Hi All, first off I just want to say thanks to everyone who participates here. Such a great site with a tremendous amount of info and help to guys like me who are newer to these cars and their nuances. Hopefully as I gain knowledge I can also be helpful. Here's my issue. I've had my manual 87 Iroc with 305 LB9 tpi engine about a year. I was getting an intermittent error code 33 initially which seems to relate to possible faulty wiring, the MAF sensor or it's relays. In trying to fix this I replaced the burnoff sensor relay and the MAF sensor today with a new Delphi one which is actually same as the old one but new. The MAF burnoff sensor harness looked really bad upon inspecton so I cleaned it up as best I could before installling the new sensor, cleaning contacts and taping exposed wires and it looked much better. Upon restarting and ECM relearning the car initially seemed to be normal and began idling at 750 as usual after several minutes. I took it for a short drive and after a few minutes up popped the SES light and the car began running poorly. I pulled over, checked it and it was a code 45 indicating a rich fuel condition. I forgot to mention I did also replace the injectors with new correct Delphi ones a couple of weeks ago as rhe Mastecs were old and ticked loudly and these new ones have operated fine, quiet with no leaks or visible problems since. Any idea what might be the source of this new code 45? Also, I thought the MAF power relay was in the same location on the firewall but is isn't there. Where might this be located if not here? Could this code 45 be harness related? Any input is greatly appreciated.

Maf burnoff harness

Maf burnoff harness
[img alt="Couldn't locate the MAF power harness among the others here. The 2 on the right are newer, fan related.
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Couldn't locate the MAF power harness among the others here. The 2 on the right are newer, fan related.

 

Code 45 or 54 ?

 

Code 45 is what it's showing.

 

A rich condition wouldn’t be caused by your fp relay pigtail being messed up.

 

Ok, good to know. I thought this was the maf burnoff relay but it's actually the fp relay. Where would the maf relays be located, any idea?

 

are you fighting a code 33 or 36 seems like we are jumping all around on this thread

 

Hi, apologies for any confusion. Initially was getting a 33. Thought I had changed the Maf burnoff sensor relay and was also going to replace the maf power relay. Seems I have put this new MAF burnoff sensor relay into the fp harness which is likely causing this new code 45 as it's the wrong sensor. Can't seem to locate the Maf sensors on the firewall though as there aren't any other visible 5 pin connectors. I found an old post of yours that included the attached LB9 relay locations but it doesn't seem to match up with my setup as the 5 pin maf relays don't seem to be where they should be. Maybe it is different for 1987.

So, that's where I am at present.

 

not sure what the aftermarket relays are being used for. You wire colors may vary I don’t have a fsm for your car. Have you used the fsm troubleshooting tree to diagnose the code 33 maf high ?