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running real rough, missing

3K views 24 replies 3 participants last post by  freeride707 
#1 · (Edited)
its missing from 1000-2000rpms then smooths out, its more noticible with a load the whole truck shakes.its not too hard to start its been in the 30-40s here at night and it only cranks for 3-4 seconds before starting. has a real rough idle. and if i change the chip to certain tunes it lopes a lot more than it used to.

pulled codes and got a P1211 and P1280 i know what they mean i just dont know what to do to fix the problem

I changed the ICP and fuel filters and still nothing.What next? HPOP? Injector Orings? IPR? HELP this is my only vehicle
 
#4 ·
P1211 is ICP above/below desired level. Is that the only DTC you retrieved? Since you've already changed the oil and fuel fiters and replaced the ICP sensor, the only further diagnostic step in the Ford PC/ED for DTC P1211 is to monitor IPR duty cycle (which requires a scan tool that can read live data). If IPR duty cycle increases to 65% under any condition, the next step is to replace the IPR valve according to the PC/ED.
 
#5 · (Edited)
And a p1280. So two similar codes. I am going to drop the tank and make sure there's nothing clogging the screens. Then I will borrow an AE to test IPR. Thats the one you compare to ICP. I was reading about that in another thread. I'm hoping it's something simple like a sensor and not the hpop itself.
 
#7 ·
here's a :bump: And there is no way in he$$ I would drive it. why take the chance:dunno:

Let me know I can drop the AE in the mail in the morning for you......:thumb:
you should just buy it from me........:hehe: OR get me Chris' tailgate....:woot: I can always borrow the AE back.....:rofl:
 
#8 ·
well its my only vehicle... so if need be ill have to borrow a car but if theres no need

yea if you could send me the AE again please. i havent heard back from adrian.
and we'll see how much this is gonna cost me to fix then I can talk about buying
 
#9 ·
Monitor your ICP actual and your ICP desired readings as well as IPR duty cycle. Both desired and actual readings should almost mirror each other under all conditions. What are the readings doing when the symptom occurs?
 
#11 ·
what should he look for M-chan? I will send him my ae tomorrow, I'm curious on whats wrong with his truck.....esp his tq
 
#13 ·
Well, I'm not sure if you can take active command of IPR duty cycle with your scan tool the way you can using Ford's IDS, but I would think you should be able to see an instantaneous response to ICP when doing so. Before doing any of this, I suggest looking at the IPR valve itself. Look at the two wire connector to the IPR valve itself. If the two wires ever short together, the engine WILL shut down for sure 100%. Look for the nut on the back of the valve itself spinning off and making its way into the "valley". I vaguely remember seeing this on a couple 7.3s after I re-read this thread and had a brainfart. Basically, anything visual that you see first, is what you should repair before you do any further testing. In answer to your torque converter question, automatic transmission diagnosis is not my area of expertise, but I also vaguely recall these 4R100 transmissions were notorious having the TC clutch stuck engaged causing the engine to shut down as you stopped, while in DRIVE. But again, it's been AGES and AGES since I've been under the hood of a 7.3L. Nonetheless, I hope it helps.
 
#14 ·
yea i can test the IPR duty cycle, havent had a chance to do so but i did look at the IPR and the solinoid body on it was loose, tightend it up truck ran better then it got loose again :dunno: im going to test it with the AE today probably and then order an IPR if need be. or ill rebuild this one.
 
#15 ·
did I send u the info on how to test it with the AE? & did u get it??? I hope so, I can't find the tracking #:(
 
#16 ·
Ok so i ran it on the AE today, pulled the same codes again. tested the ICP pressure and volts as well as engine RPM and IPR duty cycle.

ICP pressure started at 500psiat idle then jumped to 724 when the volts went to zero and the highest it got was 2461 at 2600rpms

ICP volts read .5v then went to ZERO the whole rest of the time gotta be a wiring issue

IPR duty cycle never went over 42% at 2600rpms and idle was around 13%, when i changed to my tow tune it loped and it was jumping from 14-18%

Now here is my other issue, according to the AE my RPMs are off by 200 compared to my guage panel, what could be causing this? bad CPS ive got the recall on that so i may just take it and have that fixed i just dont want them trying to do any other work on my truck i hate taking to shops(crooks)

just rerplaced the batteries because they were losing power after sitting. turns over faster but still hard starts, usually takes two tries to get it running.
 
#17 ·
ICP pressure started at 500psiat idle then jumped to 724 when the volts went to zero and the highest it got was 2461 at 2600rpms

ICP volts read .5v then went to ZERO the whole rest of the time gotta be a wiring issue
I tend to agree. Have you wiggle tested the wiring between the ICP sensor and the IPR valve while monitoring all the data to see if it reacts to all the wiggling?

IPR duty cycle never went over 42% at 2600rpms and idle was around 13%, when i changed to my tow tune it loped and it was jumping from 14-18%
Is that 13 to 18% at a hot engine idle? If so, those numbers are way high. According to Bruce Amacker (Navistar Instructor), a "healthy" 7.3L IPR duty cycle should be between 9 to 11% at hot engine idle. I guess this takes the mystery out of why those two codes are setting. If your IPR does in fact have a problem with it, the first step is to replace it and retest. High IPR duty cycle numbers like you're seeing usually indicate a high pressure oil system leak (IPR has to be commanded more closed to maintain the PCM commanded ICP pressure) or weak output from your high pressure oil pump. Do you have troubles starting your engine (particularly when the engine is up to operating temperature)?

Now here is my other issue, according to the AE my RPMs are off by 200 compared to my guage panel, what could be causing this? bad CPS ive got the recall on that so i may just take it and have that fixed i just dont want them trying to do any other work on my truck i hate taking to shops(crooks)
I tend to believe your gauge is off, but to verify for sure would require being connected to another scan tool. A bad CMP sensor would cause this engine not to run PERIOD. And for what it's worth, not all technicians are "crooks", while I won't disagree that SOME are.

just rerplaced the batteries because they were losing power after sitting. turns over faster but still hard starts, usually takes two tries to get it running.
WHY is it hard to start? Monitor the above data while you're having a hard time starting it? Is ICP pressure slow in building up? Is IPR duty cycle pegging at 65% when you have a hard time starting?
 
#18 ·
yea i wiggled the wiring didnt change anything. only got the .5v ICP once.
the pressure keeps going to the default 725psi, like the sensor is unplugged or not getting good connection.

the IPR duty cycle was when its cold, havent been driving it as i dont want to cause anymore damage.
havent noticed any oil leakage, there was some around the ipr but was dried up. none in the valley, so no visible oil leakages, unless the the injector O'rings are leaking

starts right up when its hot. when cold not so easy. all the parameters look normal while cranking, the GP relay doesnt always activate the GPs, someone told me the IPR sends the signal to the PCM for them to activate :dunno: but when i jump the solinoid for 30secs it starts right up.

and yea not all techs are crooks, but the diesel techs ive dealt with around here have been, and my honest mechanic i used to use doesnt touch deisels.
 
#19 ·
tried to start it today to get some more data with the AE before i send it back... wouldnt start, hooked the AE up then it started right up :dunno: IPR duty cycle didnt go over 20% while trying to start. once started the ICP volts was reading 1-1.2v and pressure was reading 7-900, and IPR duty was at 17-18% this was while warming up though, as soon as it warmed up the ICP voltage goes to zero and the pressure defaults to 725psi, but IPR duty cycle dropped to 11% at idle,

once the ICP voltage drops to zero the SES light comes on and it begins to idle rough.

It only reads ICP voltage when COLD below 40* once its warm it goes to zero and defaults the pressure reading, this doesnt seem like a wiring issue, but the ICP sensor is brand new, i guess next is to replace the IPR?

any tips on that? i know you pull the solinoid off the IPR then take a 1 1/8"socket iirc and drill out the square part of the socket and weld a plate to it, pull the IPR and let all the HPOP oil run out into the valley? or siphon it out first?
 
#20 ·
just noticed the valve covers are leaking, not sure whether its diesel or oil, but my guess is diesel and its the injector orings, i will pull the valve covers sometime and see whats going on under there.

also should the IPR duty cycle read with just the key on? it was reading 14% and the truck wasnt even running.
 
#21 ·
just noticed the valve covers are leaking, not sure whether its diesel or oil, but my guess is diesel and its the injector orings, i will pull the valve covers sometime and see whats going on under there.
Valve covers are "leaking". Where exactly do you see them leaking? There is a big difference between diesel fuel and engine oil. For what it's worth you can run the engine with the valve covers removed. Have a look at the spill ports on the tops of the injectors as the engine is running.

also should the IPR duty cycle read with just the key on? it was reading 14% and the truck wasnt even running.
Yes, IPR duty cycle at key-on/engine-off should read 14.84%. That is the default command. When the engine is cranking over and the PCM "sees" CMP sensor input (engine RPM signal) is when it commands IPR duty cycle to increase as needed to provide sufficient ICP to enable a FDCS (Fuel Delivery Command Signal). I believe on a 7.3L IPR duty cycle maxes out at 65%, so if you're seeing those kind of duty cycle readings under any kind of operating conditions, that is when you might suspect a high pressure oil system leak and/or weak high pressure oil pump output.

But by what you're describing so far, we seem to have narrowed the cause of your issue down to erratic ICP signals. Have you "wiggle tested" your wiring yet? Again, I'm not very good with 7.3L engines just by virtue of the fact that I see very few of them darkening my doorstep, but what would bother me at this point is your high IPR duty cycle readings, under the operating conditions you describe.
 
#22 ·
ummm, Your a liar Mike................:mad: YOU ARE VERY GOOD with 7.3's You have pulled out of your hat TONS of info u say u don't know for me & others .....so give yourself credit.....:thumb:
 
#23 ·
Yea I wiggle tested it. Pulled all the icp ipr PCM and the other wiring harness connector cleaned em and still has the same symptoms.

The valve covers are showing a bit of leakage towards the back of the engine but that could be because I park on a incline. Never saw the IPR duty get above 50% even.

Once running the truck has an erratic idle. And runs rough up to about 2300 rpms then smooths out. Truck takes a while to build up enough ICP to start it. Starts around 370psi then builds to over 400 after continual cranking.

Thanks for all the input. Every bit helps
 
#25 ·
an update on this issue. ive replaced the IPR, replaced the connector to the PCM even ran new wires for the ICP circuit directly from the sensor to the PCM i no longer have an open circuit but still a p1280 icp low. its been at the dealership for the past week... they dont know what to do because everything has pretty much been done.
 
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