How does the PCM determin a misfire?
06-14-2007, 09:40 AM
#4
TECH Regular
iTrader: (14)
Join Date: Oct 2005
Location: Dayton, Ohio
Posts: 437
Likes: 0
Received 0 Likes
on
0 Posts
I have a #6 cylinder misfire that I can't figure out at idle (goes away above 1,200RPM), changed plugs, wires to no affect. It could be the coil but who cares? Anyways, just for fun I disconnected the wire on cylinder #5 and and the PCM was counting misfires on #5 as well as #4. Food for thought
06-14-2007, 09:42 AM
#5
TECH Enthusiast
Join Date: May 2007
Posts: 538
Likes: 0
Received 0 Likes
on
0 Posts
It looks at the speed of the trigger wheel. Based on variations in the speed of the wheel on the crankshaft it determines if it has a missfire. it looks for oscilation in the pattern.
