FIS Posted July 21, 2016 Report Share Posted July 21, 2016 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? Quote Link to comment Share on other sites More sharing options...
josey Posted July 21, 2016 Report Share Posted July 21, 2016 suggestion,connect press sensor as fuel press sensor and log what is happening. and check fuel correction tables. Quote Link to comment Share on other sites More sharing options...
Simon Posted July 22, 2016 Report Share Posted July 22, 2016 Are you running peak and hold injection? Check the injector set up is correct.Make sure MAP sensor reading is still correct. Quote Link to comment Share on other sites More sharing options...
FIS Posted July 22, 2016 Author Report Share Posted July 22, 2016 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 Quote Link to comment Share on other sites More sharing options...
JMP Posted July 22, 2016 Report Share Posted July 22, 2016 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 Quote Link to comment Share on other sites More sharing options...
Steve Posted July 22, 2016 Report Share Posted July 22, 2016 Does it run when it shows lean? Quote Link to comment Share on other sites More sharing options...
FIS Posted July 22, 2016 Author Report Share Posted July 22, 2016 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 everythingStill dont get with lean symptom all the way. The piggyback only alter crank and maf signal and I dont use maf anymore. Quote Link to comment Share on other sites More sharing options...
FIS Posted July 22, 2016 Author Report Share Posted July 22, 2016 Thank you for the advice and suggestion guys.. Quote Link to comment Share on other sites More sharing options...
josey Posted July 22, 2016 Report Share Posted July 22, 2016 so you had piggyback ecu im car and didnt know about it? great you solve the problem Quote Link to comment Share on other sites More sharing options...
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