KA24DE-T Breaking up under boost?

[Legit]

Ok so i had a small issue a few weeks ago where I was getting weird break up issues under boost. It was usually only under high boost (13-15lbs) and when it would break up my car would go very rich (10.1 on wideband). I changed the plugs, cap and rotor and the issue went away immediately. Infact the car felt better than before the break up issues. Anyway...a few weeks pass after I did the small tune up and went to a drift event where the car ran great until the end and I started getting small break up issues once again. The car still made power but decided to call it a day once the issue came back.

Anyone have any info why it is doing this? I have a feeling it's a fuel issue considering it goes super rich. I decided to change the plugs again (BKR7e) today just because, I checked for leaky injectors...they're all good. Fuel pump works just fine, FPR is reading 40 psi at idle and I'm assuming is good while driving also. I'll leave it at that for now. If anyone can help me out I'd greatly appreciate it. Any other info you guys need just ask and I'll post up what else you might need to know about the car...it's a built KA-t, .60 a/r, walbro 255, 760cc injectors, aeromotive fpr etc..

[Mikester]

^^I say this a lot, but just to be sure:

If you use any kind of octane booster, then that's your problem. It cooks plugs. The shitty thing is that they will look fine (except for orangish brownish hue) when you take them out; but it will cause bucking/stumbling etc issues under boost & hard accel after it runs thru a bit... If so, run the car as close to empty as possible, fill her up with some 93; then change the plugs and NEVER use it again & you'll be golden.

Aside from that, the only two things I know about KA-t's are:

1. SHit

2. Squat

GL ;)

[Legit]

i don't use any kind of octane booster at all :( just 93 octane. It's a very quick intermittent sound when it breaks up too. Not stuttering randomly, but when it hits high boost it basically sounds like a machine gun.

[Mikester]

^^Hmm... Could be compressor surge. I've had that before by turning the boost up higher than the turbine was capable of supporting.

[Legit]

^^Hmm... Could be compressor surge. I've had that before by turning the boost up higher than the turbine was capable of supporting.
doubt it, turbo is more than capable of 15lbs of boost. Plus it's been running fine for 3 weeks, then started doing this again. Most likely fuel issue, but can't pin point the problem :(

[Maeda]

Gap your plugs tighter. You're blowing out your spark.

[Blues13]

+1 on the tighter spark plug gap.

Had the same issue at high boost 18+ PSI on my SR. Gaping them down quite a bit solved the issues. I also upgraded coilpacks and installed an ignition amp which helped. No more breakups.

[Legit]

At what gap? I just found out my cap and rotor basically disintegrated from the inside. Gap it currently at .034...Where should it be then? (i know this has been covered a 100 times, want to just keep it in the thread though)

[Legit]

my friend with a 15psi + on his SR said to go to .028 gap size..is that right? I'm running 15psi on my KA-T set up

[waxball88]

I had a similar issue after my plugs getting excessive oil on them(plug gasket) and finding a spark plug wire cracked. Felt like the car hit a wall, put in new plugs gapped at 32 and its been running nicely.
15psi to4e daily

People bash the KA when really its poor maintenance of an older engine is when you run into issues. Spare parts are a must but at least they are cheap for ka's
Plug wires crack, dizzys need maintenance, intake leaks etc. Im putting together a KA-T performance thread soon

[Legit]

Yeah Rock Auto replaced my cap and rotor for free luckily. Love buying stuff from those guys, they have awesome customer service. Anyway when I get my order in and install everything I'm going to regap to a closer gap .030 I'm thinking. I will update sometime this week.

[feito]

.028 is good

[Maeda]

Try 0.030, then do 0.028 if it's still doing it.

If its still acting like a little shit, look at the rest of your ignition system.

[ThatKidWithTheOnevia]

Also it's better if you run colder plugs

[AJZax]

I will support next heat range plugs and/or running tighter gap

I'm running .029
No brekaing up even at 24 psi.