my car knocks when I do a pull and start from 2k-4k in 1st-4th. if I start at anything higher than 4-4.5k, i get 0 knock. Also, if I start the pull from lower than 5k in 5th and 6th i get knock....but if i'm getting knock in a certain gear, then shift, the knock goes away because when the rpm's drop, they stay over 5k.

when I say I'm getting knock, i'm talking anywhere from 10-28 counts of knock. usually in the mid-upper teens, or low 20's.

After reading through a few threads, I went back and looked at all my knocking logs and no matter how high the knock got, the knock voltage stayed roughly the same, never getting over 2....no spikes.

so, anyone care to venture a guess? i've done a boost leak test, changed timing, and boost, replaced the DV (it was the only thing I couldn't be 100% about not leaking), did a compression check, replaced the wga, everything is fine that I can tell.

The car has been tuned by two different tuners. Very good tuners. During the first tune no knock was present at the time of the tune, then it just showed up. this seems to be an issue with people from my area getting tuned in TX, then driving back to LA because apparently our 93 isn't as good as there.

this was a common issue, and simple fix for all the other guys who were retuned today.

these problems were here pre and post tune. it seems like the knock moved after the tune though. i used to only get this issue at higher rpms and it was random. i got the car tuned though, and there was no knock during the tune, but started again shortly after....like not even a day or so after the tune.

then i found evidence that i may have a bad injector, so i replaced all four, and my tuner emailed me a new tune for the scaled injectors, but the problem didn't go away. i sent him all the logs, and my rom, and he didn't see that there was anything different from the original tune as far as i know. this was all within a few days of it being tuned. he sent more tunes to try to see if we could solve the knock, but nothing worked. the car just got slower, and slower, and slower as we pulled timing/boost, and the car still knocked relentlessly. I eventually gave up and went back to the original tune and have been driving it ever since, careful to only use part throttle, and WOT over a certain RPM to avoid the bogging.

I appreciate the tuner's help, but he was fighting a losing battle trying to diagnose a problem from 500 miles away, but he was there to help offering advice and help every step of the way and it was greatly appreciated. only wish he was closer so i could have just dropped the car off to him and ran away until it was fixed.

Well a second well respected tuner came out here this weekend, and I let them take a look at it to see if they could help find the problem. I figured it would be easier for them being able to put their hands on the car.

they couldn't find anything that stood out as an issue. we removed my engine tq damper because it was found to be rattling, and that helped the knock count a little, but it never would go completely away.

the tune now is so safe that the car feels slower at full throttle now than it did at 1/2 or 3/4 before. but WOT now feels faster than WOT before because it doesn't knock/bog/pull timing, but the car feels slow. BUT I haven't had much time at all to drive on the new tune, so my opinion of it may not be fair. These guys did a great job with what they had to work with, but I wanted to be as safe as possible until we figure out what's really going on, and the car feels a lot smoother, a lot better, just slower. they didn't have as much time as they probably needed to really pin down the problem because I had to go to work, but we will continue to investigate the issue.

the only thing out of the ordinary that we could find is that the piston top in cylinder #1 was just about spotless...shiny shiny shiny, brand new looking in a car with 170,000 miles. the other 3, black as hell man. so that COULD be an indication of knock, but i also seafoamed recently and it's possible that the first cylinder got it all and it's clean clean clean now,

OR

a coworker actually suggested this...I could have a head gasket leak. I haven't noticed any significant coolant loss, but I have noticed an increase in smoke/vapor/whatever out of the tailpipe on cold mornings, like a noticeable increase. so my next step is to refil the coolant, and watch the level

question is though, would this leaking head gasket be causing my knocking issues?

anyone with any ideas that I haven't tried already, please chime in. the only things I haven't tried yet are replacing the knock sensor, and running race gas to see if the knock goes away. thanks for taking the time to read through this, and thanks to the tuners that have done their best to tackle this monster with limited time/access to the car.

thanks in advance for any help.

Oh yeah,

MODS:
ETS V2 LICP
ETS intake
ETS UICP
Megan 02 housing
Megan 3" DP
Mil.Spec 100 cell cat
Spark Tech COP
HKS Carbon Ti exhaust
ACT HDSS/Streetlite Flywheel
Grimmspeed 3 port boost solenoid (rubber mounted because of all the clicking)

 

edit, yes I know I fudged up the title...it's Your, not You're... I was in a rush. lol

 

balance shaft delete or its out of phase?

 

I've still got the balance shaft. I don't think anyone's checked the phase, but the last time I had a timing belt job done and it was out of phase, it shook violently at anything about 4500rpm.

I don't think that's it, unless there are more subtle symptoms?

 

No, if you know the feeling you know the feeling. If it was a headgasket it will spit and sputter and spike coolant temps. I dont know what would cause it out of the blue like that other than a clutch might be going away. Odd thing to say I know, but I have had the clutch springs rattle in the cage enough to make the ecu think it was knock and almost exactly like you describe.

aaron

 

I actually read some posts about that. Drivetrain noises/harmonics causing false knock at certain RPMS....i've been reading as many threads on here as I can find about this trying to see what to try next. I'll have to look at my logs to see if my coolant temps did anything stupid during the runs I have saved.

as for the clutch, would there be any other signs of this, and is it something you've experienced with the setup I have now? The clutch actuation feels fine, nothing has changed in that area as far as I can tell.

Are you talking about shift knock? or do you just mean knocking through the rev range? I've never had shift knock.

 

knocking through the rev range. Mine wasnt slipping and drove just fine. When it was pulled we could see one of the cages was done and it had been rattling around pretty good. I did everything I could think of including c16 and it wouldnt go away. this was on a Green and 21psi when they were brand new. Replaced the clutch and the problem was cured. Not saying its necessarily what you are up against but I'd think outside the box. Have you tried racegas to see if it goes away?

 

The other thing could be air temp correction of the timing if it was alot hotter in Texas when you got tuned vs Louisiana now. Hot IAT can drop timing 2-3* and it might be it was corrected for in the map initially and if it got cooler over all, the timing is till there up top and now it wants to knock.

also check to make sure the EGR side port didnt pop off.

aaron

 

racegas, and replacing the knock sensor are the only two things i haven't tried yet. i'll be trying the race gas tomorrow. I'll also be changing the oil and checking for evidence of rod knock in the filter.

the EGR vac line did pop off, but we put that back on before the tuning session today. as for the air temps, the knock started a couple days after the original tune, but the temps were within a few degrees of each other at the time.

 

I'm at work now, otherwise I'd post the last logs I pulled to see if that would help with suggestions. I'll try to do that tomorrow when I'm off.

 

Cool

 

IMO if nothing changes when you put race gas in, you have false knock somewhere. Well at least that makes sense to me.....all things being equal race gas should improve the issue.

Let us know what happens

 

if you tried race gas and the knock goes away then its not the clutch and its the tune that needs to be modified a bit. also real knock will typically show a knock sensor voltage spike and you can sometimes hear it as well.

 

Okay, I've uploaded the only 4 logs I could find saved on my laptop. The others I had pissed me off so much when I looked at them that I just deleted them. they are not all complete logs because the car was bogging so bad at the time, I just cut the run short.

Sorry for the crappiness of the logs, I had much better ones, but can't find them anymore. hope these help give you an idea of what was happening.

 

The Ecu will drop the timing under the Ignition trim vs air temp table on hot IAT ?
and this table only activate over a certain load ?