Misfiring Rotrex K20a HELP!

[Tom eg5]

Hey guys,

Just wondering if i can get some help/opinions on what could be the cause of my issue.

Its a Jdm K20a with a Rotrex C38-61 SC on it. Its recently been tuned and was running great for about a week.

Now its developed a bad misfire under WOT.

The Car drives good cruising around at low rpm with under 5% throttle, but as soon as i step on it.. The RPM climbs to about 3k and then starts misfiring/hesitating/sputtering. It is as if boost is just blowing the spark completely out.

So far i have tried:

- New TPS Sensor
- Different coilpacks
- Iridium Spark plugs heat range 7-9s with gapping from 0.032" to 0.020"
- Checked fuel pressure (datalogs show that it isnt leaning out or anything and AFRs stay fine)
- New MAP Sensor
- Air intake not clogged etc (Boost is being registered in datalogs, so there is no leaks)
- No leaks on my IM
- Quick visual check over most my sensor plugs that the pins were all still intact.

I think thats about it..

It started after i took the car for a 1hr drive; so heat may have been a factor. I also filled up my car with fuel. Could possibly be a bad batch? even though it drives fine on minimal throttle and cruising?

If you have an idea's id love to hear them!

Any help will be appreciated


Thanks

Ash.

[na-118]

have you checked fuel pressure under load? or just at idle?

[Tom eg5]

Only just at idle because my gauge is in my bay. But if it was losing fuel pressure under load would it be leaning out? Or is that not the case?

During the datalog's where you can see it misfiring at about 4-4.5k at WOT, AFRs are still staying constant and not jumping all over the place.. This got me thinking it isnt a fuel issue? But i could be wrong..

[mocchi]

probably try upload datalog?

[Tom eg5]

Do you know how to upload datalog files onto here?

[mocchi]

Do you know how to upload datalog files onto here?

just zip it, upload to any uploading site and link it here

[Tom eg5]

It wouldn't let me upload on this forum but the link is in my build thread here:

http://www.k20a.org/forum/showthread...37705&posted=1

[mocchi]

It wouldn't let me upload on this forum but the link is in my build thread here:

http://www.k20a.org/forum/showthread...37705&posted=1

bad fuel could be a possibility i guess, what was it?
bp 98?

try use copper plugs and gap it to what you want?
dont think youre suppose to re-gap iridiums

btw why is it reading constant vss at 80kph lol

[Tom eg5]

Its tuned on Caltex e85.

You can gap the iridiums if your careful. Thats what i had to do when the car ran fine... Then after the longer drive it started playing up again. Ive been reading that coilpacks can break up under load if they are shorting out.. But i have spare ones ive tried and nothing changed.. Would be bad luck if my spare set had a busted one too haha.

[mocchi]

have you tried to reupload calibration to ecu?

[Tom eg5]

Yeah i tried that a couple of times. Same issue

[na-118]

if you have a spare set of copper plugs, i'd probably piss the iridiums off.

also could be a bad case of fuel.

are you doing the data logging while driving as well or just idle?