I am running an obd-0 LS(pr4) ecu with V-afc on my b16a engine and my a/f guage reads all the way lean. Does anybody think I am running lean because of the LS Ecu? or could it be something else?

 

does the a/f guage lights bounce around at idle/light throttle?? If not then its hooked up wrong. if yes then what are the VAFC settings?

 

Are you running modified fuel and timing maps for the B16 on your PR4, or are you using a stock ECU tuned for a low power LS?

If you're running modified tables, did you change the multipliers to that of a PR3 (The OBD0 VTec ECU)? This would cause major fouling of injector pulse duration. Basically, running you lean due to the B16s need for more fuel and air. Especially during VTec.

You should really be running PR3 maps on your PR4 and tuning from there. And since the PR4 doesn't have a high cam, and low cam map, you would need to tune the single (First ignition and first fuel maps since the PR4 has 2 ignition, and 3 fuel maps) map below your VTec crossover RPM with that of the PR3 low cam (with multiplers) and above the crossover with high cam. This way, you're getting proper fuel and ignition values.

 

actually i found that if you use a PR3 ECU you need to run the JDM o2 sensors or the pr3 ecu with the USDM LS o2 sensor thinks it runs lean as hell so it dumps as much fuel as possable. may be the same with the pr4 or the o2 sensor is toast.

 

Interesting idea, but... he's running a USDM PR4. So, natrually a USDM single wire O2 sensor with v0-1 signaling wuld be the appropriate O2. Using one on the PR3 would be the exact same. They're both OBD0. The PR3 just has VTec activation, VTec oil pressure, knock sensor, and lo/cam fuel and ignition maps. Everything else is the same. Also, if he were leaning in open loop, then that would also tell you that it is not an O2 related issue. So don't understand the logic behind using a JDM O2 sensor, could you explain it a bit more?

 

I just did my emmition test with a standard USDM o2 sensor and it was tellign the ECU that it was running way lean, so no problem i went out and bought another one and the same ducking ----. i was pissed at taht point and figured what the hell, its gato be a damn JDM o2 so i had one laying arround and that solved it and hte car passed W/O a problem. there is a diffrence, its shaped diffrent, hell the ends are even diffrent adn they drop diffrent voltages at operateing temps. so there IS a diffrence belive it or not. it enough of a diffrence taht the ECU thought it was running lean constantly and it was putting as much fuel as it could in the engine causeing it to fail but going over 3X the limit of hydrocarbons and way above on co levels. just an interesting little tidbit of info.