Who has Tuned with no NB02s?

[SilverJester]

I don't know why people think 1Gs don't throw CEL for o2s. Both my '92s have done it.

Well I`ve done 2 years or more with no o2 near the car and no CEL.. Must be ECU specific.

Yeah it would be interesting to figure out why some 1g don't cause a CEL and other do. Mine doesn't throw a CEL, but I forget what yeah my ecu is from (I had t replace my original one cause the caps went bad).

[RL7]

Have you logged your AFRs before and after the CEL to see if there is any noticable difference? It is likely that the ecu uses a different fuel and timing map in "limp mode". I would suspect that it would run richer with less advanced timing. If this was the case, you would want to re-tune after the CEL was thrown if you were going to run this way. I'm running a 91 car with a 95 engine and a 93 ecu and I have no CEL with the O2s removed. I do have slight knock (usually 1-3 counts) right around 2k rpms under low throttle. Right now, I'm running a pretty safe map that is rich across the board. I tried to richen it up more at the 2k light throttle area and it didn't solve the problem (it may have reduced it though). I'm starting to suspect that it may want to be right around stoich there for whatever reason. I'll probably try to lean it out there to see what happens.

Which maps are you using with the e-manage? I use the Injector, the MAF correction, and the "Acceleration" map. I try to keep most of the corrections to the Injector map to minimize any unpredictable modification to timing. You can't put any negative values on that map though. You may want to juggle corrections from one map to another (if possible) to see if it has any effect.

[HLxDrummer]

Ya, my AFRs are the same. MAYBE .1 AFR off. I thought it would richen it/retard timing or not do anything but I'm lost at this point. I actually leaned it out a bit where it was having trouble and it helped a little. Still can't give it the throttle I can with the stock O2s without getting a ton of knock though. With stock O2s I get a few counts here and there like you.

I'm using MAF correction and ignition. I don't have the injector stuff hooked up but maybe down the road I will.

However, I'm almost positive it has something to do with the CEL. As soon as the light comes on it starts knocking under high load/low RPM but when the light is off I have no problems, actually less knock than stock. I would love to eliminate this problem without adding more crap to my car but I may have to just buy an O2 simulator.

[RL7]

Probably a dumb question, but did you read the CEL to make sure it was for O2s and not something else?

[HLxDrummer]

Ya I did check Was hoping it would tell me specifically what about the O2 threw the code but no luck.. Thanks for all your help by the way!

[mh3kgt]

Yeah, I'm 1g here (92) and I don't get any CEL's from my O2's being unplugged with maftpro. Interested to see what is causing your knock issues tho

[HLxDrummer]

Man, lucky you guys!

What else does the ECU control that could cause this? According to the wideband AFR is constant, according to the logger timing is constant, boost is irrelevant.. IAC? I have a steady AFR though so that shouldn't matter..

[RL7]

Are you logging the wideband with the datalogger? I don't have an accurate gauge, so I have to do this, but I would probably do it regardless. It lets you see a lot of stuff that you may otherwise miss. For instance, with some of this knock, I sometimes see an instant 0.5-0.75 drop in the AFR, this leads me to believe it may be some sort of misfire. It's pretty easy, you just feed your wideband output into the EGRT pin on the ecu and set the software up to log that. If you are doing that, do you see the AFR doing anything even slightly suspicious when it knocks? You may just want to go nuts and kick it down to 10.xx at the knocking point to see if that does anything. It may be worth a shot to hook up the injector stuff and play with the Accel map. I'm not sure if it actually does what it is supposed to do, but it does seem to good a good job of keeping the AFR pretty level. It is extremely baffling that the timing and AFRs stay the same and it knocks only once the CEL comes on. Mabye take an identical drive before and after and post up the logs of that particular point?

[HLxDrummer]

I actually have it feeding into my Scanmaster 3, but haven't logged it. Good thinking though, my AFR does jump around some and it could correspond with the knocking.

I would try making it way rich but I think that may make the problem worse with all that fuel. I've gone down to 13.8 AFR, however, and no big difference. 4* retard doesn't make a big difference either.

I can post logs if you think it will help. I'm pretty sure it corresponds with the CEL, but I guess it would be nice to see what the ECU is doing to cause the knock, huh? Maybe making it overly sensitive? I'm not familiar with what the ECU can/will do..