Misfire cylinder 7 after it warms up, advice???

[hammdo]

Just wondering if you checked for a weaking valve spring on number 7? There are test tools to verify if a spring is weak or not. If you've check the plug, wire, injector, coil, and verified no shorts in the connection, may be the next step after you've eliminated the obvious.

-Don

[simon.w]

One last thing to check ... take it to someone like kragens, oreilly's, autozone and get them to check the battery. My car was having issues when it warmed up because of low voltage from a dying battery. It would typically happen after I started the car when it was warm ... had difficulty cranking ... would throw a code, (traction control etc warning lights would all be on and either the tach or speedo wouldn't work) and then it wouldn't run right until it had cooled down and I could clear the code with my SCT-X10.

If that doesn't work, time to take it someone who can run it on a dyno, log it thoroughly at all RPMs and also do a leak down test.

[Unreal]

Whats the plug gap at?

[simon.w]

Originally Posted by Unreal

Whats the plug gap at?

The OP changed plugs ... and swapped with other cylinders ... I can't see this being the issue.

It's gotta be these little dudes

[Unreal]

#7 typically runs the leanest and will be first to show issues. New plugs gaped way to large, and old plugs gapped too large could easily do this. Just something to rule out.

[simon.w]

Originally Posted by Unreal

#7 typically runs the leanest and will be first to show issues. New plugs gaped way to large, and old plugs gapped too large could easily do this. Just something to rule out.

Agree ... #7 was set off alarm bell in my head too!

[BlaqWhole]

Originally Posted by Jeffgis12b

The guy I bought it from knows very little about cars or performace mods and never had a problem but he bought it as a conversation piece and investment, he only put a couple hundred miles on it in 2 years and soon relized the $890 bucks a month payment wasnt fun anymore. I talked to the guy that had it built and he had zero issues and was somewhat suprised i was dealing with any issues. I put almost 300 miles before an issue surfaced.

FYI I did hit the rev limiter a couple times by mistake as I was trying to Learn the car.

So basically, he washed his hands clean and is telling you "don't bother me with this crap". Nobody supercharges a Camaro SS and then only drives it 200 miles in 2 years. He messed something up, dealt with it for 2 years, and dumped it on you. So of course he "is surprised" and "had zero issues with it". That 200 miles he put on it was the 200 miles before it had problems.

Now I hate to be all Gloomy Gus, but to me it sounds like you may be having an internal mechanical issue. Especially since the problem is staying in the same place. You might have to pull the head to find out. Sorry but these things happen. Another thing, I would not trust a car that has 16 codes because of the O2 sensors especially when that car has an aftermarket SC on it. I'd say while you're at it to get that problem fixed and tuned properly.

[Jeffgis12b]

Originally Posted by BlaqWhole

So basically, he washed his hands clean and is telling you "don't bother me with this crap". Nobody supercharges a Camaro SS and then only drives it 200 miles in 2 years. He messed something up, dealt with it for 2 years, and dumped it on you. So of course he "is surprised" and "had zero issues with it". That 200 miles he put on it was the 200 miles before it had problems.

Now I hate to be all Gloomy Gus, but to me it sounds like you may be having an internal mechanical issue. Especially since the problem is staying in the same place. You might have to pull the head to find out. Sorry but these things happen. Another thing, I would not trust a car that has 16 codes because of the O2 sensors especially when that car has an aftermarket SC on it. I'd say while you're at it to get that problem fixed and tuned properly.

The feel the guy I bought it from truly didn't know anything and honestly I put almost 300 miles on it before the issue occurred - it's just part of buying performance Inhanced cars, I am not upset about it just trying to figure it out, at this point it's gonna be out of my hands and I am gonna let a shop figure it out. I might do a leak done on it but not sure it even matters at this point as whatever it is its past my knowledge to fix it

[BlaqWhole]

Originally Posted by Jeffgis12b

The feel the guy I bought it from truly didn't know anything and honestly I put almost 300 miles on it before the issue occurred - it's just part of buying performance Inhanced cars, I am not upset about it just trying to figure it out, at this point it's gonna be out of my hands and I am gonna let a shop figure it out. I might do a leak done on it but not sure it even matters at this point as whatever it is its past my knowledge to fix it

Well the good thing is that if it something with the heads then that is a rather inexpensive fix. Hopefully tho it is something minor. I never buy used forced induction cars from independent sellers especially if it is aftermarket. If I do, I get it re-tuned first just to make sure everything is good. Good luck man.

[Jeffgis12b]

Finally got the tools to do a leak down and as many suspected #7 failed with a 45 percent loss and was blowing back threw crankcase(oil cap)

I have question for everyone, I am told alldata shows dropping the motor out the bottom and I was wondering if there is something I am not seeing that keeps me from pulling from the top?

[ChargedCamaro]

Originally Posted by Jeffgis12b

Finally got the tools to do a leak down and as many suspected #7 failed with a 45 percent loss and was blowing back threw crankcase(oil cap)

I have question for everyone, I am told alldata shows dropping the motor out the bottom and I was wondering if there is something I am not seeing that keeps me from pulling from the top?

You can pull it from the top, but pulling it from the bottom by dropping the whole cradle is much easier

[blake-b]

Originally Posted by Jeffgis12b

Finally got the tools to do a leak down and as many suspected #7 failed with a 45 percent loss and was blowing back threw crankcase(oil cap)

I have question for everyone, I am told alldata shows dropping the motor out the bottom and I was wondering if there is something I am not seeing that keeps me from pulling from the top?

If you have a lift, drop the whole cradle. If you don't have a lift, you can pull it out the top. My car is currently on jack stands in my garage and I took the engine out the top.

I pulled the engine and trans together and it was very easy. Easier (in my experience than pulling just the engine) in the long run because I am changing the clutch and I'd much rather do that and put the trans back on with them out of the car instead of laying on my back under it trying to get it in place.

Since you live in Liberty and I live in KC North just outside Liberty, if you want some help - let me know.

I took the front fascia off and lifted the rear higher than the front to allow for the natural tilt of the engine/trans combo. It came out very easy. I just hope it goes back in half as easy.

[2012InfernoSS]

It can be pulled through the top pretty easy, I did mine without air tools and unbolted the ac compressor and left it in the engine bay so I didn't haft to have it re-charged

[simon.w]

Originally Posted by Jeffgis12b

Finally got the tools to do a leak down and as many suspected #7 failed with a 45 percent loss and was blowing back threw crankcase(oil cap)

I have question for everyone, I am told alldata shows dropping the motor out the bottom and I was wondering if there is something I am not seeing that keeps me from pulling from the top?

Sorry to hear that.

Know the feeling all too well!

So ... What's you your shopping list for the rebuild?

This is where the fun starts!

I know you don't have to remove the front clip and radiator to lift the engine ... But given it is only 30 mins work ... I personally would be inclined to do so, to eliminate any risk of damaging either when you remove and refit the motor.