Knock when letting off???

[billsgn]

I know this sounds weird, but I am getting up to 40 degrees of KR when letting off. I recently installed a SMC Alky system and was out testing it with my TurboLink hooked up. I was running 20lbs of boost and was getting zero knock all the way to 95mph. As soon as I let off the throttle, my TL recorded 14 degree's of KR. Second pass, it recorded 26 deg's of KR's, and the third and last pass I got over 40 deg's of KR. All of this only after the TPS was at 1 volt of less, meaning after I let off. Obviously I didn't want to try it again. Does anyone have any idea what is going on here? Could the flutter be causing this or is there something else wrong? I plan on changing my timing chain and gear in the morning because I think they are the original ones (car has 120,000 miles on it). Could a stretch timing chain be the culprit? Any suggestions or help would be greatly appreciated....TIA

 

[boostedmaxPSI]

Billsgn

I just did a search and found a guy on the board with a hotair car that had this problem and it turned out to be his ECM.

And then another had a bad ground!

Are you hearing any detonation or just seeing it on your scan tool?

Frank

 

[billsgn]

Frank, it's all your fault!!!

j/k.....

The only thing I hear is the flutter when I let off. Only showing up on my TurboLink.

 

[boostedmaxPSI]

read this

http://www.turbobuick.com/forums/showthread.php?s=&threadid=58663&highlight=false+detonation

Read the part about the TurboLink and Cam sensor.

 

[turbo buicks]

i would look at the chain and for false knock and bad motormount. a stock timing chain is probably in pieces by now seeing as how its made of nylon. get it replaced. i would imagine 40 degrees of knock would grenade a motor instantly.

 

[billsgn]

Interesting......

however, I have not changed anything on the car except for installing the Alky kit. Cam sensor couldn't have moved, and I am not seeing anything in the oil or coolant. I wonder if my TurboLink is not working properly....I had problems getting it to work at all when I first got it. I will call Ken Mosher tomorrow and see if he can tell me whats going on by looking at the TL file. I still plan on doing the timing chain and gear tomorrow. Even if it's not the problem, it definately is due for a replacement.

BTW, Dan was out driving his car yesterday and didn't stop by like he said he would. I think we need to get him the "for sale" sign!!!

 

[billsgn]

I was thinking the same thing....

Originally posted by turbo buicks
i would look at the chain and for false knock and bad motormount. a stock timing chain is probably in pieces by now seeing as how its made of nylon. get it replaced. i would imagine 40 degrees of knock would grenade a motor instantly.

I'm glad it is happening after I let off, otherwise you would be right about the engine grenading. I am doing everything I can to keep this engine together until this summer. I plan on doing a complete rebuild then, but I still feel the need for speed!

 

[boostedmaxPSI]

BTW, Dan was out driving his car yesterday and didn't stop by like he said he would. I think we need to get him the "for sale" sign!!!

Ya! he came by to show me his new DP. Way to go Dan... I guess well have to hold off the "For Sale" sign for now. But I'm watching..........

 

[REDS HOT AIR]

my d/p hits the bottom of the ac box when I let off

nothing im going to worry about

get someone to stall it up in revese and see if it hits