V88 suddenly lean

[FIS]

I am tuning V88 on M3 S50B30, I managed to tune fuel table to AFR target up to 100% TPS, but next morning I started to continue it goes crazy lean to 19. The file doesnt change. I check the things outside ECU like fuel pressure, change fuel filter, clean up injectors and check injectors voltages, everything is fine.
My last try was I changed back Vipec to OEM ECU and AFR goes normal.
Is it possible the V88 got broken?

 

[josey]

suggestion,

connect press sensor as fuel press sensor and log what is happening.

 

and check fuel correction tables.

 

 

[Simon]

Are you running peak and hold injection? Check the injector set up is correct.

Make sure MAP sensor reading is still correct.

 

 

[FIS]

I use std injector with 12.3ohm set to saturation. Swapped with known good V88 the problem still there. 

I use fuel trim to balance the AFR between cylinder. 

Set the fuel trim off doesnt help, 

MAP sensor readings was correct

 

[JMP]

If your fuel system tests out fine (injectors flowing as expected, correct fuel pressure), I'd be double checking your tune for any fuel trims that were overlooked.  Also check that the voltage measures the same at the injector plugs and ECU socket.

If the trims are all zero'd, tune the fuel table, log it and then monitor from there

[Steve]

Does it run when it shows lean?

[FIS]

Finally found the problem! It was loose piggyback bypass connector installed before I handle the car.I removed the connector and repair the cables back to standard. Now the car run smooth but I have to recalibrate timing before start to retune everything

Still dont get with lean symptom all the way. The piggyback only alter crank and maf signal and I dont use maf anymore. 

 

[FIS]

Thank you for the advice and suggestion guys..

[josey]

so you had piggyback ecu im car and didnt know about it?

 

great you solve the problem