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Un-solved Miss Fire !!!

cameron

By cameron,
in Engines & Forced Induction

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cameron Mentor

cameron

Posted
Posted

Hey,

got a 95 Gtst with standard boost and the usuall front mount, exhaust, pod etc:

any way we have a bad missfire, changed plugs, gaps, coils and it still occurs :cheers:

this is what its like.

turn the car on works fine go for drive and so on. then turn car off and go for lunch and so on then come back and turn it back on it has a weird sort of idle it will gurgle and surg intill you give it a bit of throttle then it'll idle fine ? any way off we go then it will start missing some times at 3k and sometimes at 4krpm and it wont go over it, cause it was that bad. sometimes it'll have a little miss at about 4krpm then it'll pull to redline. other times it'll just work fine and not miss at all ??? it does this in all gears and even in neutral, doesnt matter how much throttle you give it even if you ease it on of put it flat it'll still miss bad.

last month we had it missing really bad (on empty tank fuel) we had the bonnet up looking for leaks and reved it up it was missing then all of a sudden a huge bang(back fire)!!!! their was smoke everywere (white) it sounded like a gun shoot. it did that twice intill we went to the survo and put some petrol in it.... it worked fine after that didnt miss intill later on maby about 1 or 2hr's later it started missing again? Got some new NGK double platnim iridium tips in their and pulled plug number 6 out and it had a crack in it, it was black too.... and their only been their 3 weeks ??? the rest were fine.

what could this be ? were are using an avc-r boost controller and it does it even if its off or on....

thanks in advance.

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https://www.sau.com.au/forums/topic/34256-un-solved-miss-fire/
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cameron Mentor

cameron

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Posted

its not the air flow meter because we have tried another one and it still misses....

today its doing its really bad its missing when its ideling and it was running on 5 cylinders but then their was no miss through the rpm ? but then it started mising through rpm and it ram on 6 cylinders again ? weird.... it stalls a lot too when you push the clutch in 3rd or 4th gear and take your foot off the accelerator, the rpm just goes down to zero intill you take your foot off the clutch then it jump starts it self !!!

hope you guys can come up with some answer cause its gettings quiet frustrating..... :D

cheers,

Cameron

predator Grand Master

predator

Posted
Posted

errr... sounds like its detonating like a m/**er.. um, do you have any compression in cylinder #6 at all? you might want to check that little thing :D

Cracked spark plug? thats not good at all! I wouldn't be driving it like that at all, sounds like serious problems with cylinder 6 cap'in. May already be too late...

cameron Mentor

cameron

Posted
  • Author
Posted

when we took the turbo off all the coolent drained out of the water line and it was fine.. maby a little bit of oil not much though.

we just took the air flow meter wires off and replaced them because they have been dogyed up with wires sticking out everwere.. and it wont start now... but when we unpluged it, it starts ??? but wont rev over a certain point :P

can anyone help ?

Thanks,

Cameron :)

predator Grand Master

predator

Posted
Posted

well sounds like you've screwed up the AFM rewiring then. Check again.

Without an AFM it will start fine, just when you go to open loop mode over about 2500rpm it will refuse to rev past that without a correct AFM signal.

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