1JZ Non VVTI Mystery Breakup/popcorn sound

[Zeb]

Hi Everyone,

Hoping to get a little input on a strange issue we are having. Specs are as follows

• 1JZ non vvti
• G4+
• stock ignition
• stock injectors
• single turbo (6266)
• 7psi of boost it runs great and pulls all the way to redline no problems

Once we up the boost and go for another drive it starts breaking up badly right around 5krpm. That is only at WOT.

Partial throttle no boost it will rev no problem.

I've attached a log of the problem as well as the current calibration.

 

Thanks in advance for any insight,

Zeb

bendis17pullpopcorn (1).llg Bendis17 Update Popcorn.llg Bendis 17.pclr

[Adamw]

Can you try dropping the dwell a little more, those ignitors dont like working too hard and cut sparks as some sort of current limitation - usually right around the RPM you are talking.  But I see that more commonly when someone is pushing like 2.4ms dwell, yours isn't too far off what I would normally suggest. Try it down around 1.7ms at 14V.

Otherwise it really just sounds like a classic ignition energy issue.  You could try reducing the plug gap if not already very tight.

In one of your logs the injector duty is already hitting 85% at ~10psi 5200RPM so be aware it hasn't got too much left in it.