missfire help please
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From: Las vegas
missfire help please
ok I have a 03 7.3 runs like crap. buzz test says cyl 2 and 4 have high to low side open. the only code that's hard is p1316. it also says cyl 1-3-4 fail balance test but not always some times only 2 fail.... I ohm tested injectors all the way to the idm and all are between 3.1 and 4.2 ish. so I guess I can rule out wiring. it smokes pretty bad if I rev it. it was running good till I parked it for 2 days. I did put HSS in oil 2 weeks ago to try clean out little rough acceleration. I did find my ipr nut fell off and spacer ipr was just floating around on the shaft I put that back together it was laying there.
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Joined: Jan 2011
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From: Puget Sound
4.2 is 1/3 more resistance than 3.1 - that's unacceptable in the world of relay coils. This is akin to having 1/3 less compression in one cylinder. UVCH on driver side bad for sure, and it never hurts to address both sides at the same time.
Hotshot
Joined: Jan 2011
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From: Puget Sound
Not always. "Noisy" connectors read as elevated resistance, and they never stay put with vibration. Well... guess what the 7.3L does while running.
Common root causes of noisy connectors is worn parts that work loose, arcing that damages the contacts, and contaminants between the two contact points. Once it starts, either the connection is finally broken permanently, or the arcing pits the contacts until something in the circuit allows the smoke to escape.
Common root causes of noisy connectors is worn parts that work loose, arcing that damages the contacts, and contaminants between the two contact points. Once it starts, either the connection is finally broken permanently, or the arcing pits the contacts until something in the circuit allows the smoke to escape.
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From: Las vegas
also everything I have read says 2.9 to 5ohms is ok. I did change valve cover because I agree 4.6 is to high it is now 2.9 at 42 pin. new updated valve cover gaskets don't have a connection inside only outside. less connection lower ohms good for truck lol
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Hotshot
Joined: Jan 2011
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From: Puget Sound
Ah... you have the Dorman VC gaskets. While I'm not a fan of Dorman or many other non-OEM choices, the Dorman single-piece VC gasket is a solid upgrade. 
Now you have consistent ohms at the 42-pin connector - that eliminates the UVCH and the injector coils. Changing a component to drop the ohms that much is one thing, but changing a connector and it reduced the ohms? You did not waste your time and money - it was at least a part of the problem.
Now you have consistent ohms at the 42-pin connector - that eliminates the UVCH and the injector coils. Changing a component to drop the ohms that much is one thing, but changing a connector and it reduced the ohms? You did not waste your time and money - it was at least a part of the problem.
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From: Las vegas
by eliminating the connection under valve cover that is a part of factory gasket lowers ohms also and a known issue. now that I flipped the gasket to switch injector plugs my 6 injector fails buzz test. lmfao never fails cause more problems. I'm guessing the idm is just on its last leg. it is original and I have 355k on it. I guess it's the last thing it can be. I also have cyl 1 and 3 contribution of this thing picks cyl next to each other to have issues
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DieselDowdy
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Feb 27, 2012 06:22 PM