[buickman]

Hi Guys.
I'm fighting with a 96 F350 7.3. Originally a no start issue that threw a code of P1283 = IPR circuit. I purchased a new pigtail for the IPR and put 12 volts to the IPR while cranking and the truck started but ran very rough. I then purchased a new aftermarket IPR and installed. Now all codes are gone but something is still wrong. Symptoms: Truck takes a long time to start, maybe 15 seconds after "wait to start" light goes off. When it does start, it idles nicely for about 8 seconds then gets very rough - rpm jumps up and down. "Check engine" light stays on. If I increase rpm just a bit, seems to smooth out, somewhat normal. If I let run for 1-2 minutes, idle seems to settle down a bit. When key is turned off and trunk is started again, the same issues re-occur. I have the pipes from the turbo to the valve covers removed, but the engine sounds loud to me. I also tried disconnecting the ICP while truck was running - no change. Truck only has 120K and well kept. It deserves better.
Can someone please help me?
Thanks,
Glenn

 

[White95f250]

What code pops up now?

The Y-plenum is removed? Put it back on. No need to run motor without it.

 

[buickman]

What code pops up now?

The Y-plenum is removed? Put it back on. No need to run motor without it.

Thank you so much for the reply. Their are no more codes. I have the Y-plenum off in case I have to remove something again.
Do you think having the y-plenum off is now the issue?
Thanks

 

[White95f250]

Are you able to read live data? IPR % and ICP pressure during rough idle will help us.

Are all injectors firing? You can unplug valve cover connections one at a time to see if anything changes.

Automatic transmission?

 

[buickman]

I am not. My scanner is not that sophisticated. Tomorrow I will try your suggestion and unplug the connections one at a time.
Again,
Thanks

 

[greenskeeper]

failed UVCH ? Remove oil cap and take sniff... do you smell burnt wiring ?

 

[buickman]

.I started over again and got the same results but a step further.
Truck takes a long time to start, maybe 15 seconds after "wait to start" light goes off. When it does start, it idles nicely for about 8 seconds then gets very rough - rpm jumps up and down. "Check engine" light stays on. If I increase rpm just a bit, seems to smooth out, somewhat normal. If I let run for 1-2 minutes, idle seems to settle down a bit. When key is turned off and trunk is started again, the same issues re-occur. I let the trunk run for about 8 minutes this time to let it warm up. Idle seemed to settle down a bit so I was able to test as you recommended. I disconnected the 4 clips on the valve covers- one at a time and then engine responded each time by running poorer, indicating that the injectors are working.
Cleared the scanner and started over and got P1211 - ICP Pressure above/below desired.
Regarding UVCH, I did not detect any smell of burnt wiring.
Suggestions?
Thanks so much

 

[White95f250]

There's an issue with the ICP sensor and/or IPR not responding as it should.

@Patrick Feeley may be kind enough to post those function test procedures.

If you've replaced the ICP and IPR then wiring or connection issues need to be ruled out.

 

[Patrick Feeley]

Here's the ICP and IPR Introductions and P1211 PinPoint Tests (starts at X7). Cheers!

 

[buickman]

I'm thinking I have to replace the ICP. I removed it for inspection, seems ok, no oil present. The numbers on the ICP are 181218 and C916067C. Is this the 1994 to early 1996 or the late
1996 and up ICP?. The best price I find for the early 1996 ICP is $155 whereas the late 1996 and up is $35. Can the later ICP be used in place of the earlier one?
Again, I really appreciate your help

 

[White95f250]

Either should be fine. If you have a local International Parts dealer near you then give them a call and tell them it's for your personal vehicle and they should hook you up on price.

 

[Patrick Feeley]

Get an OEM Motorcraft ICP (same for any sensor BTW). Avoid the cheap Chinese junk! Cheers!

 

[buickman]

Maybe too late. I purchased an off brand listed for 97 up as I was told either would be fine. Started over and got the same result.
Are you sure they interchange and do I need the OEM?
Thanks so much