Knock Question

[98WhiteDevil]

Mods are in sig. When at WOT I see knock from 3000-6700, the knock ranges from 2.5-4. I have my VE and PE perfect so I know that's not the issue. My A/F is around 12.7 at WOT. I have a 98 and was told I shouldn't have to do anything with timing so I haven't messed with timing yet. Could it be that I just need to desensitize my knock sensors. If so what table do I do this in and what should I change the values to.

Car Craft Summer Nationals is tomorrow and I'm hoping to get this problem fixed by then so I can get on the dyno. Any input would be much appreciated. Thanks

[98SS2836]

are you using the new gas?

[dfe1]

My A/F is around 12.7 at WOT. I have a 98 and was told I shouldn't have to do anything with timing so I haven't messed with timing yet.


Who told you not to mess with timing? Were they coherent at the time? One thing is for certain, your engine doesn't know about the conversation, and if you're seeing knock over that wide an rpm range, it's probably real. Your engine doesn't know or care what should be-- it only knows what it likes and if it's knocking, it doesn't like someting. If you A/F is 12.7:1 at WOT, the only other probable causes of the knock are timing and or excessively high inlet air and/or coolant temperature. Drop the spark back a couple of degrees and see what happens. Also take a look at temps and make sure they aren't too high.

[98WhiteDevil]

Temps are fine, I did have some problems with the temp sensor but I recently fixed that. The problem is, when I log the KR or Spark Advance maps, it only logs in the first column. I don't know why it won't log across the maps, so this could be a long and tedious process of tracking down which cells to change the timing in. I log these on my dad's 02 SS with the same setup and it logs across the maps, but mine only logs in one column. Anyone else run into this on a 98?????

[dc_justin]

As posted on LS1tech:

Changing heads/cam almost certainly will affect your dynamic compression ratio and likely the burn characteristics inside the combustion chamber. You're likely going to need to pull some timing out to get rid of that knock or richen it up a lot, which will probably lose power.

Don't be afraid of pulling back the timing. It is not a "more is better" type of a thing. Peak power is typically made a few degrees before knock starts to set in.

As for your dad's situation, the stock 98 Spark tables are considerably more advanced than that stock 02 Spark tables. He is running with no knock because his tune wasn't close to it's peak performance point from the factory, whereas yours was...

Make sense?

[dc_justin]

Temps are fine, I did have some problems with the temp sensor but I recently fixed that. The problem is, when I log the KR or Spark Advance maps, it only logs in the first column. I don't know why it won't log across the maps, so this could be a long and tedious process of tracking down which cells to change the timing in. I log these on my dad's 02 SS with the same setup and it logs across the maps, but mine only logs in one column. Anyone else run into this on a 98?????

That would be a problem with either the PIDs you are using or how they are set up in the map. Hit Ctrl+Enter on the map that you are looking at, select the Column tab and make sure that the PID you select is similar to "Air Mass Per Cylinder (Grams/cyl)".

[dfe1]

I just tuned and data logged a 98 Camaro this past weekend and logging worked fine. I assume you have the latest version of EFILive????? If you can't resolve the issue, PM me a log file.

[98SS2836]

I have a 98 and log everything fine.

[98SS2836]

My car hates the stock 98 timing table im running a z06 + three and it hates that too.

[98WhiteDevil]

I just tuned and data logged a 98 Camaro this past weekend and logging worked fine. I assume you have the latest version of EFILive????? If you can't resolve the issue, PM me a log file.

Here's a recent log. You can see what I'm talking about in the KR (map E) and Spark Advance (map D) Maps. Let me know what you come up with. Thanks

[The Alchemist]

having done work with the knock calibration and using a headphone set I can safely say that if the ECU detects knock and you see it as knock retard on your scan tool then chances are its knock!!! Funny that.
You'll never hear the sutble knock during a dyno run or a skid down that local back roads that the factory system will "hear".
Retard your full load timing by 3 to 4 degrees and repeat yout tests until there is no knock retard showing > your engine will love you for it :)

[johnv]

If you have a line through CYLAIR Grams/cyl on your MAP you have selected the wrong PIDS to scan to support that MAP that is why all logged info is in 1 columb.:wave:

[98WhiteDevil]

There isn't a line through the CYLAIR name. It works when I scan my dad's car, but not mine. I'm using the same PIDS for both cars, that's why this doesn't make sense to me.

[johnv]

maybe you need to validate the pids for your car ?:nixweiss:

Are you tuneing Mafless ? if so you will need to make a new map and use DYNCYLAIR (predicted grams of air per cyl) instead of CYLAIR (air mass per cylinder) as the later requires the MAF to calc values.

[98WhiteDevil]

maybe you need to validate the pids for your car ?:nixweiss:

Are you tuneing Mafless ? if so you will need to make a new map and use DYNCYLAIR (predicted grams of air per cyl) instead of CYLAIR (air mass per cylinder) as the later requires the MAF to calc values.

I did all this already. My dad has the exact same setup as far as mods go but he has an 02. Logging works perfect for him, but only logs in one column for my car. So I'm not sure how there could be anything incorrect with the PIDS or logger considering we have the same setup and it logs perfect on his car.

Thanks for the reply's, keep them coming, I'm sure there's somebody that's had this problem.

[joecar]

I did all this already. My dad has the exact same setup as far as mods go but he has an 02. Logging works perfect for him, but only logs in one column for my car. So I'm not sure how there could be anything incorrect with the PIDS or logger considering we have the same setup and it logs perfect on his car.

Thanks for the reply's, keep them coming, I'm sure there's somebody that's had this problem.Goto your spark table in your tune, and look at the link pids on each axis of the 3D view;
make sure the scan tool has these exact same pids selected.