Could be knock sensor. Ive never had a knock at idle ,only on acceleration.
L98 Spark Knock Issue. HELP!
Thread Starter
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Joined: Sep 2007
Posts: 97
Likes: 0
From: Wixom Michigan
L98 Spark Knock Issue. HELP!
Anyone who has dealt with this or may have an idea please post.
Background: An 85' 4+3 with 62,000 original miles. I have owned it for only 2000 of the miles. The car is bone stock other than a new exhaust with no catallytic converters on it.
The PROBLEM: At idle I BELIEVE I'm getting spark knock and I'm not sure where the problem lies or how to change it.
What I've Done So Far: Changed the cap, rotor, plugs, and wires. Checked the timing and it was at 0 degrees TDC. Took a timing light and changed it back to the manufacturers rating of 6 degrees BTDC. Seems to run much better, however, the spark knock still persists.
Any ideas to you Corvette gurus out there?!?!?!?
Thanks in advance!
Jim
Background: An 85' 4+3 with 62,000 original miles. I have owned it for only 2000 of the miles. The car is bone stock other than a new exhaust with no catallytic converters on it.
The PROBLEM: At idle I BELIEVE I'm getting spark knock and I'm not sure where the problem lies or how to change it.
What I've Done So Far: Changed the cap, rotor, plugs, and wires. Checked the timing and it was at 0 degrees TDC. Took a timing light and changed it back to the manufacturers rating of 6 degrees BTDC. Seems to run much better, however, the spark knock still persists.
Any ideas to you Corvette gurus out there?!?!?!?
Thanks in advance!Jim
Thread Starter
Advanced
Joined: Sep 2007
Posts: 97
Likes: 0
From: Wixom Michigan
I'm running nothing but premium and have run premium since I've owned the car. Even ran some fuel system cleaner through it.
I have not yet scanned for codes. Wouldn't I be getting a Check Engine Light if something internally was wrong?
I have not yet scanned for codes. Wouldn't I be getting a Check Engine Light if something internally was wrong?
Le Mans Master
Joined: Aug 2007
Posts: 8,735
Likes: 412
From: WV
Pro
Joined: Nov 2006
Posts: 638
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From: Plano TX
Well, here's a handful of things to check...
-- Are you over heating any at all?
-- Is the EGR functioning correctly?
-- Is Fuel Pressure good?
-- Are your valve seals good?
-- Have you tried changing gas stations just to see?
I pulled most of that stuff out of my FSM just to give you some suggestions.
-- Are you over heating any at all?
-- Is the EGR functioning correctly?
-- Is Fuel Pressure good?
-- Are your valve seals good?
-- Have you tried changing gas stations just to see?
I pulled most of that stuff out of my FSM just to give you some suggestions.
Drifting
Joined: Apr 2007
Posts: 1,339
Likes: 2
From: port charlotte fl
OOOH didn't think of that. Not teaching you to suck eggs but if you don't know stick a paper clip in the top two right hand holes in the ALDL (next to your right knee)switch on the ignition and the ses light should flash 12 three times,thats flash,flash flash.Then it will flash any stored codes.If there are any count them and post them here and we can tell you what the problem may be.
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Drifting
Joined: Aug 2007
Posts: 1,672
Likes: 0
From: Hereford AZ
Anyone who has dealt with this or may have an idea please post.
Background: An 85' 4+3 with 62,000 original miles. I have owned it for only 2000 of the miles. The car is bone stock other than a new exhaust with no catallytic converters on it.
The PROBLEM: At idle I BELIEVE I'm getting spark knock and I'm not sure where the problem lies or how to change it.
What I've Done So Far: Changed the cap, rotor, plugs, and wires. Checked the timing and it was at 0 degrees TDC. Took a timing light and changed it back to the manufacturers rating of 6 degrees BTDC. Seems to run much better, however, the spark knock still persists.
Any ideas to you Corvette gurus out there?!?!?!? Thanks in advance!
Jim
Background: An 85' 4+3 with 62,000 original miles. I have owned it for only 2000 of the miles. The car is bone stock other than a new exhaust with no catallytic converters on it.
The PROBLEM: At idle I BELIEVE I'm getting spark knock and I'm not sure where the problem lies or how to change it.
What I've Done So Far: Changed the cap, rotor, plugs, and wires. Checked the timing and it was at 0 degrees TDC. Took a timing light and changed it back to the manufacturers rating of 6 degrees BTDC. Seems to run much better, however, the spark knock still persists.
Any ideas to you Corvette gurus out there?!?!?!?
Thanks in advance!Jim
Pro
Joined: Mar 1999
Posts: 678
Likes: 0
From: Oslo, Norway
Hi I have also an 85 4+3.
If the timing showed 0 degrees a bell chimed. I had a bad balancer which has loosen from the rubber between inner hub of it and the outer metallring with the timing mark on. If you have the old one check that you have topdead center of 1 cylinder at the 0 mark. If that is wrong you have wrong timing and if the reason for 0 degree before adjusting it was a loose balancer you have now 12 degree timing and thats for shure making knocks. This is of course one reason there are as mentioned above many more
good luck
If the timing showed 0 degrees a bell chimed. I had a bad balancer which has loosen from the rubber between inner hub of it and the outer metallring with the timing mark on. If you have the old one check that you have topdead center of 1 cylinder at the 0 mark. If that is wrong you have wrong timing and if the reason for 0 degree before adjusting it was a loose balancer you have now 12 degree timing and thats for shure making knocks. This is of course one reason there are as mentioned above many more
good luck
Burning Brakes
Joined: Dec 2006
Posts: 936
Likes: 2
From: Tyrone PA
Hi I have also an 85 4+3.
If the timing showed 0 degrees a bell chimed. I had a bad balancer which has loosen from the rubber between inner hub of it and the outer metallring with the timing mark on. If you have the old one check that you have topdead center of 1 cylinder at the 0 mark. If that is wrong you have wrong timing and if the reason for 0 degree before adjusting it was a loose balancer you have now 12 degree timing and thats for shure making knocks. This is of course one reason there are as mentioned above many more
good luck
If the timing showed 0 degrees a bell chimed. I had a bad balancer which has loosen from the rubber between inner hub of it and the outer metallring with the timing mark on. If you have the old one check that you have topdead center of 1 cylinder at the 0 mark. If that is wrong you have wrong timing and if the reason for 0 degree before adjusting it was a loose balancer you have now 12 degree timing and thats for shure making knocks. This is of course one reason there are as mentioned above many more
good luck
I don't see how you could get spark knock at idle, but I'm no expert on these systems or computers. I would think the knock retard system would retard the timing if it were spark knock and the knock would go away. Maybe you can get someone with the right setup to check the knock counts while idling?
