Ok, finally got another ecu to see if my p28 was shot. I got my hands on a chipped/converted p06, and now new problems have shown up. Below is a list showing every ecu I've used, and what happened when I plugged them in on my jdm h22a powered '93 prelude.

jdm p13 = had no issues at all, but I recently sold this ECU. No cels(this was before i ever bought the aem wideband).

usdm p14 = o2 CEL / runs rich / obviously no VTEC.

usdm chipped p28 j1 on(xenocron custom tune) = o2 CEL / fuel CEL / 3500rpm limit / af ratio is rich.

usdm chipped p28 j1 off(oem p28 maps) = CEL doesn't do it's 2 second cycle when key turned to "on" while fuel pump is priming. When started...o2 CEL / fuel CEL / 3500rpm rev limit / runs very lean.

usdm p75 = o2 CEL / runs a little lean / obviously no vtec

usdm chipped/converted p06 j1 on(same xenocron custom tune) = o2 cel / runs very rich / weird VTEC issues. Sometimes I feel VTEC kick in around 4800, sometimes it doesn't feel like it's kicking in around that rpm, and one time the car actually acted like the fuel was cutting off at 4800...I let off and got back in to the throttle, it revved up normally and I didn't feel anything around 4800rpm anymore.

It turns out that my p28 was shot, or at least the fuel test circuitry or whatever it's called was bad. The fuel CEL it was giving me was a false error, and was causing limp mode. Only the p28 did this.

So now that I have this p06, car runs lean and has weird VTEC issues. Does that sound like the tune is bad? Keep in mind that this car ran like brand new, no issues at all, on the jdm p13 ecu meant for this motor. All I've changed since selling that ecu...installed the AEM gauge-type stand-alone wideband controller & removed oem o2 sensor for the new bosch wideband sensor.