This knock is going on my nerves. I don't know what else to do. HELP!!!

[-DSM2NR-]

Ok. DSMlink has been reading knock ever since I got my car. I did several 3rd gear pulls and got knock everytime (3-19 degrees). Knock is present only above 6000rpm. I tried EVERYTHING to get rid of it. I lowered boost (from 18 to 15 pounds), lowered timing, lowered fuel etc... I even switched from a hacked maf to a unhacked maf BUT NOTHING HELPED

Here's the weird part. I can clearly smell unburnt gas which means that the car is running rich even though the a/f ratio is good, loLTFT is at -3.5% midLTFT is at -2.5%. The car also spits out some liquid black stuff out of the exhaust on startup. If I try to lean the fuel (without going over 11:1 of course) knock increases. If I richen the fuel knock decreased. What the hell is going on with this car????????

 

[daren_p]

Do you have a WB or are you just using the air/fuel estimate in Dsmlink? Are you seeing 19 deg of knock retard (I sure hope not or your lucky you still have a motor) or is that the raw knock count? Have you tried running really low boost ~10 psi, if so does knock change? Have you done a proper boost leak test? Have you checked your timing? If you just "free rev" the car to redline do you still see knock? If you do a pull to redline under mid throttle does it still knock or only on WOT. First you have to do all those tests and figure out if its mechanical kncok or tuning related.

 

[Nanan]

You could have carbon deposits causing hotspots which will drive you nuts with knock. Do a search on MCCC/Seafoam and give that a try.

The two most helpful tools you could get to help you tune are a MAP sensor and a WBO2, with out these you are tuning blind. Sure you can tune by knock or EGT but really that is like walking around in a dark room full of broken glass and waiting to step on something to figure out it is in the way.

You should be able to run 20+psi on your setup once you have your stuff straitened out.



Btw seeing as you have the Link, log all the useful stuff like coolanttemp, rpm, timming, frontO2, knock, boostest, airflow/rev, tps, and ah that should do it. Do a WOT pull from 2500 to 7500 rpm and post it either here or on the DSMLink forums, really the guys on the DSMLink forums will be much more able and willing to help then the guys here.

 

[kenamond]

You could also try NOS nitromethane octane booster or if you can find it, race gas. See if that affects knock.

Also, check your knock sensor for oozing goo. They apparently only last about 80k miles.

 

[-DSM2NR-]

I'm only using DSMlink, no WB. I did a boost leak test. There were major leaks at the bov gasket and vacuum hoses which I fixed. After fixing these I did another couple of pulls, getting the same amount of knock as before. There's still two tiny leaks I still have to fix coming from one injector o-ring and the tb shaft but these are so small I doubt fixing them will make any difference.
Running lower boost does decrease knock but what's the use of having a turbocharged car if you can only run 10psi and below.........
Timing is set to 5 degrees
I already tried adding 100octane race gas but it didn't help
I checked the knock sensor. I couldn't feel anything sticky and my hand was clean when I pulled it out.
I already applied seafoam but it didn't help at all.

Is there anything else I should know?

 

[andymoraitis]

If the knock doesn't go away with octane, my intuition points to a fuel volume issue (kinked feed or return lines, failing fuel pump, clogged injectors, leaking rail etc). There's no way you should be knocking like you are at those boost levels. Check the voltage to the pump and see what it gives you. You can even try a re-wire, but even that won't save a pump that's on it's way out.

Also, make sure that your deadtime settings for the 550's are correct in DSM Link and re-check all of your Link settings to make sure you haven't missed something. In addition to fuel supply, I'd also look at high timing as a potential issue. Try a stock 2G map that peaks at 16 degrees advance and see how that works out.

Keep us posted,

Andy

 

[daren_p]

When I saw check your timing, I ment check your timing marks to make sure they line up properly. I said to run low like 10 psi or less just to see if the knock goes away, wasn't implying this is the amount of boost you should be running. Have you tried to free rev the car to see if its a mechanical issue or tuning related? Do you get the same kncok when doing mid throttle pulls?

 

[andymoraitis]

As Daren mentioned free revving is a great way to find mechanical knock. What I'm referring to is total timing advance. If it's trying to run 24 degrees on pump, that'll make it knock like a bi***, maybe even with high octane. If the knock sensor's new I think we can rule out PK unless it's overtorqued.

 

[-DSM2NR-]

I'm not even running anywhere near to 24 degress on pump . I'm not even running 16 degress. Timing is around 11-14 degress on WOT
I'm assuming that I am getting the same amount of knock on mid throttle pulls because the check engine light flickered a couple times during this period.
The knock sensor isn't new but it doesn't have any sticky stuff on it either

I'll free rev the car and see what happens, and tell you guys all about it.

 

[andymoraitis]

I'm not even running anywhere near to 24 degress on pump . I'm not even running 16 degress. Timing is around 11-14 degress on WOT

You'd better have forged internals to run timing that low. If you haven't replaced the knock sensor, replace it or at least check the torque. The 2nd Gen sensors will fail, but not show any ooze from the back (only the 1G's did that).

Here's a thread on checking your fuel pump voltage:

http://www.dsmtuners.com/forums/showthread.php?t=33933&highlight=fuel+pump+voltage

If you can free rev the motor and make it knock and also see knock on part throttle pulls, it's the knock sensor. We talked about this a week ago through PM's and I though you would have replaced it by now.

 

[-DSM2NR-]

alright. Here's the deal. I free reved the car til 7000rpm four times. 1st rev nothing. Second rev nothing. Third rev 0.4 degrees (6000rpm) of knock and then 0.7 degrees (6689rpm).

So I guess my knock sensor is toast? And how sure are you guys that knock on free rev is caused due to knock sensor failure?