Hey Guys,

How is everyone tuning closed loop knock.

ie in closed loop you have no input into the fueling so the ECU aims for 14.7:1.

if I am getting knock in these areas must I either:
* reduce timing advance
* get out of closed loop (ie change TPS or Load maps)

Cheers
Dave

 

eeeyyyyep. I decrease timing.... however I have found that timing reductions don't help as much in closed loop for some reason. I've had to reduce timing quite a bit in the 90ish load and 2000RPM area. I think that's due to my lifters tapping during cruising though.... which also might be why the timing doesn't help as much... although it does help.

 

Lifters tapping? Do you have aftermarket cams?

 

no, stock motor 25k kilometers on it..

 

right or wrong i have been lowering timing.

a lot of the time it seems to be during transitions, decel /accel on my car. so the issue of closed loop is not there.

So you are getting knock just cruising? Same spot all the time?


heck, Ive pretty much gutted into the 70 column.

 

Yes, I have aftermarket cams so yes that's probably why I have lifter knock, that is if I do have it. I'll probably get around to fixing that eventually. Yeah, timing seems to be the only way to fix it for the lay-tuner. If someone could totally decipher the knock tables perhaps we could desensitize the ecu that small window during cruising

 

One possibility, when EGR valve opens in closed loop part throttle, even though it's rich in CO2 as an antidetonant, the temps are high enough to cause an initial mild knock that is picked up by ECU.

I wouldn't worry about it if it's mild, if it's what your encountering in the first place.

 

hmm i have a simlar issue. always happens (or starts) at load 70 and generally 27-2800rpm. but i have tired lowering timing and problem still there. its an issue if the knock starts at the pull i have to abort otherwise it keeps knocking through the rev range. it also happens at cruise.

 

Good thought. We'll see b/c I've now disabled my EGR check and put on a block off plate. I'll letcha guys know what I find... as soon as I get fenders so I can get er back on the road.

 

Another possibility is just plain engine harmonics while background noise is at a minimum - low load. Iv'e tried racegas and retarded timing and no help.

 

I have this issue on my Evo 5,
at 70 to 90 load around the 3k to 4k I am getting some pretty severe knock at times,
tried to tune it out and it seems to have solved the issue as my car dont have EGR so I ruled that out,
but I need to log some more to be sure its gone

 

I get that low rpm knock every now and then too. It's only like 1-2 counts though, but its around 2500rpm, 70-100 load.

 

There's a close loop timing modifier .. you need to modify that

Though I don't know if it's available in versions other than JDM / EUDM

 

Might be a combination of your Mivec map and your Timing Map - maybe see which one is easier to compromise on...

I suspect ambient temps and reduced air density might be making things worse - hows the weather down there?

Sal
.

 

Would this be like vacuum advance?