Error code P300

Has anyone ever gotten this code after a 6 bolt swap bolted to a 2g head in a 7 bolt car?

 

[atc250r]

That's a misfire code. I think its common with 6 bolt swapped 2G's. Sorry, that's all I know about it. Check the VFAQ, I think they have info on it.

John

 

300 is random multiple cyl misfire. 301 cyl one & so on.

 

That's one big reason my 2G chips are so popular, they fix the Random Misfire MIL. You can also do it by lowering the BARO voltage with a pot until it is below the threshhold where the ECU will check for a misfire, as per Magnus' site. /ubbthreads/images/graemlins/wink.gif
See page #10:
Magnus 1G-in-a-2G

 

Thanks. I checked vfaq but no mention of it or how to go about solving it.

 

Thanks Jeff.

 

[iceman69510]

I think misfire detection is accomplished by the ECU measuring the crank angle sensor rotation against the CAS rotation. If there is a difference, it assumes misfire.
Thus, if the crank angle sensor is no longer there, it can't do this.

Jeff, what signal do you manipulate to eliminate this, the baro sensor like you said or something else?

 

[jepherz]

He probably just changed that threshold on when to check for misfire.

 

If you read the Magnus link, you'll see that the ECU bypasses the Misfire Check if several sensor parameters aren't met. The easiest one to manipulate, without causing other MILs or issues, is the BARO. You can run the voltage just far enough out of spec for the Misfire Check to be bypassed without causing an MIL for the BARO using the pot. However, this also leans the AFR out slightly, which can cause issues. So, I simply change the code to ALWAYS bypass the Misfire Check. /ubbthreads/images/graemlins/wink.gif