no, i only get SES if i hold higher rpm @ idle in park for extended periods. i had to work at it too get code to set. should take my own advice and replace plugs, the current ones look ok but i didn't install them so you don't know if they've been dropped or overtightened and porcelain has a hair line crack. drivebility seems ok, i should disconnect knock sensor and datalog to see if i'm still getting counts....
Last edited by tayto; 09-14-2021 at 06:45 PM.
I finally got a chance to do some data logging tonight. 27K knock counts in about a 10 minute drive. Watched the whole datalog so at least I know it didn't turn over in that time frame. So it's less than it was before I put new plugs in and tightened stuff, but still significant. I'm getting a lot of knock retard in the 3 deg or less range, but also getting some up to 10 deg in heavy accel or load. And it was showing 3 deg on the freeway at steady 60 mph, no hill. (but it was only a mile on the freeway)Originally Posted by tayto
How do I know if this is real knock or it's just hearing something mechanical? Truck has stock L31 valvetrain (roller lifters) and also Comp Cams stamped steel roller-tip lifters. Would either of those cause noise?
In your case, how would it register any knock at all if the KS is disconnected? (Not being a smart ass, I just want to know) Should I do that test?
One last question, I have PE turned off for narrow-band VE tuning. Should I turn it back on? Maybe a lean condition during accel is causing knock? I'm about to switch to WB tuning so I think it should be on anyway for that?
mine wasn't registering knock with sensor disconnected. If it was i would suspect ECM. I worked on a '727 swapped into an older car that was running funny. found if you tapped the ecm case it would detect knock. replaced ecm and problem went away.
How do you know if it's real knock? Put high octane fuel in and pull all the timing. It won't make much power, but it also won't knock. If it says you're knocking anyway, it ain't real.
1990 Corvette (Manual)
1994 Corvette (Automatic)
1995 Corvette (Manual)
I'll try that - eventually. I just put $100 of 87 octane in, as I was pumping I realized I should have put in 93 to see what it does. But I am going to pull timing and see what that does. I found this thread with the '98 vortec timing tables. They are all lower values than the ones in my BIN, up to 7 or 8 degrees. My engine is a 9.5:1 vortec 383 so I'm going to see what happens with those timing values.
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