[harkes]

Hello friends

I need your help here. My car consistently goes lean after revving it in P/N. Would someone care to check their car to see if this is "just the way a N55 behave"? Happens both in Stg0 and OTS/custom maps.

https://datazap.me/u/harkes/stg0-goi...rk=137-282-452

[n55david]

Originally Posted by harkes

Hello friends

I need your help here. My car consistently goes lean after revving it in P/N. Would someone care to check their car to see if this is "just the way a N55 behave"? Happens both in Stg0 and OTS/custom maps.

https://datazap.me/u/harkes/stg0-goi...rk=137-282-452

normal

[thejeremyman9]

Yes, normal. Just think of it as the engine being under decel (even though you are in neutral) - all modern cars will essentially shut off or dramatically decrease fuel injection during these periods, whether you are in gear engine braking or just in neutral

[harkes]

Originally Posted by thejeremyman9

Yes, normal. Just think of it as the engine being under decel (even though you are in neutral) - all modern cars will essentially shut off or dramatically decrease fuel injection during these periods, whether you are in gear engine braking or just in neutral

Does not happen during de-cel. It happens when the engine resume idle after the rev. For whatever reason STFT goes negative causing this lean condition.

Try open the log I attached then you will understand.

[thejeremyman9]

Originally Posted by harkes

Does not happen during de-cel. It happens when the engine resume idle after the rev. For whatever reason STFT goes negative causing this lean condition.

Try open the log I attached then you will understand.

I did. The negative fuel trims look like they are just bringing the AFRs closer to stoich. I thought by AFR spike you were talking about when it goes over 20 right after the rev; that's what i was decribing.

[n55david]

Originally Posted by harkes

Does not happen during de-cel. It happens when the engine resume idle after the rev. For whatever reason STFT goes negative causing this lean condition.

Try open the log I attached then you will understand.

normal

[harkes]

Originally Posted by Phantom10R

normal

Not convinced as the engine is bugging down when AFR climb to 16. Feels far from normal.

I am very interested in seeing a log with some revs if anyone could provide, thanks.

[thejeremyman9]

Originally Posted by harkes

Not convinced as the engine is bugging down when AFR climb to 16. Feels far from normal.

I am very interested in seeing a log with some revs if anyone could provide, thanks.

Interesting, did you send it to your tuner?

[harkes]

Originally Posted by thejeremyman9

Interesting, did you send it to your tuner?

Happening on stock map also so not tune related. Even running stock intake and MAF is connected. Might try disconnecting MAF...

[rjd_F30]

Originally Posted by harkes

Not convinced as the engine is bugging down when AFR climb to 16. Feels far from normal.

I am very interested in seeing a log with some revs if anyone could provide, thanks.

Can you be more specific on what you mean by "bugging down" when revving in park, or are you talking about on decel too?

I know you've expressed that you feel otherwise but I'll put another vote in for this being normal. Modern cars nearly or do shut down fuel injection on decel to save gas.

[harkes]

Originally Posted by rjd_F30

Can you be more specific on what you mean by "bugging down" when revving in park, or are you talking about on decel too?

I know you've expressed that you feel otherwise but I'll put another vote in for this being normal. Modern cars nearly or do shut down fuel injection on decel to save gas.

See the log then you will understand. This happens 2-3 sec AFTER decel when idle is resumed.

Decel -> Idle is resumed (closed loop) -> STFT goes negative and engine RPM start dropping (down to 550) -> AFR climb to 16 -> STFT goes positive to correct

I know very well that injectors are shut off during decel (unless needed for burbles).

[rjd_F30]

Originally Posted by harkes

See the log then you will understand. This happens 2-3 sec AFTER decel when idle is resumed.

Decel -> Idle is resumed (closed loop) -> STFT goes negative and engine RPM start dropping (down to 550) -> AFR climb to 16 -> STFT goes positive to correct

I know very well that injectors are shut off during decel (unless needed for burbles).

Ah I see, the small peaks after it's back to idle. I'll offer the obligatory "flash back to stock and try to replicate" advice, then ask again what exactly you mean by bugging down? Is the engine shaking/vibrating/getting rough during these spikes in AFR?

EDIT: didn't realize how extensively modified your car was. Maybe don't flash to stock and instead seek advice from your tuner.

[harkes]

Originally Posted by rjd_F30

Ah I see, the small peaks after it's back to idle. I'll offer the obligatory "flash back to stock and try to replicate" advice, then ask again what exactly you mean by bugging down? Is the engine shaking/vibrating/getting rough during these spikes in AFR?

EDIT: didn't realize how extensively modified your car was. Maybe don't flash to stock and instead seek advice from your tuner.

That log is with stock map >stg0<. Running stock intake with KN filter. In all other aspect the car is running great (except the "usual" cold start hiccups with "cold start remove" option).

[MTWO]

Its normal after shifts to have that, I see it on every log but will you ever get your car sorted out already? Its been forever with issues it seems. Time for an upgrade?

[AmuroRay]

Reset throttle and transmission adaptations, and then try again.

[zinner]

Originally Posted by harkes

Hello friends

I need your help here. My car consistently goes lean after revving it in P/N. Would someone care to check their car to see if this is "just the way a N55 behave"? Happens both in Stg0 and OTS/custom maps.

https://datazap.me/u/harkes/stg0-goi...rk=137-282-452

Decel Lean Fuel Cut Off