Anybody know what difference running a P13 ECU (OBD2) would have on a 98 H22 versus the 98 P5M ecu, specifically with respect to the fuel mapping?

I know the timing values are off by one degree. I am just wondering because when I run a P13 ECU, every once in a great while I would get a CEL for the knock sensor. It occurs during the following conditions:

- Shift into 5th gear just before 55 mph with gradual acceleration up to a cruising speed of 65-70 mph
- Low load...No headlamps, climate control off, radio on

I use premium fuel, spark plugs are good, no vacuum leaks, and EGR functions normally. Perhaps the P13 causes a lean condition under certain engine speeds and loads? Anyone know for sure?

Mods: Please move this to the Prelude forum.

 

p13 is OBD1 and p5m is OBD2. When going to OBD1 you'll need a conversion harness so that you can plug it into your 98 Prelude. Also, when going to OBD1 you'll need to have it chipped and tuned so that it'll work correctly and have your car running right

What type of mods do you have? Are you just running a stock p13?

 

I'm running the very rare OBD2 P13 ecu, but switched to the P5M since I have to get my car BAR'D (H22 in CD7 Accord). My car is pretty much stock with the exception of an AEM intake, which I will remove before going to the ref.

 

A knock sensor code is only caused by a problem in the knock sensor circuit. Or ECU. A lean condition or any other will not cause a knock sensor code. The P13 OBD2 ECU is out of a non immobolizer 96 lude. A rare ECU indeed.

 

did you figure it out. I have 96 prelude, running a h22a4 same issue p13 A12 obd2 knock signal not detected, I have ran a wire directly to the pin same result. Help if you can.