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Discussion Starter · #1 ·
I have a challenge for you powerstroke Genius's.
I am hopping to get some help diagnosing my 1997 F350, Powerstroke with manual transmission.
Here is what it is doing:
Rough idle. Rough running up to 2000rpm. loss of power. Bad mpg. Down to 12mpg or less from 16-18. occasional surging while driving under no load.If you try and hold the rpms at 1800 it will stay there for about 5 seconds and then increase to 2200 and steady.
Here is what I have done so far:
Fuel filter is changed every two oil changes.(3-5000 miles)
Pulled all injectors and had them tested and re-sealed. Replaced one injector with re-manufactured. Replaced harnesses under valve cover. Replaced valve cover gaskets. Checked and cleaned all harness connections.(PCM, IDM etc.)
No codes.
I have an AE scan Tool program. Here is what I have tried and or noticed.
Cylinder Contribution. Never lists the same cylinders. Always 3 random. When running this test it always goes through two cycles on all 8 cylinders and then reports. On occasion it will only go through one cycle(of 8) and then show only one cylinder fault. One other note in regards to an above symptom,when holding at 1800 rpm and it spikes to 2200+ the voltage or the pedal position(monitored by scan tool) does not change.
Sorry for the long post just trying to get all the info.
Thanks to anyone who responds.
 

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You might have a IDM going out OR you have an ICP giving a wrong signal. If you unplug it will it go away?
 

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Discussion Starter · #6 ·
Update, I replaced the IDM with one from a solid running truck. No change at all. I still cannot run a Cylinder cont. test without it throwing 3 random cylinders. Not sure what to do next. Any ideas?
Thanks.
 

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Discussion Starter · #7 ·
Here is an example of the last cylinder cont. test I ran.
Test #1 Fault cyl. 1,2,4
Test #2 Fault cyl. 2,3,5
Test #3 Fault cyl. 2,5,6
If I ran three more it would prob. be different again.
 

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Have you tested fuel pump pressure with a gauge?
Are you able to pull up HPOP Injection pressure and IPR duty cycle with your scan tool?

If the fuel supply pressure and high pressure oil systems aren't up to par, the injection event won't occur exactly when the PCM wants it (late firing) and the fuel won't atomize properly to produce a power-building burn, making throttle response slow.
 

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Discussion Starter · #10 ·
I have checked the them with my AE scan tool and they were within spec. I had a Ford tech put their scanner on and it will only partially communicate with the pcm. He could read sensors however couldn't run all of the self tests. He could run cylinder cont. tests and he had the basic issues I did. It kept showing random cylinders in no order. We suspect the pcm is bad. I am ordering one Monday.
Thanks for posting. I'll let you know what happens.
 
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