| Thought I'd post this for the archives... |
Subject: Thought I'd post this for the archives... by jsavoy on 2007/1/5 1:41:11 [size=13:ef0e518ae9][font=Times New Roman:ef0e518ae9]Below are quotes from another forum that answered my original question concerning the cause of my DTC P300: [color=darkred]"On a '96, you'll need to have the parameters for the misfire rpm changed (or the idle raised to ~850rpm) to avoid setting a misfire code (P0300). I bumped the misfire tables in mine such that the min rpm it looks for misfire is 1500 rpm. Btw, '96 is the *only* C4 that has this issue because it's the *only* C4 that has OBDII. Another poster mentioned "misfire code" in conjunction with his '95. '95s do not have the capability to set this code (not OBD II, no crankshaft position sensor, etc)."[/color:ef0e518ae9] Why would it register a misfire? Is that caused by the idle loping or spitback at low rpms? "[color=darkred]Technically either could cause it....a cam with a lope or a poorly running engine. To detect misfire, the PCM looks at the acceleration and deceleration of the crankshaft via the crankshaft position sensor. Every time a cylinder fires, the crank accelerates and between cylinder firing, there's a small deceleration of the crank. When the boundries programmed into the software are exceeded, the PCM cries misfire. By raising the rpm, you get away from the "lope". Conversely, if you like the lope then change the misfire detection rpm so the PCM doesn't look at the info until the engine is at a higher rpm."[/color:ef0e518ae9][/font:ef0e518ae9][/size:ef0e518ae9] |
