G4+ Fury - 1.5JZ - misfire around 5000RPM @ full load

[Dean]

Hello!

I'm helping a friend out, it's a car I wired a couple of years ago.

1.5JZ, G4+ Fury, R35 coils, E85, 500kw+ at the wheels.

The car was initially tuned with Yaris coils, and it was fine for a while, but the coilpacks started to "die" more often than not, so we changed to R35 coils. It was tuned again and all was good.

It has a new engine now and has developed a misfire around 5000rpm. It'll rev out with partial load. 

Can anyone help with any ECU setting ideas before we look mechanical? ie. dwell settings. It's a bit hard to see what's happening in the logs, but it's often at full throttle between 4-6k rpm.

Log and tune: 2 Items

My own car (which is an identical setup) had a similar issue that was resolved with upgraded valve springs as it seemed like the valves were pushing open.

 

 

[Tim D]

Could you include all knock data and FCut and ICut in the log please?

It looks like the knock threshold is being exceeded in places so I expect that knock control is pulling timing?

[Dean]

8 hours ago, Tim D said:

Could you include all knock data and FCut and ICut in the log please?

It looks like the knock threshold is being exceeded in places so I expect that knock control is pulling timing?

Thanks for spotting the knock levels, they’ve usually been pretty tame, so I’m not sure why they’re so high now. 
 

Next event is this weekend, so I’ll try to get more data. 

[Adamw]

You havent really logged enough relevant channels to cover all the common possibilities, a PC log would be better if you can strap a laptop in somewhere.  

Are you sure it is not traction control?  In some places in the log the slip % looks to be too close to the target for it to have been disabled.

The fuel pressure also becomes quite erratic above about 5000RPM in the 2nd half of the log, possibly a cavitation issue when the fuel is hot or similar. 

[Dean]

1 hour ago, Adamw said:

You havent really logged enough relevant channels to cover all the common possibilities, a PC log would be better if you can strap a laptop in somewhere.  

What more should I log at the moment? PC log won't be possible as the next event is a paid passenger ride weekend.

2 hours ago, Adamw said:

Are you sure it is not traction control?  In some places in the log the slip % looks to be too close to the target for it to have been disabled.

I'll disable traction control completely. It should be off all the time, but I'll double check. I just realised the settings are from my car, which uses a 12 position knob, this car doesn't have one installed.....

2 hours ago, Adamw said:

The fuel pressure also becomes quite erratic above about 5000RPM in the 2nd half of the log, possibly a cavitation issue when the fuel is hot or similar. 

The issue happens straight out of the gate at 30deg fuel temp, but I'll keep an eye on the issue you noticed. Fuel temp looks to reach max 50deg by the end of the day (ethanol sensor temp)

[Adamw]

I just noticed you had traction limit status logged so that looks ok.  I would add dwell, trigger error counter, ign & fuel cut, to the log set.  Increase diff fuel pressure logging rate to say 50Hz to get a better idea how bad that is.  You can probably remove fuel press, aux 6 & aux 8 from the log set to gain a bit more bandwidth.  

[Dean]

Here's a log from the first session today, and the current tune. I asked him to keep the logger on so hopefully you can see where the misfire is. (3m4s, 3m7s, 3m8s are good examples)

2 Items