I need some direction. I have run a datalog and I see that the knock counts go up as I drive around. Is this right. Does adjusting timing correct this. Maybe I could send someone my datalog so they can see what I mean. I am about to start getting my blms in order, but this knock count thing has me a bit concerned. Please advise. Thanks

 

If they're "true" knocks, then the timing is either too much in the areas where you're getting the knocks, or it's too lean in those same areas, or a combination of both.

However, they can also be "false" knock counts. If they're reading them all the time, then it's most likely some other noise the knock sensor is picking up. Any chance you have an exhaust/header leak? Or timing direct drive type gears instead of a timing chain?

 

My buddy is a mechanic and he is telling me that if it was indeed knock I would know for sure. I am running headers, but I don't think there is a leak.

Sounds like it should be alright to start modifying my tables to get a 128 BLM across the board (right?). I just wanted to be sure that these "knock counts" wasn't something I needed to address before continuing on...

 

I wouldn't assume that, myself.

I'd try to run it down and get them eliminated so that you can tune for sure and see when actual knock occurs. The engine can knock without you being able to hear it. When you actually hear it chances are damage is or already has occurred. Are you using a knock sensor from a 350?

 

yes, I changed the sensor about a year ago. I think it is working since I am getting counts.

So you are saying I should look at the existing timing and maybe turn it back a bit to see if the knocks go away...

 

That would be a good start - take some timing out at idle and make sure you're not knocking there first.

What was changed on the car when the knocks started? Are you sure it's a 350 knock sensor (diff than 305 I believe). Also, what prom/BIN are you using?

 

Thanks for taking time on this problem....

I originally had a 305 but modified to a 355 and yes I changed the sensor to a 350 knock sensor. The problem never really started it has probably always been there. The engine swap only has about 5000 km on it. I am running the stock ARAP bin. I have bumped the inj constant to 21 to get things running well with my setup (please see my sig - at top). The only reason I noticed the knock counts was when I ran my first datalog. I am heading over to my buddy's shop to make sure there is no knock at idle.

I am still a little confused on how I am going to control the knock while driving. Is that all controlled by retarding the timing?? I thought the MAF tables would take care of that. Like you previously posted maybe these knock counts are not true knock and are vibrations or something???

 

It probably is true knock since the ARAP bin has way too much advance (IMHO). You need to make sure your base timing (with single distributor wire disconnected) matches the value in the program - 6 degrees is what is commonly used. Then start pulling out advance from the spark table where you see it in your data logs. Typically, you will pick up knock retard when you start loading the engine. The spark table lists the advance value for various values of rpm and load value (LV8). Look in your datalogs and note the range of rpm and load value where the knock is occuring - then find that range in the spark table and reduce those advance values by one or two degrees, load the new table into the ECM and drive it again. Eventually, you will get it running without knock.
This is the method that I used with a 165/6E. Worked for me
Of course, the usual disclaimers apply - IOW, you break it, you fix it!

 

Thanks for the point in the right direction. It is really helpful when the actual tables to look at are mentioned. I am very green at this tuning thing, and I hate it when I break things that could have been avoided. If you have any other helpful advice to send me down the right path I would really appreciate it.