1993 Nissan 240sx?@COUPE ...timing issues.

[hapaboi39]

My 240sx keeps like re-timing itsself. I will adjust the timing using a light and making the adjustment via the distributor. It runs okay for about 20 seconds then the timing just goes back to being off-time. Its really strange and Im not sure what to do or why my car keeps re-timing itsself. I had an ASE mechanic look at it and he isnt sure why its doing it either.

I changed the fuel filter, fuel filter regulator, plugs, cap, cleaned the AIV but nothing seems to help it.

Do you guys have any ideas? My roommate thinks its either an 02 sensor or my MAF.

What is your opinion?

Thanks guys!

[180fan]

did you pull the tps and make sure it's fully warm when you adjusted the timing?

[hapaboi39]

no i havent. what is the tps?

[180fan]

throttle position sensor. it's the sensor at the throttle body.

[KADreams]

That is completely normal. You are seeing ecu corrected timing based on the timing map in the ROM. To set your base timing, turn the engine off, unplug the TPS harness connector, start the car, let it reach operating temperature, and set the timing. After it is properly timed, just turn it off, plug the TPS back in, and you are good to go.