Getting knock at high gears, log attatched

[mnetwork]

The car seemed good recently and then the other day I started getting knock very randomly. Last night I tried tuning the car for 22-23 psi and I would do a few 3rd gear pulls, but then a 4th gear pull would yield a lot of knock, over 3 degrees if I held it. Today I went back out. Turned boost down to 20-21 psi. With boost lower afrs were more rich. Around 10.5 or 10.6 maybe hitting 11.0 for a second. I did some 3rd gear pulls and then I'm cruising in 5th gear and I start pulling, afrs are holding at around 10.6 and then bam I get 2 degrees of knock and let off. It seems that right when the wideband goes lean (11.6) I get 2.8 degrees. Afrs seems consistent at 3rd gear, but higher gears they start to act weird. The logged AEMr1 value and the actual gauge are only about .1 off from eachother.

 

[98gsxtuner]

Just FYI you're log isn't opening.

 

[mnetwork]

I just redownloaded it, it opens fine here.

 

[98gsxtuner]

It asks me if i wan't to find a program online to open it with and when i try it's an error message.

 

[98gsxtuner]

Just figured I would let you know just incase anyone else has this problem.

 

[mnetwork]

Just figured I would let you know just incase anyone else has this problem.

That just means you don't have the file association setup for dsmlink. Just go in dsmlink and open the file from there...

 

[JayRolla]

Well have you checked your knock sensor to see if its leaking and if so it needs replaced. If you wbo2 matches dsmlink you are running real rich. Lean out a little say 10.5 as most the run shows 10.1.

I would turn boost down to about 18psi and see if that gets rid of knock. If so then you know its real knock. I think something else is up. You should beable to run that boost with the 10-11* timing your motor is running.

 

[mnetwork]

My knock sensor was never leaking. I have been fighting knock forever, this car is so hard to tune.

 

[cbrfrenzie]

All cars act differently when it comes to knock, I've played that game several times. When your afr hits 11.6 under boost that can cause knocking if your cylinders are not clean, meaning carbon deposits act as "hot spots". On a friends 1G Talon we could not go any leaner then 11.2:1, otherwise knock would start to show up. On other cars I've been able to go to 11.5:1 without knock. As long as your timing is conservative, get your fuel dialed between 10.5:1 and 11.0:1 under boost, then go from there.

Also make sure the knock sensor is physically tight where it screws to the block, if it is even a little loose it can cause the infamous "phantom knock".

 

[mnetwork]

I doubt this is not real knock as it is only happening under pulls. I'm just trying to see if maybe the car is going lean randomly. Knock is so hard to control on this car. There were even times I pulled a a lot of timing -3 to -4 at spots and I still got a lot of knock. And boost was never more than 23 psi.

 

[olmytsi]

My old motor with bad compression was like that...Could only run 14 degrees of timing and 22 psi max. Now I run 19 degrees and as much as 24 psi on pump with no knock

Not sure what to tell you but is there alot of carbon deposits on the pistons? That will cause knock. Run some MMC or seafoam through it.

 

[mnetwork]

When I did the headgasket last spring there was absolutely no carbon buildup or any buildup on the pistons. They looked brand new.

 

[habitatguy187]

When I did the headgasket last spring there was absolutely no carbon buildup or any buildup on the pistons. They looked brand new.

That was a year ago, who knows what's built up since then? I seafoam my car at least once every 6 months, and it smokes like a chimney each time.

 

[mnetwork]

If the pistons were spot less at 124k or whenever I checked them, a few more thousand miles didn't do anything. I've seafoamed the car recently too.

 

[olmytsi]

I think it's also related to the heat. During those pulls, your coolant temp starts at 195 and then after the first pull, it climbs to 200 and then 206 and you are going wot to 120 mph which is a decent amount of load.

I personally try not to do pulls unless my temps are under 190.

I swear your log reminds me of my old motor. Same timing i could get away with, random knock and had to run it really rich.


Check compression just to see.

 

[mnetwork]

I think it's also related to the heat. During those pulls, your coolant temp starts at 195 and then after the first pull, it climbs to 200 and then 206 and you are going wot to 120 mph which is a decent amount of load.

I personally try not to do pulls unless my temps are under 190.

I swear your log reminds me of my old motor. Same timing i could get away with, random knock and had to run it really rich.


Check compression just to see.

How was your compression on the old motor? Would lower compression increase knock?

I did a compression test last month and came up (starting from cam gears) 165-170-175-180. It was weird because cyl1 was a little low and cyl4 had brand new compression.

 

[olmytsi]

It was shit... 120-115-110-105 or something like that.

Not sure if lower comp increases knock per say, but an unhealthy motor will probably tend to knock more.

Yours looks good.


Try doing some pulls with cooler coolant temps and see if the knock goes away.

 

[mnetwork]

I do a lot of pulls with lower temps and still get knock. I do a lot of my pulls at 186 - 193 and still get knock.

 

[olmytsi]

I don't know what to tell you. Alot of people will tell you that it is not that much knock but it is specially with that little timing and boost. Could it be related to the gas you got recently?

Have you posted it on dsmlink forums? Waaaaaaaayyyyyyy more help there.

 

[mnetwork]

I replaced the knock sensor today because it seems like it leaked a little bit at some point. Going to do pulls tomorrow or Friday and report back.

 

[olmytsi]

Cool!

 

[Evil1gDsm]

I replaced the knock sensor today because it seems like it leaked a little bit at some point. Going to do pulls tomorrow or Friday and report back.

If after replacing the knock sensor...i would first assume you checked your base timing right? If not, make sure it's set.

I would also, stop at a local gas station & pick up some race gas 110 will do & do some pulls there...

How old are you plugs? Also, kind are you using? Put a new set of plugs in...gap them right & do a few pulls & then review your plug condition.

I've found these to be the best ways to HELP solve knock issues!