When I fist start car for the day engine light comes on. After car is warmed up and started later light is off. Then as car reaches proper operating temp engine light comes back on and I lose idle, erratic shifting, over all performance. The error code from the ALDL shows code34 maf sensor.
Does anyone have any ideas of what else could cause this error, and how to test the maf sensor? I can't find any visual problems.

 

you can get an ohm reading on it somehow.... and blow air through it at the sametime.... i think they are pretty cheap.... just don't buy autozone crap.... they worry about selling toys and not parts....

 

They are very expensive. I think about 160 for an autozone brand and upwards of 350-400 for an AC Delco unit. It could be the Maf, Maf power relay, or the Maf burnoff relay. Get yourself a TPI swapper guide book and it shows you step by step on chasing down the problem through various pictures and diagrams.

 

look at my thread (maf +02), vader has a wiring diagram, Test the output when idling etc

hope helps

 

Cross your fingers it's the maf on an '85. You don't want to replace the little box (MAS module) under the pass side kick. WAY more than a MAF... IF you can find one (unless something has changed lately).

Now, that said, IIRC the 85's had a problem with false MAF codes and one of the things was to get an updated PROM... hold on...

The updated prom chip should have a silver sticker on it with HLM 3800 on it. If not, you probably need a chip (IIRC ~$50).

The diagram, and MAF itslef, is different on an '85 than an '87.

 

woops, sorry didnt realize you had an 85, Sorry if i confused you

 

i know when i got the mass air sensor code, i changed it 3 times in two months because it kept saying it was bad. then i did a tune up and found out my plugs and wires were bad and i havent seen the code since i did that just putting my two cents in

 

I there also does'nt seem to be maf burnoff relay,it should be by my fuel pump relay and it's not there. Also there is no other wires or connctors laying around .I have looked at varies wirring diagrams they show one should be there unless they are for another year.

 

Thanks for the info, I'm going to have a look at those items. Parts up here are almost impossiable to find especialy electronic parts that are actualy the right part number.

 

No, it (relay) should not be by your fuel pump relay. It does not exists on that car as such. It is part of the MAS under the pass. side kick.

If you are hurting for parts, convert to a SD system. The ecms are relatively abundant in a few other gm models and there are instructions on line and some members who have done it.