M150 2JZ-GTE VVti lean condition after shifting

[Ibrahim]

Dear All,
I have a Motec M150 installed on a supra with 2JZ-GTE VVTi, 6 speed manuaI, Precision 6766 , ID1050. I have a problem after I shift and floor it.I have setup the fuel film on 2000 rpm and as per setup instructions I’m almost 100% on target with closed loop off but when shifting in high rpm around 1.4 bar boost and putting the next gear I get a lean condition for around 0.4 to 0.5 seconds when the boost is getting to 1.4bar again. I have altered the fuel film as much as I can but I reached a point that I can’t get any better , I get a lean condition after I shift and I can’t fix it , the strange thing is that if I increase the main table I get a more leaner condition , the leaner condition when I increase the main table is shorter to about 0.2 of a second instead of a 0.5 when I reduce the main table but when I increase the main table I get lean to 18 afr when the target is 12 but when I reduce the fuel film main table it takes 0.5 seconds but the AFR is around 14.5 when the target is also around 12 which I think is better than getting too lean with a higher main table. I will attach for you a log with the low main table numbers . You can easily see when it happens if you add the warning source in the logging graph as after I get the lean condition I get a lambda warning. The warning is delayed around 0.2 of a second as the logging for warning source is 1 hz. I’ll write below my current fuel film settings and will attach the main table but I’m running at 20% of the main table that I’ll attach. At the end of the log I did a couple of throttle sudden increase at 2200 rpm and it shows that the car is good with the current fuel film main table and is on target.
Fuel Film primary scale:20%
Fuel film primary fast part 30%
Fuel film primary offset 30 ul
Fuel film fast increase time constant 0.05 s
Fuel film fast decrease time constant 0.15 s
Fuel film slow increase time constant 0.15 s
Fuel film slow decrease time constant 0.6 s
I’d really appreciate it if someone can have a look on the log and advise what can be done in the fuel film settings to fix this issue.

[Stephen Dean]

I haven't looked at the logging yet, but if you are using Ignition Cut and no Fuel Cut for the shift, is it possible to get a lean reading on the Lambda trace, even though the fuel mixture is rich, this is due to the fuel that is being injected during the shift remaining unburnt and not consuming the excess oxygen in the combustion mix. This excess oxygen is read by the Lambda sensor and shows as being lean. If the engine recovers after the shift and has no stumble/hesitation, I would not be changing the tune.

[Ibrahim]

Dear Stephen,

Thank you for your reply. I'd appreciate it if you can have a look on the log. Regarding ignition cut , I have ignition cut when anti lag system is on, but in this log the anti lag system was off so I don't see a reason that I would have an ignition cut, my car is a manual and I wasn't hitting the rev limiter. I don't think there is an ignition cut when I press the clutch, so I can't see how there would be an ignition cut. I don't have hesitation after shifting but I'm afraid the car would knock from this lean event after the shift and the car is building boost.