took off heads, now having a backfiring issue

[480sx]

It first started when i pulled my heads for the third time(couldnt get mls Cometic to seal) and got the car running with the mls gasket. I was tuning idle with megasquirt and the car starts to pop. Sometimes it will hit 3-4 times together.

It doesnt backfire all the time, but its pretty consistant at idle only. Switched to an Enthalpy tune and it does the same thing.

Ontop of that, the number 4 cylinder exhaust port on the head seems to be wet, and is the cylinder that backfires most often. You occasionaly see a backfire out of three, but never out of two or one.

What could be causing this?

This has been going on for a long time.. Now im close to the end of my build and wish i wouldnt have to be sitting at red lights back firing all the time..

[eazye2000]

Timing maybe? I have no clue..

[pflicht]

Something happened like this to me. I took the head of wrong ONE time and slightly warped it. So needless to say i screwed up the head. Make sure you didnt warp your head.

[Zippy69]

The cometic gasket needs a perfect sealing area. I've talked to a lot of folks who say that unless you are running an insane amount of boost, then it might not be worth the cost. Try a fel-pro perma-torque instead, they are a little more forgiving as they don't need a 100% true sealing area. It sounds like you are having some leaks in your head letting coolant in.Good luck.

[480sx]

Well i followed the FSM and used a torque wrench, im not sure how i would have warped it but im thinking of just changing heads in the near future. I have a few spare ka's layen around.

So you think that could be coolant in the 4th exhaust port..? I was thinking it was fuel, i will dye the water and check that. Its actually filled with water thats why i might not smell it.

Im also going to do a compression check, see what that comes out to. I think i got the HG in right though.

[pflicht]

I followed the pattern to remove the head bolts as well but I still managed to warp the thing. I kept having problems with that motor and coolant getting in places it wasnt supposed to. One time after the the gasket failed, I removed the throttle body and coolant had shot all the way through the intake manifold up to the throttle body butterfly. Talk about frustration. Eventually we moved and the friggin thing blew about a week after the move. We arent allowed to do any work on our cars here (Apartment complex) and I didnt have the money to take it to the shop or buy a new motor for that matter, so I sold the car to the salvage yard.

[ghx407]

Check the spark plugs and your distributor's cap and rotor before changing heads; it's easier, cheaper and could very well be the cause of your problem.