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2004 Long crank, surging and dipping idle, brief losses of power

614 views 1 reply 2 participants last post by  ShiZor9 
#1 ·
Howdy,

I've got a 2004 F250 with the following upgrades or deviations under the hood:

Bulletproof Diesel Oil Cooler with stock filtration
BPD EGR cooler
ARP head studs with the good aftermarket gaskets (can't remember if it's black diamond or black onyx that's good)
AirAid intake
2003 Turbo
SCT LiveWire tuner with IDP tunes. Currently programmed in extreme street.

Over the last few weeks I've noticed a problem developing. When starting my truck, I rather frequently encounter long crank times. I can go ten seconds cranking the engine with no start sometimes, though usually it starts in under five seconds. If I attempt to start it immediately afterward, it usually fires right up. While running, the idle will dip and surge without any distinguishable cause. It appears to be temperature independent, though it is more pronounced when my oil temps get above 165 degrees Fahrenheit, and the issues are quite prominent when temps are around 190 degrees driving in town. Problems also seem to worsen the longer the truck is left running. This isn't even a consistent problem, as driving home from work I experienced it quite strongly at a number of red lights, and even noticed it a few times while driving, yet driving later this evening went almost perfectly smoothly.

I have a video recording of my tuner while the truck runs as this surging and dipping occurs, and if I can figure out how to upload or link people to that, I will do so. The summary of the data from the tuner is the idle speed can vary by up to 125 RPM in a very short amount of time, and the injector control pressure can vary by up to 100 PSI. The two variances do not really occur at time same time, nor do they both undergo the same change successively. Example: the idle will surge slightly to 670 RPM, shortly later the ICP reading will drop 30 PSI, then the ICP will jump 80 PSI, then the idle will drop to 600 RPM. The idle is also slightly rougher than it ought to be, but that is likely at least partially because I put 15W-40 oil in last oil change by (sort of) accident, while this change has 10W-30. My truck has always been sensitive to changing oil viscosities.

While it may be unrelated, I will also mention that I have a slow, small coolant loss coming from somewhere as of yet unidentified. Maybe half a quart per thousand miles or more, but it's nonetheless disappearing.

I've only been able to briefly search through the forums for similar people's experiences, and so far it seems to me that I'm having a problem with some aspect of the high pressure oil system, particularly the ICP sensor. The extremely erratic nature of this issue makes me think it's a bad sensor and not a mechanical failure. However, most of the posts I've found are people with either hard start/no start situations, OR surging idles. I haven't yet seen any with both. I'll have more time to look into this on Sunday. I'm hoping to get pointed in a fairly specific direction to start troubleshooting, as free time and money are both in short, short supply for me lately. I can't afford much in the way of repairs for another three weeks, and I'm afraid my truck is gonna go down before that. I hugely appreciate any information anyone can provide me.
 
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#2 ·
Your analysis is pointing towards the ICP sensor plus the possibility of stiction.

Check your passenger valve cover, if your truck is s late 04 the ICP will be screwed into it. Unplug the sensor and see if the truck starts quickly. The ICP will default to a set number and the truck should idle relatively smoothly. If this is the case you'd only need a new ICP sensor and the pigtail, due to the sensor going bad, leaking oil and increasing the resistance on its electrical connection.
 
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