Reading high knock count
Thread Starter
Joined: Oct 2002
Posts: 523
Likes: 58
From: Winnipeg, Manitoba, Canada
Reading high knock count I have a very high knock count. It will roll over after 2 mins at idle. The numbers change so fast that its in the thousands within a couple of seconds.
This is what I've done so far:
Changed O2 sensors (they were old).
Running new NGK TR6 plugs.
New wires (burnt old set).
Drained gas and filled up from another station with the highest octane I could find.
Re-sealed Intake Manifold.
Changed the coil.
Disconnected the Accel ignition.
So it is not fuel related. My oil pressure is excellent. Exhaust smells fine...for an LE2 cam with no cats. It happens after the car goes into closed loop (5 mins idling).
The car will surge at idle and try to rev up to keep the car running. When I turn the car off, you hear a very fast metallic rattle for 1/4 of a second as if the timing is off or something.
While the car is in open loop, it sounds perfect.
This is a 93 so its not the MAF.
MAP sensor? Knock sensor?
My laptop's diagnostic software is corrupt so I can't scan it. I have an Auto X-ray as well which I have never used since I had the laptop.
I was running 91 octane last time, switched to 92 octane Ethanol blend, currently running 94 octane Ethanol blend which is the highest octane I can find.
Each time I completely drained the tank. Car always shows 0.1 or 0.2 degree retard on the laptop last year with a continuously rolling knock count. I guess I could check with the Auto X-ray as well.
Would a bad PCM do this? Somehow, I don't trust the last shop I was at. Found out afterwards that they mess up a lot of cars. They did exhaust work on my car. Maybe they fried the PCM somehow?
Suggestions?
This is what I've done so far:
Changed O2 sensors (they were old).
Running new NGK TR6 plugs.
New wires (burnt old set).
Drained gas and filled up from another station with the highest octane I could find.
Re-sealed Intake Manifold.
Changed the coil.
Disconnected the Accel ignition.
So it is not fuel related. My oil pressure is excellent. Exhaust smells fine...for an LE2 cam with no cats. It happens after the car goes into closed loop (5 mins idling).
The car will surge at idle and try to rev up to keep the car running. When I turn the car off, you hear a very fast metallic rattle for 1/4 of a second as if the timing is off or something.
While the car is in open loop, it sounds perfect.
This is a 93 so its not the MAF.
MAP sensor? Knock sensor?
My laptop's diagnostic software is corrupt so I can't scan it. I have an Auto X-ray as well which I have never used since I had the laptop.
I was running 91 octane last time, switched to 92 octane Ethanol blend, currently running 94 octane Ethanol blend which is the highest octane I can find.
Each time I completely drained the tank. Car always shows 0.1 or 0.2 degree retard on the laptop last year with a continuously rolling knock count. I guess I could check with the Auto X-ray as well.
Would a bad PCM do this? Somehow, I don't trust the last shop I was at. Found out afterwards that they mess up a lot of cars. They did exhaust work on my car. Maybe they fried the PCM somehow?
Suggestions?
Last edited by Gripenfelter; May 15, 2006 at 01:27 PM.
If you're only getting 0.1-0.2 of retard I wouldn't worry to much, unless you hear pinging or it runs badly.
You don't really want to look at knock count as much as retard.
With an LE2 it could very well be false. Run a tank of race gas (100+) and see if the behaviour changes any. If it doesn't, then you know it's not a big deal.
You don't really want to look at knock count as much as retard.
With an LE2 it could very well be false. Run a tank of race gas (100+) and see if the behaviour changes any. If it doesn't, then you know it's not a big deal.
Thread Starter
Joined: Oct 2002
Posts: 523
Likes: 58
From: Winnipeg, Manitoba, Canada
The knock retard doesn't really bother me. Its the surging at idle and the metallic rattle that I'm worried about. It happens in closed loop from what I can see.
Thread Starter
Joined: Oct 2002
Posts: 523
Likes: 58
From: Winnipeg, Manitoba, Canada
The rattle only occurs when you turn off the car. You hear it about 0.25 to 0.50 secs after you shut off the ignition. It sounds like timing is way out.
Tune was done by PCMforLess and the car ran fine before it went to a certain speed shop that refuses to fix it.
Its not a vacuum leak because I've re-sealed the intake and checked all the lines.
Tune was done by PCMforLess and the car ran fine before it went to a certain speed shop that refuses to fix it.
Its not a vacuum leak because I've re-sealed the intake and checked all the lines.
Thread Starter
Joined: Oct 2002
Posts: 523
Likes: 58
From: Winnipeg, Manitoba, Canada
Update: Disconnected the knock sensor. No effect. Car still tries to die.
It sounds normal at 1100 rpm and higher. When it drops down to 500 rpm (in park) it sounds like marbles in a can. If you rev it up it sounds fine.
Isn't not being able to maintain idle a symptom of a bad PCM?
It sounds normal at 1100 rpm and higher. When it drops down to 500 rpm (in park) it sounds like marbles in a can. If you rev it up it sounds fine.
Isn't not being able to maintain idle a symptom of a bad PCM?
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Thread Starter
Joined: Oct 2002
Posts: 523
Likes: 58
From: Winnipeg, Manitoba, Canada
I found a .uni file (datamaster) from last year when I started having this problem.
http://members.shaw.ca/fbody_god/Gripdiag1.uni
Note the timing, rpm dip, and knock count. Bad knock sensor? Bad MAP? Or bad PCM?
http://members.shaw.ca/fbody_god/Gripdiag1.uni
Note the timing, rpm dip, and knock count. Bad knock sensor? Bad MAP? Or bad PCM?
