Please be patient with me. I just started data logging with TunerPro (good job Mark!) and is there a lot of info to digest!! Hopefully I'll get my head around this soon. Please walk me through the first few steps. What I need is help knowing where to start making changes. I'm going to attempt to answer my own questions- so check me out and make comments/suggestions/corrections.

BTW- 89 IROC 5.7 T5 HSR 22# inj. 212 cam headers etc- $6e 165 MAF setup. Custom chip so I don't really know what it started out as. ARAP I think?!? The timing comes in like I would expect an "old school" distributer curve. 208 lv8 is 30'@2500, 32'@3000, 34'@4000+. 4-6' initial.

Anyway- everything seems pretty much in line. Getting a tad (1-3') of timing retard at times but the main value that out of line is the BLM's. When crusing I get anywhere from 132-140's. That means I'm programmed lean-right? I believe that I should lower my injector constants a bit- right?

Also running 830-860 mv at O2 sensor WOT. I think I'm running lean here too. Lowering the injector constant will enrichen WOT- right? Running high 9's bpw at 3000 to 5500. That figures to 87% at 5500. I'm ok with that for now. Question. I have a wire hooked up to my O2 sensor from before (poor man's A/F) about 8' just coiled under the carpet. Could that affect my O2 readings and BLM's?

Assuming that changing the I/C "fixes" the fuel, then I should start to lower my timing in the SA table, lv/rpm where I get knock retard by the amount of retard - 1'- right?

Ok please tell me if I am on the right track or if there's a better approach a nube can take. All will be appreciated.

One more thing- This is friggin fun!

 

If you don't know the history of the chip, what was changed, why it's been changed, etc., then you might start off fighting yourself here. consider starting with a 305 5spd or vette 350 bin.

If you're NEVER lower than 132 BLM across the board (any rpm any load) then you probably can add a bit of fuel. Since your BIN is of unknown origin, you could be fighting against any number of things, such as a hacked stoich value, the injector sizes might be wrong, etc.; also check fuel pressure and such too. basically, make sure you are not tuning around a mechanical problem or tuning around a hacked bin that no longer meets your needs.

Everyone has an opinion, mine is that O2 mV are meaningless for determining AFR. I have posted a chart a few times over the years that shows a huge scattering of AFR values (measured with a WBO2) vs. the mV indicated from a regular O2. It's pretty much all over the place. Tuning non-stoich AFR against the NBO2 can have you chasing your self in circles.

Yes, lowering the injector constants will increase the pulsewidth.

As for affecting your O2 readings, it depends what you are reading them on, but as long as your wire is not grounding on anything and you are using a high impedance meter (almost all digital meters are) then you should be fine.

if you are getting genuine knock retard, you've got too much timing. Rarely will you see only a degree pulled out. Search the archives here and do some reading on knock, but the short short version is that knock takes "time" to develop (it is not an instantaneous phenomena), and once it's started, you have to pull out a lot more timing (usually 3+*) to get it to go away. It's better to run at least a degree shy of a timing value that will cause knock, because you'll lose a lot more than that one degree when it goes into knock retard. Plus, it gives room for a tank of so-so gas or heat soak or whatever. finally, make sure you're getting real knock, not false knock. Depending on what heads you have, you may not need to push the timing anyways. some of the old design heads loved timing, modern heads (vortec designs, for example) just don't make any extra power with the extra timing because they don't need it, the chamber is just plain efficient enough that it doesnt need the extra lead time.