Ideal AFRs? Rich after injector change.

[Fidhle007]

Very interesting... I'm going to have to see where my AFRs stand once my car gets back from the body shop and I can get over to the dyno. I think I've actually got some S52 injectors lying around. Pink, right?

Yep.

[Brew]

Very interesting... I'm going to have to see where my AFRs stand once my car gets back from the body shop and I can get over to the dyno. I think I've actually got some S52 injectors lying around. Pink, right?

[Fidhle007]

I'm now posting from the driver's seat of my car which is currently idling at stoich on the nose! It runs into the the 13s at high RPMs and may have a weird lean spot at 3500 but I think that goes away under load. It seems the secret to running a TMS 24# chip is to use S52 injectors...

[Fidhle007]

Hmm, well I have had no end of trouble with my 02 sensor (a problem that I could probably fix now that other people have run into the same issue) so my solution was to run the analog output of my LM-1 to my O2 signal and set it to mimic the stock 0-1v signal. So technically I have no O2 sensor anymore so what I'm seeing on the wideband should be what the DME sees too...

[Brew]

I'd think with afrs that low you would be maxing out the fuel trim adaptations (full negative) as the dme tries to compensate. Maybe your O2 sensor is sending the DME false signals?

[e30polak]

You will simply be making less peak power, then if you were to clean up the afrs.

[matt]

Better rich than lean.

[Fidhle007]

So am I hurting things by running rich? ADSS on sunday and HDPE on Thursday, I want to be in good shape for that...

[e30polak]

That's weird. There are adaptations that will take care of a lot of that though. And who's to say the TMS chip isn't programmed to be even richer than you were running?

Most guys on BFC, along with myself have experienced pig rich afrs with the 24# injectors+TMS tune.

[nando]

could it be a difference in injector characteristics? While they are usually pretty similar, injectors all have different response times and voltage correction curves. Maybe the opening time of the 21# injectors is shorter than the 24#s so it runs richer on the same PW.

[matt]

That's weird. There are adaptations that will take care of a lot of that though. And who's to say the TMS chip isn't programmed to be even richer than you were running?

[Fidhle007]

That's the thing, it's a TMS chip for 24lbers and Euro MAF...? So in theory I should have been running lean with the 21.5s and now things should be right but that doesn't seem to be the case...

[matt]

Unplugging the OBD1 ECU for even a half a second will clear its adaptations.

21.5s are fine up to 250whp. As long as your chip is programmed to match them.

[e30polak]

Yikes that's rich even for FI!

Word. You could run a dry-shot of NOS and be ok with those numbers lol.

BTW I have the TMS tune for the same mods and the AFRs suck. That's your main culprit, you'll see that when you put it on the dyno.

[z31maniac]

Yikes that's rich even for FI!