My pathfinder 2001 can start but there is stall issue

[MarkX1912]

For my pathfinder 2001, the IACv was shortened, and the MOSFET of ECM was burnt. I replaced the IACv and the MOSFET, now it can start, but the RPM will drop down to zero and died soon.

I tried to follow the learning procedure, doesn't take effect.

If disconnect the MAF sensor cable, the engine can start up and be in idle well. The stalling issue will be gone. I also checked the MAF voltage, the 5volt and 12Volt both are good. The signal line will change from 0.xx Volt to 3.x Volt when press pedal. It looks good.

Any idea or suggestion? Thanks in advance!

[Rockwood]

Try cleaning the MAF with some MAF cleaner. Also, recheck your work and make sure you replaced all vacuum hoses, and got the air intake tube on tight - could be a vacuum leak.

[MarkX1912]

Thanks much, Rockwood! I have cleaned the MAF. And checked the rework too. BTW, there is stall issue before I IACv and ECM damaged.

[MarkX1912]

The strange thing is the stall issue will be gone if disconnecting MAF cable. If re-connect the MAF cable, the stalling issue come back.

[Rockwood]

Ok, helps to know you had the stall problem before you did the ECM and IACV work.

When you unplug the MAF, the engine goes "open loop". It quits using the MAF and Oxygen sensors, and uses the throttle position sensor, engine rpm, and map sensor to tell how much gas to give the engine.

MAF sensor voltage can't really tell you if the MAF is 100% ok. Mechanics will look at fuel trims as a better check. MAF sensors are kind of known for going bad without setting any engine codes.

If you do not have any engine codes for the oxygen sensors, the MAF sensor probably needs to be replaced.

[MarkX1912]

@Rockwood, Thanks much for your answer! I will try to replace the MAF sensor later.
I checked the code after IACV and ECM changed, there is one P1320

[MarkX1912]

After replace the MAF sensor, the stall issue is gone. Thanks much for help from @Rockwood!

[fleurys]

Thumbs up for rockwood's infos !