Just got everything back together after HPOP went out due to disintegrated sump screen under oil cooler in an 04 built 8-22-03. Replaced HPOP with Thoroughbreds/dieselsite adrenaline pump/ oil cooler and sump screen (this time SS upgrade of course). Things were looking good, went about 80 mi into town and back no problems other than an exhaust leak that I found was do to me leaving out a spring on turbo to exhaust pipe(?). Replaced spring (with one off the old turbo tube boots left over from upgrade to sinister boots just installed) and had it idling fine for about 5 - 10 minutes while I checked for leaks. Noticed a funny hiss like an air leak that would come and go. I was trying to trace this down when the engine suddenly jumps up in RPMs to just over 1k and runs real rough. It sounds like the throttle is being stepped on an let off constantly with very fast climb and deceleration and a lot of injector rattle. Scan gauge shows high IPR at <> 2600 and icp <> 27 %. I have looked for wire chaff and unplugged the turbo to no effect. The truck will run fine as long as i am over 1k but sounds rough on things when attempting to idle. Needless to say I haven't run it much more than to diagnose. I have checked the seating of the FICM connectors and it seems that all three plugs are seated fine along with the PCMs connectors. Looked online for similar problems but haven't run into anything like it. Surer would appreciate it if someone could point me in the right direction as It just sounds like it is hard on the new injectors (1-2k on them same time as the new OEP head gaskets and New Age SS ARP head studs). The IPR I am sure is suddenly high but why? Is this cause or an effect?
sudden RPM increase rough iddle
- Thread starter Long Gone
- Start date
Zeb
New member
I think you have your ICP and IPR numbers turned around. IPR should be listed as a %, and ICP as psi.
It sounds like you are losing ICP signal and then it switches to the default setting which will make them idle rough because default ICP is higher than necessary for normal idling.
Is there oil in the ICP sensor plug, and on the pigtail? If there is, that is most likely your problem.
Also see if you have a P2285 code which is lose of ICP signal.
If you find any/all of this, replace the ICP sensor with a Motorcraft ICP sensor for an 05+, and at a minimum clean the pigtail (brake cleaner, air, and then a dab of dielectric grease).
It sounds like you are losing ICP signal and then it switches to the default setting which will make them idle rough because default ICP is higher than necessary for normal idling.
Is there oil in the ICP sensor plug, and on the pigtail? If there is, that is most likely your problem.
Also see if you have a P2285 code which is lose of ICP signal.
If you find any/all of this, replace the ICP sensor with a Motorcraft ICP sensor for an 05+, and at a minimum clean the pigtail (brake cleaner, air, and then a dab of dielectric grease).
ghohouston
Active member
Agreed! Could have also gotten trash to an injector during hpop replacement.
Thank you for the input Zeb and gohouston. I have got those numbers backaswards there for sure, sorry about that. I have suspected that it might have something to do with the ICP, but I was not getting my head around it as the lower value at around 27ish would be running the IPR pretty near closed,(as I was thinking that would still be open a bit) and I could see that would lead to the higher pressure but now as you point out and I am finally remember it if you unplug the ICP it defaults to closing alright, and 27 is closed not just kind of close. Thank you I will get right at looking at that connection etc. I am not getting any codes. I wouldn't think it is anything in the injectors as when it first starts up it will run fine for almost 10 seconds. When I changed the HPOP I pulled the HP oil rails and flushed and blew them out real well. Also blew out the HP oil tube supply lines from the pump through the braided hoses into containers so nothing would get back into the head/block. I tried to suck out the injectors with a turkey baster also but don't think it did much. Did find some things that looked like bunkey balls (repolymerized HPOP screen) in the initial draining of the driver side HP oil rail (the first I pulled), but didn't find any thing more in the drain, cleaning and rinse cycles of the other, nor in the lines. My gut feeling has always been that it was something electrical and I think you have confirmed that, and I know where to go now. I would be surprised if there isn't any oil on that plug. Thanks again.
Update: Cleaned connector with solvent and blew out connector. reconnected and started fine. ICP 1500 and Ipr 15 ran smooth and normal for about a minute or so and then the IPR jumped to 29, ICP 2900 and RPMs jumped to 1100 and romping harshly.
Zeb
New member
Did the ICP plug and/or sensor have oil on them?
Zeb
New member
There is very little wiring on the passengers side top of the motor that would affect how it idles.
If there was oil in the ICP plug it is almost assuredly coming from the ICP sensor.
If there was oil in the ICP plug it is almost assuredly coming from the ICP sensor.
I think the oil was on the plug from the work I did. I noticed it as I was putting the harness back on, but didn't think that much about it at the time. I don't think the sensor is leaking, but it is hard to say for sure. It seems to be sending numbers that are close to where I would expect them to be. I am wondering about the IPR, I am thinking that it is not opening as it should. The fact that the IPR went to 29 from 15 when the IPC went to 2900 from 1500 though kind of flies in the face of that so maybe the IPR change did actually cause the increase in pressure. The oil has to not be very warm yet at one minute in. So I guess the ICP being the problem makes more since as there would be a direct correlation there and for it to be the IPR it would have to be suddenly closing for no apparent reason, and if that were the case you would expect the ICP to at least stay open all the way at 15 as it makes no sense for it to go to 29 (which would direct the IPR to close a bit) the opposite direction needed. Ya I wouldn't think that the passenger side injector harness would have any such effect, it's just that I hadn't been doing anything on the driver side that has all the control wiring. Just weird the timing of it, but there is never a good time I guess. At least I wsn't on the road.
ghohouston
Active member
Also, and i doubt it's your issue, but check to make sure all ficm plugs are fully seated, and all injector plugs are too.
Ok, dont know if its been asked, but judging by your build date, you have an early build with the icp on the hpop cover, instead of the valve cover, correct? If so, those icp sensors are junk, replace the sensor and the pigtail. And go from there.
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Got an ICP and connector coming, but I'm not sure that is going to do it. Almost seems like FICM or PCM gone crazy. It started up great today about two seconds cranking and fired up normal 750 Rpm and smooth. Ran great could increase idle gradually and smoothly and hold what ever rpm I wanted for four minutes and then a couple of small surges and into the high idle (1100) and romping returned. I was thinking throttle position sensor? until this as I don't think sensors should change with the warm up but anything being posible if that is the case then which sensor?
Oh hi gohouston and 6.0 tech. Thanks for the input. yes it is the early 6.0 and I have an ICP and connector on the way. Are you saying to go with the 05 ICP then or just a new old style I'm thinking that your saying go with the 05 version. If so I need to order that instead of the old style as I did. In the case of the FICM I have made sure the plugs are in and found the middle one not quite there and seated it, but it didn't change anything. think I will exercise them by pulling them out and reinstalling them a few times to see if that does anything. The way it can start up and run well for 4 minutes should be a clue to what is going on, but is beyond me at this point as I can't get my head around this. I'm thinking about videoing the scan gauge during a cold start so I can replay monitoring the ICP, IPR, ICP voltage and RPM. Is there anything else I should be monitoring, as I could have my tach in view instead of the rpm. Or I could change anything else if there is something else that would clue me into the problem. Don't know how much this will help as my scan gauge 2 is not real time but I remember there is something in the literature about adjusting update time so will review that to see how much I can do with it.
Zeb
New member
MAT is the temp sensor on the intake manifold. Drivers side of the manifold, gray plug. If it’s unplugged it’ll read -40.
Zeb
New member
You can pretty much rest your mind on the fact that it’s HIGHLY unlikely that it is the PCM or TPS. ICP sensor (preferably an 05+ style because they’re more robust), plug in the MAT, and it’ll probably run just fine again.
I'm sure zeb has done it, but I personally have never pit a late icp sensor in the early place, anf I am not sureif it will fit due to the design of the hpop cover. If zeb says it will fit though, I'm sure it will. He seems to not be fully retarded. LOL 
oke:
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oke:Sent from my VS988 using Tapatalk
Zeb
New member
I'm sure zeb has done it, but I personally have never pit a late icp sensor in the early place, anf I am not sureif it will fit due to the design of the hpop cover. If zeb says it will fit though, I'm sure it will. He seems to not be fully retarded. LOL
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Yeah, it fits fine. I’ve done it on a number of 03 early 04’s.
