Battling the knock

[Gtpdz]

So the good old knock problem, just got my Link V3 in, seeing 15 degree of knock around light throttle cruising, mostly notable when turbo spools up during up hills or start from a stop, about 0.7-0.9 load factor. Lift throttle off and push it again sometimes will take the knock away. No knock or less than 5 degree knock when making a pull with wide open throttle when turbo is spooled up.

Phantom knock? Or it's real knock? /ubbthreads/images/graemlins/confused.gif

 

[GSTwithPSI]

Post a log.

 

[Gtpdz]

Here it's the log:

Click For Log 1

Here it's a similar log after the last one, just pulled 10 degree of timing across 2000-4000:

Click For Log 2

 

[GSTwithPSI]

I only looked at log 2.

For starters your open loop thresholds are all dicked up. They are WAYYYY too high, and static across the board. Your log is showing 50% TPS in some cases while the car is still in closed loop. As a result, the car is probably knocking. Go fix that, and I bet the knock goes away for the most part.

Your OpenLoopMaxOct is too rich. 9.3 is pig rich, and should be leaned out substantially

Your TmngMaxOct is way too hot. You'll probably be lucky to get 17-18* peak timing on pump gas. You're at 24*.

I could make some other recommendations, but I need a full mod list. Specifically, what injectors, and what's your base fuel pressure. Also, I don't see a WBO2 assigned. Is that correct? Also, how old is your knock sensor?

 

[Gtpdz]

ok changed my open loop setting today and fixed some injector numbers in global fuel setting.

I'm running PTE 550cc, AEM wideband with gauge, not hooked up to ecu yet, stock fuel pump rewired and stock fuel regulator.

And this is today's log: Click

I noticed that most of the knock happens during close loop with moderate load when the turbo is spooling. I check the wide band during WOT open loop condition and it matches up with my fuel table, around 10.4-10.2

 

[GSTwithPSI]

Ok, your thresholds look good now.

From my calculation, your global fuel should be around -18% assuming a 37psi base fuel pressure. You're quite a bit off that mark. Is there a reason for that? Deadtime looks good based on ECMtuning's config page.

Your fuel table is still far too rich, at 9.3:1 (open loop portion).

Your timing table is still too hot as well (again, open loop portion). Regarding your phantom knock, it looks like you're getting a lot of your knock between 1500 and 2500 RPM, and .3 and .8 load factor. You could try and pull a few degrees out of the table there, just to see how the car responds.

You're pulling quite a bit of fuel with your MAF comp, which I would assume is because you have your global fuel setting far too rich. You need to get that WBO2 hooked up to dial in your MAF. A properly adjusted MAF is the cornerstone of a good tune.

Also, you never said how old your knock sensor is. Have you checked to see if it has pissed out all the black goo?

To be honest, you'll get much more help over on DSMtuners regarding tuning advice. I'd move this thread over there once you get your WBO2 hooked up and functioning.

 

[Gtpdz]

Thanks a lot for the feedback /ubbthreads/images/graemlins/tongue.gif

Knock sensor is brand new, hand tight into the block,

The global fuel adjustment was because I couldn't get the idle combine fuel trim into +/- 4% unless I raise the global fuel or dead time.before that when I was set at -18% and 180 dead time I got it around 14-16% combFT.

As for the timing I tried dropping 8 degrees across the board. Still gets same count of knock around that rpm range.

I will try look into the wide and set up and make a thread on DSMtuners.

 

[transparentdsm]

there is more Brett, he needs to change his injectors calculations. you car is apparently running 474's and nothing has been changed in the timing or open loop tables. everything is stock. Also the area where your seeing phantom knock is very low under almost no load. first thing change the knock cell to 1 or 2 at the most, 5 is only ok in 2G DSM's and i don't even agree with that, then go to the ALS/knck tab and and raise the RPMS in the knock section to 3000-3200.

put a open ended wrench on the knock sensor and give it a little tighten. hand tight is to loose.

 

[GSTwithPSI]

Hey Shane,

I think I've addressed most of the points you mentioned. Just so we're on the same page:

Global fuel, base fuel pressure, and deadtime all account for the injector calculations you're referring to.

In addition, the stock 1G maps (fuel and timing) aren't great for a modified car. For most setups, the stock fuel table is too rich, and the stock timing table is too hot. This is why I suggested to lean out the fuel table and pull the peak timing numbers down. Those two suggestions really only apply at WOT for the most part, and I threw them out as more of an FYI since they don't directly relate to the OPs initial question about phantom knock.

I did forget to mention the ability to adjust the knock threshold, but that's typically user preference. As long as you know what you're getting yourself into, adjust it a high as you'd like.

Agree on a hand tight knock sensor being too loose...I wonder if it's even there anymore?

 

[Gtpdz]

Finally checking the fuel pressure today... surprise, it's 43 psi when the pump is on with engine off, looks like it has an auto FPR on the rail...

Also got the injector cleaned and flow tested, they are rated at an average 546 cc

 

[Gtpdz]

Make another run today, fixed an injector o ring leak and loosen up the knock sensor a bit,burp the coolant and seafoam the car for the first time since I got it... looks like knock issue has been greatly improved, don't really see full knock happen as much as before, knock sensor is set at 2500/10%.

Will try seafoam it again sometime soon and see if it improve it more.

Click for Log

 

[GSTwithPSI]

The permissions for the log file on your Google drive are private, so I can't view the log.

 

[Gtpdz]

Permission fixed