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Strange miss-fire...


WJM
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Under high boost...it will do it sporatically. Mid range and up...unpredictable...until you get to 5200-5500 then it starts and thats it, no power, missfiring all the way, shift....missfires wierdly...let of for a few seconds....then goes until that RPM range again.

 

Low boost...anything past 5800 and its that same sutuation.

 

NGK racing plugs about 10k miles old....Accell SS Chrom coil about 2 years old...wires about 6 months old.

 

WRX TMIC

Intake/exhaust

16 PSI max boost

stock internals

'bout 26 deg timing advance

oil cooling system

thick rad and racing coolant

and...some little things here and there.

 

Im thinking ignition related....how about ya'll??

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ignition is a good place to start - plugs, wires, cap, rotor. pull plugs and check them. not familiar with turbo's but with your mods do you think you need a non-stock temperature range plug?

 

could your air-fuel ratios lean out too much at that high RPM? kevin had mad problems with his XT6 running really lean in the high RPM range.

 

you might pull your plugs and have a look. if one plug looks different than the rest you can isolate it to a single strung problem (that plug, that wire, that cylinder). if they all appear the same then who knows - cap/rotor, timing or fuel (injector, pump, FPR, filter). doubtful it's fuel, but maybe it's not getting enough at high RPM.

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is your intake air flow totally un-restricted? I had a "similar feeling" problem, but it was my intake. mine was carbed, so I took the intake/filter off, and ran with the top of the carb open. worked perfectly. I just wasn't getting enough air, and it was choking itself... then I found a different intake for high RPM use.

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WJM,

i figure you saw this - but to keep relevant information together someone else posted in another thread:

 

"Misfire at high RPM was due to a badly clogged air filter."

 

Has a new ultra high flow filter.

 

The plugs that are in it are racing plugs....i guess later this week when i get to the car stuff...I will pull the plugs cap rotor and coil and see whats what.

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hey wjm,

 

sounds a bit like my issue we were hashing out a while back...

 

http://www.ultimatesubaru.org/forum/showthread.php?t=19502&highlight=garner

 

I was sure it was fuel cut but now I'm, not so sure. I've really got to swap back to my stock coil and try it out. I just need to dig it out of one of my parts boxes.

 

I think there's a chance you are experiencing a accel coil failure. It could be a simple test if you have a spare coil, swap it in and see if it goes away....

 

also, I'd check the plugs to see if there is any oddness there liek signs of richness or fouling etc...

 

this seems to be a common issue so it would be great to sort it out.

 

garner

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I've had the same prob. and twice it was the accell coil. Now I don't know if there's more too it, like the coils packin it in from something else but i'm on my third, and it will miss, but it's rare now and nothin like before. My feelin's are that accells are cheap and aren't really worth the headaches. When the warranties up and it dies i'm changing the whole ignition setup

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Under high boost...it will do it sporatically. Mid range and up...unpredictable...until you get to 5200-5500 then it starts and thats it, no power, missfiring all the way, shift....missfires wierdly...let of for a few seconds....then goes until that RPM range again.

 

Low boost...anything past 5800 and its that same sutuation.

 

NGK racing plugs about 10k miles old....Accell SS Chrom coil about 2 years old...wires about 6 months old.

 

WRX TMIC

Intake/exhaust

16 PSI max boost

stock internals

'bout 26 deg timing advance

oil cooling system

thick rad and racing coolant

and...some little things here and there.

 

Im thinking ignition related....how about ya'll??

that coil has got to go. that how mine acted when it started to die. POS accel.

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No direct experience, but I have a couple penny jingling in my pocket, so...

 

My first thought was coil, and/or possibly ignitor circuitry. My money would be on coil.

 

Another thought is pressurized-intake hose come adrift... but seems unlikely with you.

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