02 delete

[jkeaton]

Back to the PCM compatibility then.

 

[Trstrugar]

Possibly. the guy I bought the thing off of swears up and down that it's comparable. He used a 95 obd1 Tahoe engine. And kept the old pcm and wiring harness. The thing honestly runs fantastic aside from start up and idle. It runs so rich when you first start it up you get a cloud of black smoke from all the gas burning, but after that it runs pretty solid. Will occasionally bog down at red lights.

Is it possible that without the cats and with open headers like that, one of those mechanical o2 sensor simulators could make the difference?

 

[Trstrugar]

Jkeaton I really appreciate all of your input and help, I know I've been posting about this for a couple of days now lol

 

[jkeaton]

No worries man, these kinds of things are tough to diagnose over the internet.

 

[Justin S]

Is the oxygen sensor you installed a 1 or 4 wire?

 

[Trstrugar]

It is actually 3

 

[Trstrugar]

I did a bit of research on this and it appears this is how some of them came. It is rare but the 3 wire o2 sensors on this particular truck are located underneath the passenger side of the truck

 

[Justin S]

maybe its a california emissions thing, idk. Since you have more than 1, you will need to get a wiring diagram and see which one is supposed to be power, ground, and signal and make sure they are right.

 

[Trstrugar]

So I am no longer throwing any o2 codes. Interesting, the computer doesn't seem to care about the o2 sensor anymore after I fixed the wiring on the IAC. Rewiring that re solved a lot of my issues. It still runs rough and sputters for the first 10 seconds, then goes up to 1500 Rpms but immediately comes down where it's supposed to be. I am throwing a code 33 for map sensor voltage high. I dont exactly know what the map sensor is supposed to do or if it is likely the culprit of this rough start up.

 

[Justin S]

voltage high code means its seeing a 5v reference with no resistance, as if its unplugged. either a bad sensor or bad wiring going to it. Map reads the manifold absolute pressure. Definitely would contribute to rough running