Hi guys,
we have here a customer car in our workshop.
It is a Nissan 300zx with VG30DETT and a Link G4X PnP. From the beginning was the car running on idle normaly without any problems on Link with the original CAS sensor. The engine is totaly new, new harness and new injectors. We had the issue that the car was misfiring round abbout 4000rpm for a short time and commes back to live a few ms later when we make a pull on the dyno. At 6000rpm we got misfire again. I take a look in the fueltable when i klick on play in the logfile and the curser is flipping to left and right side extreme in the map. We thouht it was the signal from the CAS sensor and we swapped the trigger wheel to a AEM sensor and made the next pull. It was running like before. Sounds like a variable rev limiter on higher rpm. Change the trigger 1 filter from default to 2 gives no result.
We checked the coils and swapped them from an other engine, but we got the same result. We ordered a set of R35 GTR coils and removed the PMU. Still same result, misfire on 4k and above 6k. The dwelltime is set right. We logged te trigger signal and checked it with the trigger scope. Looks totaly fine and no faulty signals no electrical noises. Trigger error counter is all time by zero counts.
I checked the voltage on the coils, the voltage is by 13.5 volt by full throttle and 235kpa pressure (135kpa of boost). Looks fine to me. The ignition timing is set to 10 degreese and lamda is 0.82/0.80. When i lower the boost it is all time the same result.
We buyed a NZ wireing trigger kit and removed the CAS sensor. We had a issue with the settings but it was my fault. Next day was the car rinning again. I checked timings. After a pull i got the same resut like before. I checked the Trigger signal and error counter. Still no error in the counter. The trigger scope shows a fine signal from -28 to +28 Volts.
I logged wheelspeed and rpm signal. The rpm is not matching with the wheel speed. Looks like that the ecu have a problem to calculate the rpm signal right.
After this dilemma i tryed one last thing. I installed the original MAF sensor, a Nissan ECU with Nistune on it and the original Opti 360 CAS sensor. The car is reving smoth upp to 7200rpm without any problem on boost.
BR from sweden
Christian
PC Datalog - 2022-09-12 10;02;45 am.llgx Sequ och direkt injection.pclx
