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one plug keeps fouling

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Old 12-08-10, 12:12 PM
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one plug keeps fouling

i have a problem, every month or so the top plug on the front rotor keeps fouling.

i have 1600cc secondaries and 850cc primaries. the car idles and drives and boost perfect. but for some reason that one plug always foul out. im thinking the coil is a little week..
Old 12-08-10, 12:52 PM
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Is the plug getting spark? I havent really heard of to many trailing coils failing. I would check spark on that plug, then if its not firing i would suspect the coil harness before a trailing coil. Thats where i would start for what its worth, good luck.
Old 12-08-10, 12:59 PM
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yes the plug is getting spark. once the plug fouls the car bearly idles and dies, but as soon as i change that ONE plug it starts up like a champ and runs perfect for another month or so, i chaged the plug 6 times already and it started perfectly everytime after i chaged the one plug.

could one one of the 850cc injector be dumping a little more fuel at idle the the other one wich might cause the plug to foul after sometime, i dont think its a harness problem because it starts right up after replacing the plug... but icheck it anyways. thanks.

also what should my a/f ratio be at idle
Old 12-08-10, 01:38 PM
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Whats the leading plug under it look like? If the injector was leaking the leading plug would pretty black as well.
Old 12-08-10, 02:16 PM
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my idle a/f is around 13.5-14.8 depending on the air temps
Old 12-08-10, 02:30 PM
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Originally Posted by FD3S2005
my idle a/f is around 13.5-14.8 depending on the air temps
Mines around 13-13.5 on 850s-1600cc injectors.
Old 12-09-10, 09:12 AM
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wow my a/f idle is around 11:2 how do i lean it out? i have the pfc with hand held comander
Old 12-09-10, 11:11 AM
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Put the 550s back in and use Injector Dynamics 2200 for the secondaries. You will be very happy.

Barry
Old 12-09-10, 11:27 AM
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[QUOTE=revhardallday;10356913]plug on the front rotor keeps fouling.

QUOTE]

Put it in the penalty box.
Old 12-09-10, 11:28 AM
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i would check the coil and the wire.
Old 12-10-10, 09:56 AM
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okay i replaced the wires on the car since the old ones looked old and i dont know how long they been on there.

also the plug that keeps fouling is the lower sparkplug on the front rotor not the top one sorry for the mix up
Old 12-10-10, 12:10 PM
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after replacing the wire does it continue to foul? I would also stick the 550s back in and use the ID2000s as secondaries.

if it still fouls replace the coil.
Old 12-11-10, 07:40 AM
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i replaced the wires yesterday i'll let you know if the spark plug still fouls
Old 12-18-10, 07:42 AM
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okay so last night i was leting the car warm up to take it for a ride and 6 mins into warming up once again the idle dropped and sounded like i was running on one rotor!

so i took out that one plug on the front rotor i beleive its the leading plug wich was the bottom one, the spark plug was very black in color *rich* i assume. so i took out a brand new plug installed it and boooom the car runs fine again. it will run fine for anothe 3 weeks or so and then foul again beacuse this is my 7th time replacing that damn plug, all the other 3 plugs looks ok not too black in color and they never fouled.
Old 12-21-10, 07:33 AM
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im still at it! i think im gonna replace the coil
Old 08-01-11, 01:52 PM
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Did u find a solution to this issue... I seem to have the exact same problem...
Old 08-01-11, 04:52 PM
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if the wires are good/new then the coil would be the next step.

11.2 is rich for idle though, it should be at least in the 12's
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