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Location:
Parramatta
Registered:
July 2002
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backfiring and poping
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Tue, 06 August 2002 02:51
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hey i own an mr2 aw20 turbo...3sgte im having a problem its backfiring and poping at about 5000 rpm some times a little less i have ems and bits and pieces done to it it runs 15 PSI it all started to happed when i blew spark plug tips off then i replaced them gapped them a little more cause of the extra boost and it still backfires etc what the hell is the problem i cant work it out for the life of me when it starts to backfire it wont rev anymore therefore it goes like crap help please...........
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Location:
Sydney
Registered:
May 2002
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Re: backfiring and poping
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Tue, 06 August 2002 03:12
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Its probably pinging its tits off..
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Location:
U.S.A
Registered:
July 2002
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Re: backfiring and poping
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Tue, 06 August 2002 03:29
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 "PROCESS OF ELEMINATION"
1. check all the spark plugs
2. check all the plugs wires
3. check all the injectors
4. check all the hose/pipes for boost leak
5. check fuel presure
6. check injector seliniod (resistor)
7. check distributor cap (if its not distributeless)
8. check B.O.V (make sure it holds pressure)
9. check for loose electrical wires and vacume hoses
10. take of the head and inspect the cylinder that start the problem.
Thats all I can think of for now.
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Location:
Sydney
Registered:
May 2002
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Re: backfiring and poping
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Tue, 06 August 2002 06:33
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Close your plug gap to 0.8mm or slightly less (20 thou) and check timing. It sounds like you may be running a bit rich and your current ignition system cant keep up. What plugs you using? Should be around BP8ES if BP6ES etc the plug could be too hot and causing detonation.
Jamie.
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Toymods Board Member
I supported Toymods
Location:
Turramurra, Sydney.
Registered:
May 2002
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Re: backfiring and poping
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Tue, 06 August 2002 08:11
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Check your turbo/exhaust gaskets, & look real close for cracks maybe.
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Location:
Parramatta
Registered:
July 2002
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Re: backfiring and poping
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Tue, 06 August 2002 09:38
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thanx guys i apprecite it all... i have gapped the plugs0.6 so there fine and its not pinging i have all the ems ignition wiring all done so it can cope and its not the timing out cause i just got the timing belt done its all good there i will go through 666supras check list everything else i have elimated ... thanx guys
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Location:
North Sydney
Registered:
May 2002
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Re: backfiring and poping
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Tue, 06 August 2002 10:55
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Good to see you reduced the plug gap, dont know why you gapped them larger but anyways.
Check your idle map figures compared to full load map figures, your idle figures may be fuelling too much.
is the problem there on acceleration or deceleration, on boost or backing off?
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Re: backfiring and poping
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Tue, 06 August 2002 11:05
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Send the EMS unit back to the Petes, get them to check out sheilding etc.
It wouldn't be the first time, and if it comes back with "nothing wrong, we just cleaned it ", dont despair, they probly did fix it, it will work fine!!
Great Blokes at EMS, pretty good product (for the price) , they just seem to have a problem admitting the ecu's need repair occasionally.
Matt
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Location:
MACKAY
Registered:
May 2002
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Re: backfiring and poping
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Tue, 06 August 2002 11:25
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MR. 2
It sounds like it's running lean at the higher revs and boost , try richening it up a bit , running to lean will cause detonation and burn off the plug tips .
Trevor
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Location:
Parramatta
Registered:
July 2002
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Re: backfiring and poping
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Thu, 08 August 2002 08:27
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hey guys thanx for the replies... i still cant work it out?! supragte its only on near full boost wich is 15 psi and its not lean if anything its rich and when it hits the poping etc it throws out black smoke and a fair wack of it so i have no idea...
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I supported Toymods
Location:
Berowra-Sydney
Registered:
July 2002
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Re: backfiring and poping
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Thu, 08 August 2002 09:12
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i don't know anything about your engine but on mine it has a pipe running from the valve cover to the air intake of the manifold so it gets rid of any harmful gasses produced by the engine or something and at high revs i get a tiny bit of oil come out through this pipe and into my fuel air mixture and even though its a tiny bit of oil it causes a hell of a lot of smoke, perhaps when you hit these high revs and get a bit of oil go through it fauls up the plug to cause it to missfire. either take the plugs out and make sure there is no oil on them or in the thread or find the pipe i'm talking about, disconnect it and stick your finger in it and see if there is any oil that has been running through it.
i fixed the problem by making an oil catch can pipe running in and one out so only the air continues through to the intake and the oil stays in the container.
just another idea for ya.
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Location:
newcastle
Registered:
May 2002
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Re: backfiring and poping
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Thu, 08 August 2002 12:18
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just a thought maybe if your spark plugs have lost there tips the bits that are missing may have gone out the exhaust valves and marked the valve seats so at low revs the miss is hardly noticable but at high revs when the seats are getting slammed shut and open rapidly its very noticable and causing the seats not to seal when they should therefor the compresion stroke is not fully sealed when it should be maybe,a compresion check may help
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