86 OBD code 42 & 36
Thread Starter
Advanced
Joined: Jan 2007
Posts: 50
Likes: 0
From: Columbus Ga
86 OBD code 42 & 36
Car is throwing codes 42 and 36. I am making the assumption that the MAF and ECM are bad. I have checked the connections, and they appear to be good. My problem is trying to decide what to do. I have been told that I can increase the horsepower by replacing a "chip." Note sure what chip. I am also unsure about the ECM. I have read where I must pull the PROM out of my current unit, and install it in the new unit. Can I get a new PROM and ECM? I also see where I can replace the Distributor Control Module. If any or all of these will/can increase the horspower, I would like to do this. I just do not know enough about these things to make a sound decision. Can anyone else me?
Safety Car
Joined: Jan 2004
Posts: 3,556
Likes: 13
Custom chip only needed if you have done other engine perf mods like heads and cam
Only source of a prom would be aftermarket ; either stock or custom tune depending on what other mods you have.
Replacement ECM would prob be rebuilt or used
Any 86-89 TPI car ; Firebird or Camaro, 305 /or 350 all used the same #'165 ECM as your car.
Only difference is the tune which is on the memcal (prom ) that you swap into a replacement ECM
Thread Starter
Advanced
Joined: Jan 2007
Posts: 50
Likes: 0
From: Columbus Ga
So your suggestion is to go with a remanufactured ECM. Found on on http://www.parts123.com/parts123/yb....rt~A2~cadefibF. Item #304576. This site also has a distributor control module that I am thinking about replacing. The car is actually running fine, it is only throwing the codes. By the way, I have made no modifications to the car. I am actually attempting to keep it as original as possible.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
99% of the time the code 36 is a bad MAF burnoff relay. It's located on the firewall behind the battery, along with the MAF power relay. Just replace both of them. They are very cheap and not worth trying to troubleshoot or play around with trick fixes. Be careful to get the right relays and get them plugged into the correct connectors. In 1986 the relays are different inside but the connectors are the same so it's easy to get them reversed. Yours might already be reversed, which will result in the code 36 but it takes several months for it to show up when the burnoff function is not working -- it takes a while for the MAF wire to get gunked up and stop working correctly.
10094701 --- AC Delco 212-305 --- Relay, MAF burnoff
10067925 --- AC Delco 212-300 --- Relay, MAF power
The code 42 is another 99% problem. When you open the EST connector to set the timing it will set an error code 42. You need to clear the ECM error codes to make this one go away. Open this connector for a second or so:
10094701 --- AC Delco 212-305 --- Relay, MAF burnoff
10067925 --- AC Delco 212-300 --- Relay, MAF power
The code 42 is another 99% problem. When you open the EST connector to set the timing it will set an error code 42. You need to clear the ECM error codes to make this one go away. Open this connector for a second or so:
