Knock Issue - At a loss? Need some advise.
#1
Knock Issue - At a loss? Need some advise.
Guys,
Here's my dilema. I am picking up knock on my PCM (seeing it thru Datamaster) and it's pulling upto 12 deg timing. Now I cannot hear any audible knock whatsoever so here's what I've checked so far:
Now, I swore it was the KS picking up false knock so I replaced it. Before the new knock sensor it was picking up knock all over the place - randomly - and now it's primairly picking up knock at idle and pulling 12 deg at Idle? What else can I check? Could the plugs be bad? Check the resistance of the wires and see if I have a bad one?
Solomon has tuned my car and some guys say that his high timing can cause knock, but I have installed an old tune (before Solomon) and it still picks up knock the same?
I'm pulling my hair out here, any help is much appreciated!!!!
Here's my dilema. I am picking up knock on my PCM (seeing it thru Datamaster) and it's pulling upto 12 deg timing. Now I cannot hear any audible knock whatsoever so here's what I've checked so far:
- Fuel Pump - New Racetronix and putting out the proper pressure
- KS circuit is stable at 5v
- KS is new and tq'd to 14flbs with no thread sealer
- No arching of wires
- Car doesn't seem to miss (however it's hard to tell with this choppy cam)
- Injectors all OHM out properly
- LT4 KM is installed
- No exhaust rattles, or leaks
- No vaccum leaks I can find
- Pulled VC's and the rockers look fine and are not loose
Now, I swore it was the KS picking up false knock so I replaced it. Before the new knock sensor it was picking up knock all over the place - randomly - and now it's primairly picking up knock at idle and pulling 12 deg at Idle? What else can I check? Could the plugs be bad? Check the resistance of the wires and see if I have a bad one?
Solomon has tuned my car and some guys say that his high timing can cause knock, but I have installed an old tune (before Solomon) and it still picks up knock the same?
I'm pulling my hair out here, any help is much appreciated!!!!
Last edited by DAVE00; 06-30-2011 at 06:50 AM.
#2
TECH Senior Member
iTrader: (2)
The PCM will retard timing far before you can hear any audible knock, so that doesn't help in the diagnostic department.
I would run some 100+ octane to determine whether or not the knock is real or false. If it turns out to be false, then have the KS circuit desensitized.
I would run some 100+ octane to determine whether or not the knock is real or false. If it turns out to be false, then have the KS circuit desensitized.
#3
The PCM will retard timing far before you can hear any audible knock, so that doesn't help in the diagnostic department.
I would run some 100+ octane to determine whether or not the knock is real or false. If it turns out to be false, then have the KS circuit desensitized.
I would run some 100+ octane to determine whether or not the knock is real or false. If it turns out to be false, then have the KS circuit desensitized.
#5
TECH Addict
iTrader: (3)
I had knock at idle and when I just touched the gas it would go away, Granted I had a supercharger but it was so close that at idle it was vibrating against the block causing the ks to pick it up, You sure no headder or Y piped is close to the K member or anything like that?
#6
I had knock at idle and when I just touched the gas it would go away, Granted I had a supercharger but it was so close that at idle it was vibrating against the block causing the ks to pick it up, You sure no headder or Y piped is close to the K member or anything like that?
#7
TECH Addict
iTrader: (3)
another thing, does it do it only on cold start ups? does it go away after the engine warms up? Reason being, Forged pistons tend to have some piston slap when cold until they heat up and expand. but I would not worry about that knock, the engine is in a no load condition so it would be very unusual to have true detonation at idle.
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#8
another thing, does it do it only on cold start ups? does it go away after the engine warms up? Reason being, Forged pistons tend to have some piston slap when cold until they heat up and expand. but I would not worry about that knock, the engine is in a no load condition so it would be very unusual to have true detonation at idle.
#10
If not, I'm going to pick up some 100 octane to see if this is truly false knock.
#12
TECH Veteran
iTrader: (12)
I have come to the conclusion that the parts store KS might have been bad. I OHMd it and it was the same as another aftermarket I had in the tool box. I installed the second one and the random KR is far far less. I also did not use teflon tape on the threads but I am not sure if that made a difference. I think I got some questionable gas and it was just bad enough to make a suspect KS freak out.
#13
I have come to the conclusion that the parts store KS might have been bad. I OHMd it and it was the same as another aftermarket I had in the tool box. I installed the second one and the random KR is far far less. I also did not use teflon tape on the threads but I am not sure if that made a difference. I think I got some questionable gas and it was just bad enough to make a suspect KS freak out.
Al