Stumped on my misfire issues..
May 5, 2010, 06:02 PM
#1
Stumped on my misfire issues..
Id like to quickly note that ive done all the searching humanly possible..and that YES , we've already done the po300 fix, and the code does not come up anymore We have also replaced all the main things that usually come up, ie : spark plugs, coils, tunes, bov, po300 code, boost leak tests,all good or replaced new, etc etc
The problem happens when i go into full boost at WOT. The car misfires hard and continues randomly misfiring throughout the powerband.\
We've tried replaced the spark plugs ( bpr8es, and bpr7es , at every gap from .26 to .19 even) , Replacing the all the coils with new ones, adjusting the tune, etc etc
My mods are:
Forced Performance Fully Ported Green Turbo
AMS Front Mount Intercooler
Full Race Prostock Exhaust Manifold
HKS Hi-Power Exhaust
Brian Crower 272/272 Cams
Injen Hardpiping Kit
Injen Intake
Hallman Manual Boost Controller
Tanabe Downpipe and Test Pipe
stock ecu custom Tuned (the tune is fine)
Exedy Twin Carbon/Carbon Clutch
Fidanza Lightened Flywheel
Misihimoto Evo 7 Race Radiator
Optima Red-Top Battery
Running on e-85 and pte 1000cc injectors. We were having the same problems on pump AND race fuel btw, and also ran meth with both.
Ive researched about possible ground issues, but am not to sure about that. The misfires are even happening at close to stock boost pressures (21psi) although it randomly goes away after the car has been running for a while...(not a warming up the car issue, car is properly let warm up) so it's not like im producing crazy amounts of power or anything. Logs show No knock, and my air fuels are perfect besides when the car misfires and they fluctuate during the misfire.
At first, I was getting all that 5th gear problems and found out about the po300 code and got that part resolved but we are still have misfire issues all around. The only codes that come up now are for the o2 sensors... i usually just clear the code since i run a straight pipe with no cats but have started thinking of replacing these too.
this is driving me insane. it's a waste of time trying to get the car tuned and dialed in with these misfires...and the problem seems to jump around regardless what tune or how much boost we run...it just revolves around the damn misfiring.
Sorry for the long read but Im begging for any relevant advice on this problem.
Also Ive done two full boost leakdown test and there are no leaks. I have also switched back to a stock evo 9 mr bov.. I had an aps twin vent but we removed it just to make sure that wasnt the problem.
Everything seems to point toward ignition, but there is absolutely no reason why the ignition with new coils and new spark plugs shouldn't be able to handle a measly 21psi on an fp green.
Im almost to the point where i just want to sell the car because there is no reason why it should be doing this! everything seems great except for when the car starts to randomly misfire under wot loads....Logs show everything is great besides the up and downs cause of misfires. Just everytime i try to got WOT it starts misfiring.... thanks for reading. any help would be appreciated.
The problem happens when i go into full boost at WOT. The car misfires hard and continues randomly misfiring throughout the powerband.\
We've tried replaced the spark plugs ( bpr8es, and bpr7es , at every gap from .26 to .19 even) , Replacing the all the coils with new ones, adjusting the tune, etc etc
My mods are:
Forced Performance Fully Ported Green Turbo
AMS Front Mount Intercooler
Full Race Prostock Exhaust Manifold
HKS Hi-Power Exhaust
Brian Crower 272/272 Cams
Injen Hardpiping Kit
Injen Intake
Hallman Manual Boost Controller
Tanabe Downpipe and Test Pipe
stock ecu custom Tuned (the tune is fine)
Exedy Twin Carbon/Carbon Clutch
Fidanza Lightened Flywheel
Misihimoto Evo 7 Race Radiator
Optima Red-Top Battery
Running on e-85 and pte 1000cc injectors. We were having the same problems on pump AND race fuel btw, and also ran meth with both.
Ive researched about possible ground issues, but am not to sure about that. The misfires are even happening at close to stock boost pressures (21psi) although it randomly goes away after the car has been running for a while...(not a warming up the car issue, car is properly let warm up) so it's not like im producing crazy amounts of power or anything. Logs show No knock, and my air fuels are perfect besides when the car misfires and they fluctuate during the misfire.
At first, I was getting all that 5th gear problems and found out about the po300 code and got that part resolved but we are still have misfire issues all around. The only codes that come up now are for the o2 sensors... i usually just clear the code since i run a straight pipe with no cats but have started thinking of replacing these too.
this is driving me insane. it's a waste of time trying to get the car tuned and dialed in with these misfires...and the problem seems to jump around regardless what tune or how much boost we run...it just revolves around the damn misfiring.
Sorry for the long read but Im begging for any relevant advice on this problem.
Also Ive done two full boost leakdown test and there are no leaks. I have also switched back to a stock evo 9 mr bov.. I had an aps twin vent but we removed it just to make sure that wasnt the problem.
Everything seems to point toward ignition, but there is absolutely no reason why the ignition with new coils and new spark plugs shouldn't be able to handle a measly 21psi on an fp green.
Im almost to the point where i just want to sell the car because there is no reason why it should be doing this! everything seems great except for when the car starts to randomly misfire under wot loads....Logs show everything is great besides the up and downs cause of misfires. Just everytime i try to got WOT it starts misfiring.... thanks for reading. any help would be appreciated.
May 5, 2010, 06:25 PM
#2
Evolved Member
fuel pressure? injectors pulsing? tps adjusted properly? any cooling issues? ect? i've seen all these provide some of the issues you are having. a weak f pump may work fine at low loads, but may not pump as hard at wot. the rear o2 sensor helps the computer determine your a/f ratio, so that may also be affecting it. if the rear o2 senses too much fuel out the back,(which is possible, cause you have no cat, ) it may tell the comp. to compensate by going lean and wigging out the comp. it may still be the tune too. you either need to diagnose it or take it to someone who can. throwing parts will just get expensive. good luck.
May 6, 2010, 01:00 PM
#7
fuel pressure? injectors pulsing? tps adjusted properly? any cooling issues? ect? i've seen all these provide some of the issues you are having. a weak f pump may work fine at low loads, but may not pump as hard at wot. the rear o2 sensor helps the computer determine your a/f ratio, so that may also be affecting it. if the rear o2 senses too much fuel out the back,(which is possible, cause you have no cat, ) it may tell the comp. to compensate by going lean and wigging out the comp. it may still be the tune too. you either need to diagnose it or take it to someone who can. throwing parts will just get expensive. good luck.
It's not the tune. My tuner is one of the best on these boards, and he's actually the one stopping me from buying tons of parts i dont need...thanks for the great advice though. it's def. stuff ive been thinking about.
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May 6, 2010, 01:06 PM
#10
. No jerking or loss of power except for the instance of the misfire....it's just a hell of a lot of popping starting with the initial one at first thats big, then the others...
May 6, 2010, 01:09 PM
#11
I've had misfiring issues, never like this so I'm going to throw some ideas out there that may or may not help you and your tuner figure it out.
So it's only at WOT specifically?
Is it in any gear?
Would putting in a boost controller and turning down the boost to say 12 PSI help isolate the issue?
I had the CEL's even with the spacer and ended up having to get one of these which resolved my rear o2 sensor CEL - http://www.o2simulator.com/index.php...5a85894f4a1299
What happens if you go gradual throttle to say 95% and hit the 21 PSI, does it run ok without breaking up?
So it's only at WOT specifically?
Is it in any gear?
Would putting in a boost controller and turning down the boost to say 12 PSI help isolate the issue?
I had the CEL's even with the spacer and ended up having to get one of these which resolved my rear o2 sensor CEL - http://www.o2simulator.com/index.php...5a85894f4a1299
What happens if you go gradual throttle to say 95% and hit the 21 PSI, does it run ok without breaking up?
May 6, 2010, 01:17 PM
#12
I've had misfiring issues, never like this so I'm going to throw some ideas out there that may or may not help you and your tuner figure it out.
So it's only at WOT specifically?
Is it in any gear?
Would putting in a boost controller and turning down the boost to say 12 PSI help isolate the issue?
I had the CEL's even with the spacer and ended up having to get one of these which resolved my rear o2 sensor CEL - http://www.o2simulator.com/index.php...5a85894f4a1299
What happens if you go gradual throttle to say 95% and hit the 21 PSI, does it run ok without breaking up?
So it's only at WOT specifically?
Is it in any gear?
Would putting in a boost controller and turning down the boost to say 12 PSI help isolate the issue?
I had the CEL's even with the spacer and ended up having to get one of these which resolved my rear o2 sensor CEL - http://www.o2simulator.com/index.php...5a85894f4a1299
What happens if you go gradual throttle to say 95% and hit the 21 PSI, does it run ok without breaking up?
