SRT6 - Misfire
 

Friends... Bought an SRT6 coupe in June. Starting the day AFTER my car arrived on the transporter, I've been plagued with a misfire on #2. Bunch of good-rep indie shops said

• (1) it's oiling the plug, therefore bad valve or broken ring. Or,
• (2) a digital compression said valves were remaining open, thus the misfire. All these things are possible, and it all looked pretty dire. But as I went from one shop to another, looking for a definitive diagnosis, I began to see a different picture:
• Runs great one day, next day, the miss is back.
• Or, starts with a miss, drive for 5 minutes, shut down, restart, runs great. Or the opposite: runs great, park for awhile, restart with a miss.

I'm not much of a mechanic, but to me that sounds more like an electrical fault with the injector. Assuming that might be true, can I replace just the one injector, or do I need to do them all? And does the process mean dismounting the supercharger (if yes, what maintenance do I need to do while down? New drive belts, change oil in supercharger?), remove the intake manifolds (so a new gasket set for that), pull the fuel rail (even if I replace only one injector)?
I'm trying to establish what I need to do to get this bird (needs wings) back on the road. I'm grateful in advance for any help you can offer.
Thanks... Crow13
https://cimg0.ibsrv.net/gimg/www.cro...a0ea2a4d0b.jpg
Super clean, 66k miles, but with a misfire.


MOD NOTE: Moved to appropriate forum.

Re: SRT6 - Misfire
 

A non-firing injector shouldn't give a bad compression reading.

Re: SRT6 - Misfire
 

That also would not cause oil to be on the plug unless your other descriptions turned out to be in error.

Re: SRT6 - Misfire
 

Understood. The whole "digital compression test" think is a mystery to me. The shop owner gave me the run sheets, and it shows valves for #2 remaining open. But how could that produce the intermittent miss I'm getting? The way it comes and goes is the tough part.

Re: SRT6 - Misfire
 

I didn't see it. The first shop that attempted a diagnosis said they pulled plugs (brand new) for #2 and it was dripping oil. There was no oil on the plugs when I changed them, nor when 2nd shop ran the digital compression test.
Thanks for your help!

Re: SRT6 - Misfire
 

You could try swapping a couple of coil packs and see if the misfire moves? I assume you changed your wires also, you could swap a couple of them also just to eliminate those two components.

Re: SRT6 - Misfire
 

Dripping oil? Did you SEE this with your own eyes?
The more you post about this, the more I think you are wasting your time when listening to that "shop". I doubt there is much wrong with the car.

Re: SRT6 - Misfire
 

I'll "GUESS" if you like. You have 2 intake valves per cylinder. Perhaps one is sticking open at times. It could have a broken valve spring and run on all 6 from time to time and then not. It's been suggested already but I'll say it again. Pulling the valve cover and looking may answer all your questions.

Les

Re: SRT6 - Misfire
 

All coils, ignition wiring and plugs replaced when misfire first detected.

Re: SRT6 - Misfire
 

Dear Pizza guy... that's hopeful. But there's no getting around the intermittent miss. I'm hoping at this point that my tentative diagnosis of electrical fault in the #2 injector is the issue. Isd there a post of you tube vid that shows the process of replacing injectors? What parts involved (besides the injector), ie, which gaskets, et5c. Do I need to change oil in supercharger while removed from the car? Also new serpentine belt?
Thanks... Crow13