Misfire @ Idle

[OneJArpus]

Ok 1.5jz swap single turbo new coils...


I had NGK I12 iridium plugs in there, no gap done to them, they would idle good and some times mis slightly. But in the upper RPMS 4/5K they would misfire bad (in boost)

I figure what the hell let me change out the plugs, i tried out NGK BKR6ES-11, gapped at .028 each, now the fucker misfires at idle all the time and even worse then the I12's... but in boost, til redline it does NOT sputter what so ever. Did i gap them too low? high? just right?

Input please. thanks

 

[destrux]

Bigger gap makes the idle smooth, smaller gap prevents blowout under boost. You have to find the biggest gap you can run without missing under boost. My idle was rough with a gap under .025", over that it was only a slight miss, till .030" when it started to idle smooth. Seems to match what I've heard from other people here too. I run BKR6ES also.

 

[te72]

I forget which exact plug I've run in my car, but it doesn't idle perfect (not horrible either), but it doesn't miss under boost either. I'm gapped around .028 here. Copper > Iridium on our cars.

 

[Suprasonic19]

I just switched to ngk v-powers from the super platinums to see if running copper would smooth out my misfire and it made it worse. Before itd miss and stumble about every 3 to 5 seconds, Now it misses almost constantly at idle and even stalls now. I had a .028 gap in the plati and I gapped the coppers to .031 Ill try regapping to .028 and the coppers and see what I find.

 

[suprahero]

These are what I run http://www.summitracing.com/parts/NGK-4644/

.028 should not make it idle that bad and it should help with the miss under wot. I don't think the 6 heat range on the ones you installed are made for our car. Try the ngk4644's and see if it helps you.

 

[IBoughtASupra]

Arpus - Are your coils new from the dealer or you mean newer used set?

I have new coils from Toyota and all the hi-power guys run just a DLI and they have no miss whatsoever.

If you are on a standalone, get a set of 1ZZ coils and run those. You can run a .040 gap in boost with those suckers and they don't miss and that's without a DLI. Imagine what it would do with a DLI.

 

[Devin LeBlanc]

To me sounds like cracked coils arcing to the head. However they would usually do it under load.

I run BKR7E's gapped at .20 running 20 PSI No idle or spark blow out issues

 

[te72]

.028 should not make it idle that bad and it should help with the miss under wot. I don't think the 6 heat range on the ones you installed are made for our car. Try the ngk4644's and see if it helps you.

Now that Devin posted the BKR7E thing, I think I'm running the BKR6E, and have been since the car had the issue with the gap being incorrect... runs just fine for the most part with the 6 heat range plug, but I've never run the 7 range to compare.

 

[suprahero]

I've never ran anything but the BKR7E. Always worked perfectly for me.

 

[Suprasonic19]

Finally got my misfire at idle figured out tonight. The cps was off by 3 teeth. Might be something you wanna check.