I've asked this question before with not much responce, so I thought I would ask again.

I have a 62 Nova with a 355 and a TPI. The manifold, runners, etc are off a 85 but I changed it all over to 1987 sensors, ecm, etc. I used a Painless wireharness. The problem I'm having is when the engine is cold and I take off I get a code set from the mass airflow sensor. now after the engine is warm it will not set this code. anyone else had this problem.

Mitch

 

Which code are you getting? Code 33, 34, or 36.

 

I'm getting a code 33. It was doing this about 6 months ago and then quit, and now its back.. I've replaced the maf sensor 3 times.. new relays, checked the wiring grounds, etc.. It used to set this code at highway speeds only now it does it when I first take off in the morning (cold)..

Mitch

 

The ECM expects to see MAF voltage to be within certain range. This range depends on few other sensor readings. When engine is cold it depends on TPS (throttle position sensor) and IAC settings. IAC provides a path for air to bypass the throttle when idleing. IAC will adjust bypass when engine gets warm making ECM happy.

Therefore you have to check TPS voltage and IAC settings.

Some numbers can be found in this discussion:

https://www.thirdgen.org/techbb2/sho...ht=MAF+voltage