Tip-out knock

[welaish]

Hello All, long time did not post anything. my car was running great on HolyCrapItsFast Tune.

I have put 1000cc injectors and made the proper adjustment and it drives amazing. but I have tip-out knock on very slight throttle, when I left off but still slightly on throttle I can feel the car hesitate a little bit.

what should be done:

1. Reduce/Increase Tip-in?
2. increase Overrun?
3. I feel the car is trying to switch to openloop on lift of but its not happening because I am applying slight throttle, so how can it be tuned to be on closed loop for longer period?
4. reduce timing on this area?

Log: https://1drv.ms/u/s!AhnqO46jwFi7gaI4MEPy8guuk0aVvg

 

[welaish]

The Graphs on DataZap, http://www.datazap.me/u/welaish/tip?log=0&data=2-5-7-8

 

[goldfingerfif]

I don't see where you even logged feedback knock, you only logged knock count which isn't actual knock just that the knock sensor picked up a noise and it associated it with cylinder 4. It could be the ping of the butterfly valve closing against the throttle body or as you let off the gas something moves in the engine bay and it detects it. Because of the location of the knock sensor that is the reason it is biased towards cylinder 4 from what I remember.

I was always told if you look at knock sum thinking there is an issue you will only drive your self to insanity as you will never be able to eliminate it. Mine goes up every time the AC compressor kicks on, I've gotten my count much higher than yours sitting in a drive thru.

It is only meant to be looked at if there is an issue, so say you had a bunch of feedback knock it can likely help determine which cylinder(s) it is concurring on. Or if car isn't running right and historically cylinder 4 is always high and now you check and cylinder 2 is at 300 and cylinder 4 is at 40 and cylinder 1 and cylinder 2 are around 3 sum count...well you might want to look into cylinder 2 having an issue.

In your log I see many instances where the you let off the throttle and knock count didn't go up because it is meaningless without Feedback knock to know if an actual knock even occurred.

If there is any problem you have a huge -25% fuel being pulled on AF Correction but you didn't log AF learn.

I could be way off or completely wrong so I'll let someone else also chime in as I still have a tough time reading logs without some other vital fields such as RPM, Feedback Knock, Fine Knock Learn, A/F Learn (LTFT)

 

[welaish]

Thanks for your reply, I appreciate it.

Knock Sum is the main source of knock, Feedback Knock will pull time only if the load is within the defined threshold on the ROM table, my car never pull time without increment on the knock Sum count.
on my car it works like that:
IF knock count increases and load is bigger than 1.0 g/rev
THEN Pull -1.4
Else Ignore

I agree There is a lot of engine noise during cruise and the knock sensor just increase the count. but my situation is the knock sum increases a lot on very light throttle and on/off the throttle.

I am logging cylinder#4 because it picks a lot of knock, that is why I am logging it and as explained the ignition timing will not get pulled with the load below 1.0 g/rev.

Also my A/F learning is within the 3% idle and cruise. the A/F correction goes to -25% during shifts sometimes +25%. but it is within the 5% during Idle and Cruise.

 

[HolyCrapItsFast]

Hello Wael!

Looking at the log your over-run enrichment is okay. Tip in can use a little work though. Can you give us another log showing also feedback knock and fine learned knock just so we have the whole picture?

To stay in closed loop longer you needs to adjust the closed to open loop delay but I have never had to do this. The stock values have always worked for me and it would suggest a tuning issue to me. You are entitled to as many adjustments to your tune as you want and if you would like we can explore the issues together.

 

[welaish]

Wow that's amazing, but I had to change a lot of things after the injectors and fuel rails install. To be fair I can contribute by half of the tuning fees. What do you think?

 

[HolyCrapItsFast]

I require no fee. You are a lifetime member so freeeeeeeeeeeeeee! :lol:

Okay so do you remember how to use that tuning database website? Do you need me to send you the link?

I will need to start with what you have on the car currently and I won't touch anything that you don't want me to adjust. Lets work on the knock you are seeing and then address anything else you observe.

Just out of curiosity, did you see any tip-out knock like this before the injectors went in?

 

[welaish]

I require no fee. You are a lifetime member so freeeeeeeeeeeeeee!

Okay so do you remember how to use that tuning database website? Do you need me to send you the link?

I will need to start with what you have on the car currently and I won't touch anything that you don't want me to adjust. Lets work on the knock you are seeing and then address anything else you observe.

Just out of curiosity, did you see any tip-out knock like this before the injectors went in?

Yes please send me the link. I will send you updated list of mods.

No I didn't have that before the injectors.

 

[HolyCrapItsFast]

http://www.netzonexpress.com/TuningInterface/default.asp

 

[welaish]

Sent