ICP sensor pigtail installation. To show a higher psi the signal wire would have to have a higher voltage one it. Make sure all 3 wires are insulated from each other well. If it looks ok I would pull the IPR and inspect. With the IPR dropping to near nothing with the abnormally high ICP tells me that the PCM thinks the ICP is too high and is trying to lower it. You should have a ICP over/under code in there. Watch ICP desired and ICP actual while it is acting up and see what it says.

 

excuse my language because i was absolutely pissed...but was it doing this?

 

Thanks for the move first off, No smoke involved during "its problem" that I have an noticed. Yes it does have sct tune on it, but with that said it acts the same if returned to stock or under tune. The only difference running wise is that under tune I can keep the truck from shutting off by mashing the pedal and demanding a pressure greater than when icp show the bad pressure reading, it wont do this this in stock calibration, it will just fall on it face and die.

 

Acf6, no mine goes into this absolute dead spot unless I floor it and it clears until I back off the throttle and its starts again. Only will do it once per start cycle usually just pull over, shut the truck off wait about 15 sec or so. during which time the icp will continue to show the bad value (3600psi) then all of a sudden it goes to zip start the truck and runs fine. Did it to me last night and drove 400 trouble free miles afterward.

 

78 the icp wiring is my first stop this morning and double check everything. during the problem event the pressure desired never goes wacko matching the actual. showing an over code icp KOEO. Oh and thanks for the welcoming and the responses. Just got a feeling I'm missing something easy here, Occums razor type deal. Just for a side note a really like the ae. Feel like I have been running blind for far to long, now its just info overload.

 

So the icp desired is 3500 when the actual icp is 3500 while it is running like crap?
What is the ipr and rpm when this is happening?
Sent from my leash using IB AutoGroup

 

No icp actual will show 3600 when desired showing 1300psi. When this happens the ipr shut down to 14% which is what I would expect to do considering the reading coming from the icp. When the surge-dieing happens usually at a cruise but will continue at any rpm till shut the truck off. Now this is the part that loses me, after I shut the truck off and turn the key on the icp actual is still showing that absurd reading for about ten seconds or so then clears out to a normal reading for KOEO. Start up the truck afterward and it drives normal. The hpop actual and desired run together like clock work afterwards and the ipr shows at idle about 22% and 62-79% at wot. Ficm was rebuilt by Ed about 3 months prior to the issue also and still holds 47.5- 48 volts constantly.

 

Pull the ipr and inspect for blockage. You are having the opposite problem most people have with ipr failure, but a blocked ipr would be the only thing that can cause a high icp.

Sent from my leash using IB AutoGroup

 

replaced ipr and icp pigtail last night. (Its amazing just how many parts I have on the shelf for this rig, sometimes baffling). Double check the harness at the ficm to make sure of no chaffing, hook up everything else and pour the coolant back in. Plug the ole AE in and turn KOEO for the glow plug cycle and the icp actual is showing 3600 psi for about 10 seconds or so before I have even started the truck. After the ten seconds the actual icp psi drops to normal for KOEO and viola the truck will start. I'm fully convinced this is a definite electrical problem, almost thinking the pcm is shot. my next move is perform ohm test on the wiring between icp-ipr going to the pcm. Any thoughts on this. Never heard of a pcm going out but the way my luck with this truck is it wouldn't shock me. Oh and the ipr I pulled out was clean as a whistle couldn't even find one little tiny piece of crud in it anywhere (kinda made me happy, go to great lengths to keep the oils system clean) also when I turned the key on the 2289 code popped up immediately (icp to high KOEO)

 

You should isolate and load test the harness as well as ohming it out. If anything it would indicate high resistance some were.