Spark Knock

Bear80

 
Joined
Sep 23, 2004
Messages
3,020
As I have been driving the 80 while installing my new lift for the mini, I have noticed a very annoying spark knock. It never spark knocks pulling up a hill or on sudden applications of throttle. The spark knock only occurs when you barely apply throttle to keep up a moderate speed, for example 30 mph or so.

As a side note, I also noticed that my rpms drop right back to idle when I lift off the throttle regaurdless of low or high rpm and when I go back to lightly apply throttle it knocks. It seems the computer is not or cannot do anything about it. If I apply more throttle it stops. I'm thinking my issue with the rmp's dropping down is part of the problem. As I know my 22r and 3vz use a "dash pot" (?term?) to keep the rpm's from falling to fast when you lift off the throttle. I'm sure this is the same on the 1fz but anything else I should maybe look for?
 
Last edited:

powderpig

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Jul 12, 2005
Messages
1,026
Location
Boulder Foothills, CO
Hook up a OBDII reader/computer program(they have been discussed in other threads) and take it for a drive see what is happeneing that may still be in the paramiters but not triping a code. Yes there is a dash pot on one side below the cables. May be looking for light throttle lean condition. May jsut want to check and adjust the throttle position sensor. good luck robbie
 

Bear80

 
Joined
Sep 23, 2004
Messages
3,020
powderpig said:
No hand held code reader, you need some real time data logging, like a computer based or OTC, snap on, screen based data reader. late robbie
Well that pretty much puts it out of the question. :frown:
 

tarbe

 
Joined
Aug 6, 2004
Messages
1,499
Location
Houston, Texas for now - Romance, MO soon!
I have the exact same deal. Only goes away with 91 or better octane. I'm finishing up a tank of Chevron Supreme 93 right now and it has been nice not hearing that dang noise the past 10 days.

I've run BG-44K, Schaeffer's Soy Ultra, Marvel Mystery oil, Seafoam (in the tank, not up the PCV) trying to clean out the carbon I suspected was the culprit. I am chicken to do the water treatment...plus I wonder now if it is carbon or something in the management systems.
 
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