92 240sx Code 12 (Air flow meter)??

[92-240sx]

Keep getting a error code for air flow meter change it with another air flow meter from a 12 valve 240sx and mine is a 16 valve does it matter and why do I still keep getting the same error message after clearing the ecu codes. Its running really ruff and smoking bad.

Any information would be great.

Thanks,Jeff

[180fan]

check the plug or wiring. btw the DOHC and SOHC have different MAFS. If you've a SOHC, get the SOHC MAFS and if you've a DOHC, get the DOHC MAFS.

[92-240sx]

Would this cause my car to run bad if the Air flow meter is bad and it would make the car smoke and run really poor.

[180fan]

Yes. Generally you won't be able to rev past 2k if it's totally out. If it's gone bad and not reading properly, it'll make your car run like a person suffering from Montezuma's revenge. It might just have a coating of residue, try cleaning it up with some carb cleaner and run it. If the terminals are grungy, clean it up with electronics cleaner and a small flat screwdriver to scrap the crap off.

[92-240sx]

Ok I finally broke down and bought a AFM for the correct engine I reset the computer and still having the same problems I check the code on the computer and it gives me error 12 and that is the Air Flow Meter. What is the correct way to reset the ECU and why em Im still getting the same error code and the car is still running like crap with the new AFM maybe im not resetting the computer correctly. Or could it be a bad ECU ?

Thanks,Jeff

[slipnfall]

Unlikely a bad ECU. Since you (may) have had a bad MAF, you should clear the learned maps from the ECU. With a bad sensor the computer will try to compensate, and store this as the 'best case' running condition, and will continue to do so, even with a new sensor for some time. Disconnect your battery and let the car sit overnight at least.

Are you pulling the error codes yourself? If so it's very easy to clear them. Anytime after you switch to diagnostics mode I(to get codes), turn the knob on the ECM left, wait, turn right, and the light should stay on. Codes cleared. Check http://www.240sx.org in the FAQ section if this doesn't make sense.

[92-240sx]

Yes we are pulling the codes our self. With the ECU dial turn it clock wise for 2 secs then back to counter clock wise and it blinks one kinda long then 2 fast and thats the only code we get. How would I reset the ECU by disconnecting it for 24 hrs some people total me it can not be rest that way and that it has to be reset by a computer is this correct ?

Thanks for all the info so far.

Jeff

[slipnfall]

Yes most Nissan's that I know of can be cleared this way. It is possible to clear the codes from the CONSULT computer, but this is just a convenience. It shouldn't be so severe as to not allow you to run anyways... it'd only take 15-20mins of driving to 'relearn'.

Check your power and ground connections ::edit:: to the MAFS. Pull back the rubber connector-protector and probe the wires. Black is ground, white is the MAF signal, the other is +12V(with key->RUN). Next start the car, warm it up, and check the signal wire. Should be 1-1.4V IIRC.

[92-240sx]

Ok well here is the latest news I have changed the ECU with a new one and the problem is resolved I guess the computer was bad or the computer did not want to reset from the codes that where in there. Thank you for everyone that has helped me solve and dia my problems.

Thanks,Jeff