Getting a ton of knock

[Stealth93]

A little background, picked up the car from a member here. Replaced the knock sensor with a new one, old one was mushed. Put a 2.5 to 3 in turbo back exhaust on it. Fixed the injector malfunction CEL by replacing the pigtails. Fixed some intercooler piping leaks. Fixed the passenger side output shaft seal after dremeling the outer half of the seal surface because someone used a hammer of something installing a previous seal. Also tightened the turbo to manifold bolts and O2 sensor because they were loose. Next is to fix the damn engine oil leaks, but that is for another day.

So after all of that I was super jacked to at least drive the car around but I am getting a ton of CEL lights (ECMLink) do to the knock sensor picking something up on and off of boost. So I believe I might be running lean. Any suggestions on what to check next?

 

[ILL122]

Get something to monitor fuel. i.e. wideband or at the least a E.G.T. Pull the plugs to see the condition of those first and foremost. You can look at the back of any haynes manual to see whats going on with the plugs.(sparkplugs never lie). That will tell you if youre running lean.

 

[evil tsi]

if its a manual, i have seen other posts were something has let go in the clutch set up causing the knock sensor to pick it up. also, what is your timing set at?

 

[92AWDHX40]

Gotta get a wideband, do some boost leak testing too.

 

[Stealth93]

I set the timing when I first got the car but not since the exhaust and leaks I found, I'll double check that.

Didn't really want to get a wideband yet due to the cost of other stuff but sounds like I might have to. Is there a way to globally up the fuel in DSMLink in the meantime?

 

[evil tsi]

I set the timing when I first got the car but not since the exhaust and leaks I found, I'll double check that.

Didn't really want to get a wideband yet due to the cost of other stuff but sounds like I might have to. Is there a way to globally up the fuel in DSMLink in the meantime?

use the ecmlink wiki, it has the global settings and deadtimes that will get you in the ballpark.

 

[ILL122]

Check base timing, boost leaks, look for lean conditions on plugs and gapping. what octane fuel are you running? Real bad lifter tick can cause some degree of knock too. Especially if you are running solid mounts.

 

[Stealth93]

I am just running pump premium which is 91 around here.

Car is supposed to have 3G lifters and it is quiet as I used to have a 91 Laser 2.0 N/T back in the day and its not comparable.

I'll check the plugs, just put them in 10 miles ago, but I'll check and hit the timing up also.

Edit: Also all cylinders are 150 on the compression test.

 

[bryanwheat]

It's really impossible to tell what the a/f ratio it without a wideband. Even though you set dsmlink up with the right settings it isn't always right. You should of got a wideband before even considering dsmlink.

 

[Stealth93]

Ok haven't checked for boost leaks yet but drove it to the tag office. 1st and 2nd gear I can spool up to 14 psi which is my goal, 3rd hits 12 psi and backs down to 8-9ish. So I definitely have a leak. So wouldn't a leak cause rich conditions with the ecu thinking more air is reaching the cylinders so more gas to compensate?

 

[GRAVEDIGGER]

Did you check the back of the knock sensor for the black goo of death? Maybe it just needs replaced. A wideband sensor is going to be a necessity for tuning though, so you better plan on that soon.

 

[Stealth93]

The knock sensor is new, old one definitely had the goo of death

 

[92AWDHX40]

Well thats good a wideband to me would be a first before many mods or a few i did that,wish i did that before i started buying parts. Got one now, and link to tune whatever comes my way it helped out so much as a logger cel detector and damn near just about everything else down the road.

 

[Stealth93]

Well found my boost leak, the pcv valve flowed equally both ways. I'll fix and post back.

 

[MuffinMan7580]

Ok haven't checked for boost leaks yet but drove it to the tag office. 1st and 2nd gear I can spool up to 14 psi which is my goal, 3rd hits 12 psi and backs down to 8-9ish. So I definitely have a leak. So wouldn't a leak cause rich conditions with the ecu thinking more air is reaching the cylinders so more gas to compensate?

Super rich conditions can cause knock as well. It's more prevalent in diesels, but it happens in gasoline engines as well. Diesel-heads call it "fuel knock".