MMCD o2-r voltage on a 1990 ECU

[And_44]

Hello,

I've been searching going onto 3 hours and my eyes are hurting from the reading.

I have a 1992 Talon TSi. I have a 1990 EPROM ECU that's been installed in it. Brand new o2 sensor, and a 3" GM maf with translator. MBC set for 10psi.

Well, I've been using my Palm with 1.8g MMCD installed to log my car while I try to adjust my Maf-t. Yes, I know reading the o2 on the logger isn't as good as a wideband but I'm just using it as a "soft" tune to get things adjusted to work decently.

The o2 voltage usually in a WOT pull is sitting at .8 to .82 it will rise up to slightly over .9 only when letting off the throttle to go to idle.

My search's have led me to find some posts saying that with a 1990 ECU that the o2 voltage can read .1 off from what it should be.

So I would like some confirmation about this. Does a 1990 ECU read o2 voltage at a different voltage then later years?

When tuning the maf-t should I just be concerned with my fuel trims and knock?

Thanks for any input it would be greatly appreciated.

Drew

 

[steve]

My search's have led me to find some posts saying that with a 1990 ECU that the o2 voltage can read .1 off from what it should be.

So I would like some confirmation about this. Does a 1990 ECU read o2 voltage at a different voltage then later years?

Each car is different and you can't compare one to another but yes 90's read different that 91+ cars. Not that either is right or wrong.

Since the only thing that matters with a narrowband sensor is if it switches at 14.7:1 and how quickly, you can't really use it for WOT tuning unless you have some idea of the real AFR is for whatever it reads.

Get your fuel trims in good shape and save the rest of the tuning until you have a wideband.

 

[And_44]

Thanks Steve. Will do.