Well, even though this IS jcsbanks thread, I would appreciate a good explanation of the "shift knock" thing and the fix. All in the interest the community etc etc.

 

............

 

Rapid transitions in timing can encourage knock. Also, there are possibly some control issues related to airflow and its measurement at a given point in timing during transitions. The MAF sensor tends to get advance warning, and some will read an inlet manifold filling spike on an acceleration transient. The throttle can close and the timing advance before the manifold has reached its final vacuum point. So you can have a combustion event or two which will probably be a bit lean and advanced - the ignition still operates on lift off.

Retarding the timing in the 140-220 load range seems to fix it - since we don't (yet) have a maximum ramp up rate of timing that is programmable.

 

Thank you for that.
I thought it may have been something to do with the decel ignition retard parameter.
That would explain why Autronic have a ramp-rate variable I guess.
Another good patch for tephra?

 

Anyone confirmed the source of high knock sums during stationary rev limit fuel cut? Wondering if it's just piston slap

 

I find if you just hit the gas pedal hard, from idle, to build boost, you get high knock sums.

But if you gently build up the revs till you hit the stationary rev limit, and then go to the floor with the pedal to build boost, you don't get the knock sums then

 

I keep getting a nagging 2500rpm knock of about 2-3 counts. Is it pretty save to up the load threshold there to 120, and then up the knock multiplier to 20? What conditions would cause real knock at 2500rpm other than rapid timing changes? Does rapid timing changes cause real knock?

 

I wouldn't be so quick to call that false knock, 2-3 counts is not typical of false knock characteristics, make sure its your tune. throw in some 100 oct and see if the knock goes away

 

John, can I get some help with 98640014.
I have found the LOAD THRESHOLD V TEMP
and OCTANE UPDATE.
Just need the three multipliers and the adders.

 

The addresses from post #24 (Page 2) are the same in 98640014 as they are in my 80700010 rom, so that should get you started. I am pretty sure I have the adder and multiplier addresses as well.

 

Thanks Matt, I must have missed something somewhere.
I had tried those addresses, but needed to change from uint8 to uint16 to get it to work properly. Did not spot it until I did a hex examination.
Thr three multipliers and the two adders give the usual values that people are finding.

 

Thank you. Have had low load/low rpm/ low knock counts in the 2500-3000 range that could not be addressed with timing retard or octane changes.

Coming across this thread has helped me resolve my low-load part throttle knock. Upped the knock load to 80 at 2500 and 3000 and raised low rpm knock muliplier to 16 and the problems are gone. Kudos to all contributors-this is a great community.

 

I did this for the 88590015 and the tables on here i found for the 94170014 rom on my desktop here and it worked. I did the same thing on my laptop and its not showing up on the ECUFlash... What could I be doing wrong??

 

I am going to look at a small issue with my engine soon.

I noticed that during warm up when the coolant is about 60-70C and when I am 2500 RPM on part throttle with 60-80 load that I can get some quite impressive knock counts (sometimes a 4, after SD conversion a 13 on one occasion - perhaps I was hitting slightly different load sites). It isn't easily reproducible, I don't hear any detonation in the cabin (I used to be able to hear lift off knock before I mapped it out), and I run stock FQ360 timing in this area of the map on higher octane fuel than it is mapped for. I can't get it to do it when warmed up.

This raises a few issues:

1. Since knock control load drops at 2500 RPM I wonder if I dropped this area to 2000 RPM whether I would get a load more knock sums.
2. It might be a good idea to drop it since I could be having real knock during spool at 2000-2500 RPM (which was about 500 RPM higher before I tuned the boost and improved the exhaust).
3. Is this real or false knock (need to get the det cans out and get my friend to drive, but may be difficult to trigger it!) I did think it went away with dropping timing, but I need to test a lot to be sure as it is sporadic. I suppose I could always use some methanol.
4. Need to categorise the warm up ignition compensations better. This could easily mutate into a more complete disassembly of the timing routines like I did with MAF to IPW paths.

Comments/experience/advice/questions?

 

The more control we can get over the knock routine the better isn't it ?

I mean if we are getting random phantom knock, and there is a way of dialing it out, then it can only be a good thing.

Obviously if it is real knock, then thats a little bit different.

Have to say though, that with the SD patch, most of my random knock around 60 - 120 load, did pretty much vanish.