Closed-Loop Knock
Posted: Mon Mar 12, 2007 4:23 pm
I know it helps a lot to have a log of things like this, but all I've got is what the ScanMaster told me, so bear with me. My TMO datalogger is an hour away.
I've been tracking down little issues ever since my fudged race motor build. So far I've fixed the horrible idle, the sputtering exhaust, etc. What I'm looking at now is the constant yet random knock counts I get while cruising down the road with the TPS between 25-48%.
It seems to happen more often than not when the car is going up a hill. The knock counts haven't been alarming, usually somewhere between 1-8 counts, but every now and then it'll hit 15 (or those faux knock counts I see on it every now and then like 83 or 128). The O2's ramp up and down as per usual, and the only way to make the knock go away is to either give it enough gas to get the O2 voltage constant or let go of the throttle until the TPS is under 25%. WOT pulls give me a steady .94-.96v and 0 counts of knock all the way to 7,000.
I know it's not a huge threat to my motor, but I'd like to take care of it so the ScanMaster will quit bugging me. I've got poly motor mounts and a meticulously cared for motor. The only thing I can think of off the top of my head is the spark plugs being gapped incorrectly. It's almost time to replace them anyways so I'll pick up a set Wednesday to see if it helps. Any other thoughts?
I've been tracking down little issues ever since my fudged race motor build. So far I've fixed the horrible idle, the sputtering exhaust, etc. What I'm looking at now is the constant yet random knock counts I get while cruising down the road with the TPS between 25-48%.
It seems to happen more often than not when the car is going up a hill. The knock counts haven't been alarming, usually somewhere between 1-8 counts, but every now and then it'll hit 15 (or those faux knock counts I see on it every now and then like 83 or 128). The O2's ramp up and down as per usual, and the only way to make the knock go away is to either give it enough gas to get the O2 voltage constant or let go of the throttle until the TPS is under 25%. WOT pulls give me a steady .94-.96v and 0 counts of knock all the way to 7,000.
I know it's not a huge threat to my motor, but I'd like to take care of it so the ScanMaster will quit bugging me. I've got poly motor mounts and a meticulously cared for motor. The only thing I can think of off the top of my head is the spark plugs being gapped incorrectly. It's almost time to replace them anyways so I'll pick up a set Wednesday to see if it helps. Any other thoughts?