Engine miss

JLDickmon

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Thanks JL. How would "fuel desired" impact the issue? Fuel desired is also dropping or is slow to go up on acceleration. Is there any way to isolate 1-2 injectors and the IDM? Really trying to get this narrowed down this weekend.

sorry.. been out in the barn all day fixing damage from a "discussion" the Arabs had..

does fuel desired drop at steady speed rpm?
when you snap accelerate, it should go full throttle almost immediately..

anything else, and I'd almost say it's an ECM issue.. but if the MAP sensor is faulty, has a crack in the vacuum/pressure line, etc., I could see that causing issues.
 

sagebel

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Pulled the grey CPS and put the black one back in. Also removed chip. Ran CCT and failed on #3 and #7 three times. Pulled injectors and swapped #3 and #1, #7 and #5, ran CCT and #1 failed. Lots of air still in the HPOS. I'll take it for a good drive tomorrrow.

Fuel desired will fluctuate between .60 and .98 during the miss between 2400 and 2500 rpm. Seems to only happen after reving it or after KOER.
 

JLDickmon

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Pulled the grey CPS and put the black one back in. Also removed chip. Ran CCT and failed on #3 and #7 three times. Pulled injectors and swapped #3 and #1, #7 and #5, ran CCT and #1 failed. Lots of air still in the HPOS. I'll take it for a good drive tomorrrow.

Fuel desired will fluctuate between .60 and .98 during the miss between 2400 and 2500 rpm. Seems to only happen after reving it or after KOER.

OK.. I'm going to say the injector pulse width is fluctuating because the engine won't maintain a steady rpm if two different injectors fail on the #1 hole, then you're looking at a UVCH problem or an IDM..

the thing that gets me is the #7 went away when swapped to #5...

next thing to do would be to swap #1 and #5 and see if it follows again..
 

sagebel

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Ony one injector failed in #1. It came from #3(original failure). Hopefully I can get the air worked out today and go from there.

I also have an unkown variable in the black CPS. If the IH dealer is open today I might go get a new blue/purple CPS from them.
 

JLDickmon

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yeah, I can't see the CPS causing a misfire...
I think I'd change it anyway, before you forget about it and it quits on you in the middle of a left turn through an intersection...

if the misfire followed the injector(s), you found your problem..
 

sagebel

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Put the new dark grey IH CPS in came up with CCT failures on #2 and #8. Went in and swapped them around. Also cleaned the IPR since I had everything opened up. Can't get anything else to fail. I'll get all the air out tomorrow and I'll see what happens.
 

JRJ04

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to test the idm...you need an injector breakout box to do it properly. it allows you to test each injector circiut individually (from the IDM all the way to the injector)...and all the wiring in between.

Correct me if im wrong, but i believe this is the only way to do it right. For what its worth...i chased a check engine light for months..never had an engine issue, but it turned out to be a bad injector solenoid. I would think if youre seeing a miss that it more of a mechanical issue on the injector.
 

JLDickmon

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Put the new dark grey IH CPS in came up with CCT failures on #2 and #8. Went in and swapped them around. Also cleaned the IPR since I had everything opened up. Can't get anything else to fail. I'll get all the air out tomorrow and I'll see what happens.

I'm having a hard time finding the corollary, but what the hell do I know? :dunno
 

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