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2008 3.5L dodge misfire-cannot solve


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Rbdeal
Novice

Dec 13, 2014, 4:20 PM

Post #1 of 12 (2393 views)
2008 3.5L dodge misfire-cannot solve Sign In

Hi everyone,
I have a 2008 dodge magnum SXT (3.5L HO) that has a cylinder 1 misfire I simply cannot solve. Originally when the misfire cropped up I changed the injector and all was good for about 10k miles. Then it came back-cylinder 1 misfire ; open circuit to injector one. At this point I have: changed injector twice, swapped coil packs, checked voltage to injector (good), had successful compression tests on 1, 3, @ 5 cylinder, cleaned egr valve, replaced PCM, replaced rocker arm assembly, sea foamed, took to dealer for diagnostics (told me to fix rocker arm & injector), replaced spark plugs. No change. Someone. Please. Help.
RB


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Dec 13, 2014, 4:24 PM

Post #2 of 12 (2391 views)
Re: 2008 3.5L dodge misfire-cannot solve Sign In

What code number is it setting now?



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Rbdeal
Novice

Dec 13, 2014, 5:08 PM

Post #3 of 12 (2380 views)
Re: 2008 3.5L dodge misfire-cannot solve Sign In

Hey Hammer Time,
Today I replaced the Rocker arm assembly and the injector for the third time. After I got up to temp the P0201 came back. No P0301 at this point.
Thanks!


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Dec 13, 2014, 5:11 PM

Post #4 of 12 (2375 views)
Re: 2008 3.5L dodge misfire-cannot solve Sign In

So, you aren't getting the open injector circuit code any more?



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Rbdeal
Novice

Dec 13, 2014, 5:12 PM

Post #5 of 12 (2372 views)
Re: 2008 3.5L dodge misfire-cannot solve Sign In

Correct.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Dec 13, 2014, 5:15 PM

Post #6 of 12 (2368 views)
Re: 2008 3.5L dodge misfire-cannot solve Sign In

Why would you replace the rocker arm? You said you had perfect compression. It sounds like you are back to square one and you are going to have to somehow determine if it's spark, fuel or compression causing the misfire before you can begin to find the cause.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Rbdeal
Novice

Dec 13, 2014, 5:20 PM

Post #7 of 12 (2366 views)
Re: 2008 3.5L dodge misfire-cannot solve Sign In

Rocker arms commonly fail on this engine. Mine had the symptoms so i was hoping the Lashes had failed causing the valves to incorrectly open, ashing injectors. And a correction: P0201 is the open circuit fault. However; voltage is good to the injector, continuity checks out in the wiring, and the PCM is brand new. Really having a good time with this one...


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Dec 13, 2014, 5:23 PM

Post #8 of 12 (2364 views)
Re: 2008 3.5L dodge misfire-cannot solve Sign In

What are you saying? Are you getting a 301 or a 201?



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Rbdeal
Novice

Dec 13, 2014, 5:26 PM

Post #9 of 12 (2362 views)
Re: 2008 3.5L dodge misfire-cannot solve Sign In


In Reply To
Hey Hammer Time,
Today I replaced the Rocker arm assembly and the injector for the third time. After I got up to temp the P0201 came back.
Thanks!

So yea, the P0201. Open Circuit.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Dec 13, 2014, 5:44 PM

Post #10 of 12 (2359 views)
Re: 2008 3.5L dodge misfire-cannot solve Sign In

That changes everything. If you have changed the injector and the PCM, that only leaves the wiring in between or the connectors. It's not unusual for the pins to have a poor contact or a bad connection where the wire attaches to the metal terminal. You might want to experiment using an overlay wire attched at both ends by backprobing the connector.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Rbdeal
Novice

Dec 14, 2014, 12:15 AM

Post #11 of 12 (2350 views)
Re: 2008 3.5L dodge misfire-cannot solve Sign In

I was wondering about that today. I'll give that a shot. Because yea, where else could it be? Thanks HT.


Rbdeal
Novice

Dec 15, 2014, 9:04 AM

Post #12 of 12 (2321 views)
Re: 2008 3.5L dodge misfire-cannot solve Sign In

I also wanted to point out that when the engine is cold it runs perfectly. Once it's up to temp the problem occurs, and on subsequent starts with a warm engine.

I did take some contact cleaner to the terminal and it seemed to help, but not solve the issue. Still need to Back probe and experiment with an overlay wire. Again, appreciate the help.
RB.






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