ECUflash How to read knock with evoscan?

[sadc]

I have the evoscan software for my 97 gsx. While im logging, I have tabbed "knock sum" and "Knock voltage". But the only thing I'm getting feed back on is my knock voltage. While my knock sum is reading 0 at all time. Now I know dam well I have 0 knock. So which one am I suppose to look at. Or is my knock sensor bad?

 

[the_mork]

The knock sensor is nothing but a sophisticated microphone and the voltage that you will see in evoscan is only a reading of how much noise the knock sensor is picking up and is essentially meaningless for the daily tuner unless you are also logging the knock threshold. When the knock sensor voltage crosses this knock threshold (loud noises) then you get a knock count and depending on the severity of the voltage that count may be multiplied by a few different values to show the knock count you see on your logger and what the ecu uses to determine how much timing to pull.

The short answer is to just log knock count. I do believe that evoscan may have the request wrong for knock count in 2g DSMs because it is different than evos. Knockgoon knows something about this IIRC and I think it is mentioned in several threads about evoscan logging and ecu flashing.

If you ever want to test catching knock you can force a transitional knock by changing boost pressure significantly in the middle of a pull. This is only realistic with an EBC or ecu based boost control. Running excessive timing can show it too but I would not suggest this due to the potential for engine damage.

Let me know if you need more information. The knock control system is fairly complicated but also pretty cool and extremely effective to the point of being significantly superior to nearly anything from a standalone system.


I found the post about fixing the requestID for evoscan, you can read it for yourself since it is a very good post and worth reading.
http://www.dsmtuners.com/forums/151814357-post106.html

 

[98gsxtuner]

Also if you are using EvoScan to log KnockSum on a 95-97 the RequestId should be 3E not 26.
KnockSums address is different between 95-97 and 98-99.
Address 26 will always read zero on a 95-97.

 

[98gsxtuner]

I just pulled that off of ceddy's mhi scan thread.

 

[sadc]

Nice find. I tried to comprehend the posting. Let me see if I get this right. If I change the setting to 3E instead of 26. I should be getting my knock counts. The knock counts if it passes 1 on the graph, like it did in that guys posting? Sorry, im a nub with this tuning. I've had this software for 3 months and only now im starting to use it

 

[the_mork]

Yes, use 3E, it counts as knock if it shows up at all. 1 count of knock is 1 count of knock. His post was showing how the other request showed a maximum of one knock, it looks more like a knock threshold or a knock count before the multiplier is used.

Just for your reference many tuners will ignore one or two counts of irregular knock, Knock is generally only considered a problem if it is persistent and severe. So if you pull a log and you find one count of knock at around 4000 RPM, don't pull timing there instead run another log and if it is clean then your are fine, if you pull another log and knock is still there then pull a third. If the single count exists in all three logs then I would make my AF ratio .1 richer in that area, but if the knock shows up as a two or a three in either of the two extra pulls regardless of if it doesn't happen in one at all then I would pull one degree of timing.

Phantom knock can also be a problem, and it is fairly easy to see. Phantom knock is generally severe, repeatable, and does not respond to timing adjustments. If you run into this issue then I would suggest putting race gas in your car. If the knock persists then I suggest that you have phantom knock. Fix the physical issues of your car that causes the phantom knock such as lifters, bouncing exhaust, etc then run again on race gas until the knock is gone. Then go back to regular gas and tune out any further issues. If it responds to timing pull or race gas it is real knock.

 

[sadc]

Dang I got no luck with it . I still get 0 counts. I changed the request to 3E, and it still doesn't log it. Is my function suppose to be at "x?" or am I suppose to change it

 

[the_mork]

It should just be x but having 0 counts of knock isn't a bad thing.

 

[sadc]

untuned. And my exhaust is blacked out by the carbon build it. I think im sure I have knock. Guess that means I gotta change my knock sensor

 

[the_mork]

What AF ratios are you seeing? You can't be running your car on 660s with not tune at all, it must have a rough tune at least. How much boost are you running? Generally a low boost rich tune will not knock at all unless it is incredibly and stupidly rich enough to foul things out. There is a condition of "rich knock" but you probably aren't getting it.

In my opinion if you are really concerned then you should create a det can. It is a simple device that amplifies certain noise so that it can be heard in the cabin or recorded to an audio recorder. With a det can you can actually listen for knock and verify if it exists, it is extremely useful for verifying phantom knock or in this case a lack of knock.

I'll see if I can find a link and then I'll edit this post but if not you can find information on google and probably also evolutionm.net


Links:
Creating a det can.
Browser Warning

Det can discussion.
Listening for Det - evolutionm.net

I really think that as a community we should really be exploring the use of det cans more thoroughly. Honestly every local club only needs one or two systems as a way to deal with an all too common problem of phantom knock and variance in engine harmonics of built engines.

 

[sadc]

oh cool thanks, I just have a piggy back system. And on my Hi setting I have it like at -46/-43 the whole way. And it stays pretty good through WOT

 

[saechao04]

Reviving the thread, what requestID should be used for the 99 ecu's?

 

[the_mork]

3E it was mentioned in this thread and linked to. No problem if you missed it but if you want more information on why and a clear demonstration on the difference then follow the link I posted earlier to knockgoon's post.

 

[saechao04]

I only says 3E for 95-97 ecu's, or am I still missing something?

 

[Ceddy]

I only says 3E for 95-97 ecu's, or am I still missing something?

98-99s use 26, like the Evos, no need to change anything.

 

[allrice4g63]

Bring it back from the dead again.. What if 3e or 26 does not work. I am seeing knock voltage, knock change, knock base etc... But i still cant get knock sum to work. I am using the vag 409.1 to log with. Any ideas?