Fun with false knock

[ledzeppac]

I "believe" I have a false knock issue.

I get around 10 degrees of retard at shifts and then it lightens but will still fluctuate around 2-4 in gears. I beleive its false becuase everything checks out ok.. I was under the car changing the cat and noticed that my stock downpipe is very very close to the crossover and frame. So close I can actually move it with very little effort and it will rub both. What have people done to get rid of their false knock? Do I have to just deal with it? The car is soooo slow with 10 degrees being pulled out.

 

[Gary Wells]

I "believe" I have a false knock issue.
I get around 10 degrees of retard at shifts and then it lightens but will still fluctuate around 2-4 in gears. I beleive its false becuase everything checks out ok.. I was under the car changing the cat and noticed that my stock downpipe is very very close to the crossover and frame. So close I can actually move it with very little effort and it will rub both. What have people done to get rid of their false knock? Do I have to just deal with it? The car is soooo slow with 10 degrees being pulled out.

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I got tired of worrying about mine and went to 100 octane V.P. unleaded race, and any indication of any knock, false or otherwise, went totally away. I know that race gas is not in your budget, but it seems to me that if you drained your tank and refilled with about 6 gals of 100 octane unleaded, it would help you at least determine whether it is real or false knock. If it goes away or lessens considerably, it was real knock, and if it doesn't change considerable, it is false knock. Just a thought, Phil. What did Lou say about it?

 

[ledzeppac]

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I got tired of worrying about mine and went to 100 octane V.P. unleaded race, and any indication of any knock, false or otherwise, went totally away. I know that race gas is not in your budget, but it seems to me that if you drained your tank and refilled with about 6 gals of 100 octane unleaded, it would help you at least determine whether it is real or false knock. If it goes away or lessens considerably, it was real knock, and if it doesn't change considerable, it is false knock. Just a thought, Phil. What did Lou say about it?

Lou said its normal to get it at shifts.... which I do know that... but 10 degrees at a shift is alot and I still have 2-4 in gear... which I still believe it false...

 

[Gary Wells]

Where you think that the downpipe is hitting, I would grind away a small amount of metal on that bar running down there, just to see if that helps. 10° is pretty scary to me.

 

[ledzeppac]

Where you think that the downpipe is hitting, I would grind away a small amount of metal on that bar running down there, just to see if that helps. 10° is pretty scary to me.

No I'm not gonna grind any metal come on Gary!


Actually I've been living with 10 + for two over two years now...

 

[Gary Wells]

No I'm not gonna grind any metal come on Gary!
Actually I've been living with 10 + for two over two years now...

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You're right. What was I thinking? If that thing lives for 2 years with 10°, it will live forever with it. Don't know what I was thinking. If there was something wrong, Lou would have said something about it. Are you going to dyno it?

 

[ledzeppac]

Probably not... no one wants to see my 175 horsepower...

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You're right. What was I thinking? If that thing lives for 2 years with 10°, it will live forever with it. Don't know what I was thinking. If there was something wrong, Lou would have said something about it. Are you going to dyno it?

 

[Gary Wells]

Shouldn't that thing be doing about 300 at the rear wheel?

 

[ledzeppac]

Shouldn't that thing be doing about 300 at the rear wheel?

Well at 14lbs of boost, 18 degree chip with 10+ degrees being pulled out its pretty slow...

 

[Squid4life]

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I got tired of worrying about mine and went to 100 octane V.P. unleaded race, and any indication of any knock, false or otherwise, went totally away. I know that race gas is not in your budget, but it seems to me that if you drained your tank and refilled with about 6 gals of 100 octane unleaded, it would help you at least determine whether it is real or false knock. If it goes away or lessens considerably, it was real knock, and if it doesn't change considerable, it is false knock. Just a thought, Phil. What did Lou say about it?

Sorry to jump in, but what if you think you have false knock, drain the tank, put in 114 and it gets worse???

 

[ledzeppac]

I "believe" I have a false knock issue.

I get around 10 degrees of retard at shifts and then it lightens but will still fluctuate around 2-4 in gears. I beleive its false becuase everything checks out ok.. I was under the car changing the cat and noticed that my stock downpipe is very very close to the crossover and frame. So close I can actually move it with very little effort and it will rub both. What have people done to get rid of their false knock? Do I have to just deal with it? The car is soooo slow with 10 degrees being pulled out.

Anyone anyone.....

 

[Pronto]

Well at 14lbs of boost, 18 degree chip with 10+ degrees
Run the tank down and try 100 ul. With the same 14lbs and 18 degree and see if you still have knock. If you do it's highly unlikely its false.

 

[John Larkin]

You got a friend close by you could swap some parts with? If so try a few swaps:

ESC module
ECM
MAF

Swap all 3 and see if it goes away. If so, then swap back one piece at a time until knock returns. I think there are only 6 combos possible so it wouldn't take that long.

Lastly try to see if it's external. Remove the serp belt and go for a short burst, maybe 300 yards. You won't have a waterpump, power steering or alternator so it'll have to be real quick on a cold engine/good battery. If there is KR in park, you can remove the tq converter bolts and push it back away from the flywheel. Look at the inside of the shield for scraping also. Rev the engine and watch for knock.

All those are freebies.

 

[mikec1969]

I just removed my engine hold down strap and removed 6 kr on my scanmaster. Any time the car spun the tires it would show kr. Never liked the way it looked anyway. If you really had 10 kr, you woud hear it inside the car. When I first got my car the crossover pipe was hitting the passenger side control arm. Be sure that's not touching.

 

[ledzeppac]

ok guys... I guess no one likes to answer the question....



How do I get rid of false knock? How do I stop the downpipe from rubbing? Can it be stopped? or do I jsut have to deal with it?

 

[Evans Ward]

Have heard that sometimes worn passenger side motor mount can cause DP to sit closer to framerails, etc with a chance to hit possibly causing false knock. Have you checked torque values on your knock sensor? 14 ft lbs is max- anything more and it picks up more engine vibrations. False knock scares me too as it might not be false knock. I installed one of Casper's audible knock detectors as another precautionary since the 1.5 second stream data delay from the scanmaster concerned me. Good luck on a resolution here. Oh yeah- one thing/ mod at a time to troubleshoot. These types of problems always can try one's nerves!

 

[ledzeppac]

Have heard that sometimes worn passenger side motor mount can cause DP to sit closer to framerails, etc with a chance to hit possibly causing false knock. Have you checked torque values on your knock sensor? 14 ft lbs is max- anything more and it picks up more engine vibrations. False knock scares me too as it might not be false knock. I installed one of Casper's audible knock detectors as another precautionary since the 1.5 second stream data delay from the scanmaster concerned me. Good luck on a resolution here. Oh yeah- one thing/ mod at a time to troubleshoot. These types of problems always can try one's nerves!

hmm might be onto something with the passenger side mount...

The drivers is new and good along with a torque strap, no its not th etorque strap thats causing knock...

Knock sensor is 12lbs and yes its good too.

 

[Pronto]

no its not th etorque strap thats causing knock...
Did you try removing it to see?

 

[ledzeppac]

no its not th etorque strap thats causing knock...
Did you try removing it to see?

It knock before and after...

So what has everyone done to stop their downpipe from clanking?

 

[mikec1969]

My guess is the crossover pipe is hitting the passenger side lower control arm. You can loosen the bolts at the exhauast manifold and shift the pipe over towards the driver's side. This is especially true if you have an after market two piece CP. Once you start eliminating sources of false knock, you will see that the torque strap is definitely the cause of some of your false knock problem.