AFR stays rich

[SS2win]

So I have a bit of a problem with my step daughters 1995 Z28. It's 24x converted LT1 with a P01 PCM and 6125 OS that runs really rich. It has no MAF so I've set it up as SD and when trying to dial in the VE, I get reasonable correction numbers but once they are applied, the tune dives back to 10-12:1 everywhere. Anyone have any tips for what to look for? I think I'm in over my head!

[nonnieselman]

Is your injector data correct?
Ive never done that kinda swap so just my first thought was injector data..

[SS2win]

They are the unknown factor. Bosch with the numbers marked off and what looks like flow rate burned into the body. good point

[SS2win]

I've been searching for a post that described verifying the injector data but having no luck. anyone remember this and have a link?

[Doc]

You have to consider that if you do not have the truth at KOEO, that is, 1) Fuel pump primed and pressurized to commanded. 2) Valid MAP/Baro scaled to your elevation. 3) Valid Displacement and Injector Data you are going to be shooting fish in a barrel. Xmas has come and gone, New Year's gift to your son and daughter-in-law, numbers matching, traceable injectors would cut to the chase if you can't get rational, repeatable performance out of the injectors you have?

[SS2win]

Yes for sure. We are already on that ... but not before trying a bunch of alternate injector data to see how the system responds. No matter what we do, everything works kinda opposite from what I'd expect, lean (17:1) at cold start up gradually going rich (10:1), it leans out when you tap the throttle then returns to rich. Crazy? yes. There's a lot of mods to the engine management I don't like so we're going to do a full wiring audit, put the MAF back in and replace the O2 sensors which are currently showing 0-45mv swing. Anyway, I was kinda hoping for an easy answer here! haha

[ChipsByAl]

Make sure the O2 sensors are not switched from bank to bank. I have seen it several times and causes some whacky issues. Easy to test, just disconnect one and expect it not to swing voltage.
Al

[SS2win]

Yeah, wow I can see that causing crazy issues! Thanks

[statesman]

Check your O2 sensor heater circuit.

[statesman]

Did you fix the problem?

[SS2win]

No man, she had to go back to school. Hoping we can work on it during spring break...

[SS2win]

Alright! It was spring break last week, we did a bunch of work on her car and found it was the injectors. case closed!


24093

[Doc]

Good on ya for taking the time to post the resolution. Hopefully it helps some other soul.

[joecar]

Good job. Thanks for posting.