Knock in 1st gear

[xveganxcowboyx]

Around the time my 14B ws dying I noticed heavy knock in first gear and continually lessening knock as the gears got higher (43-1, 20-2, 8-3, 0-4&5 or similar). I replaced the turbo with a B16G and got a 2G manifold. For the most part things got better. For some reason I'm still seeing knock in first gear. Anytime I even come close to boosting I can feel the timing being pulled. I haven't been running it hard in that gear, but even in partial boost/partial throttle I'm seeing 20-something counts of knock. I get little to no knock in other gears.

:confused:


*edit* It may be related to a problem I've been having where the O2 sensor reads 0.03 or 0.05 sometimes at idle, but seems to cycle fine otherwise. I changed O2 sensors with the turbo (one came with the new one). I had the same O2 sensor issue before and after the change.

[xveganxcowboyx]

Awww, come on guys. I need a little help here. Pretty please. :)

[Kracka]

O2 sensor is not related to knock counts.

Have you had your car tuned? That would be a good place to start.

[xveganxcowboyx]

Completely lacking in tuning hardware right now. Just bought an evo 8 fuel pump and injectors. Will be looking for an AFC right away. Until then....

I don't think this has anything to do with tuning though. It just started recently without any major changes. I mention the O2, because it does it at partial throttle as well, when the O2 actually means something to the ecu.

Unless I'm running rediculously lean I think it's a false reading, because it starts at anything above 0psi or even slightly in vacuum.


It's also worth mentioning that my mileage dropped about 5-6mpg around the same time, but I think that's just due to pulled timing.

[94talonawd]

It would help if you tell us what has been done to your car.

Have you tried diagnosting it yourself first? What all did you check already?

[94talonawd]

So you have Evo 8 fuel pump and injectors in your car and nothing to tune with, correct??

Tsk tsk tsk..

[94talonawd]

Oh yes, and it seems to me that this is a new car?

[JET]

If the last post is correct, then you are quite rich, which would lead to the knock in the lower gears. You can knock from being too rich, which would be the case with bigger injectors and no tune.

[niterydr]

What are the mods on the car?
Rich "knock" and lean "knock" can both occur. One is more of a cylinder miss-fire the other can be detonation. Both are very bad for power and longevity of the motor.
"knock" per gear could also be a load change or possible drivetrain noise.

[xveganxcowboyx]

No, I have ordered the evo 8 fuel pump and injectors. The fuel pump will be going in as soon as I get it, but the injectors will wait until I get some fuel control.

The car is a 91 TSI AWD. Big 16g, 2g manifold, 3" exhaust, boost controller set at 14psi, rewired stock fuel pump, egr and vacuum lines removed and capped, FMIC (a few small leaks, but nothing major). I can't remember everything right now that's going on in the engine bay. No major changes. Compression is low, but stable (110 to 120) which allowed me to run 17-18 psi on my 14b with no knock whatsoever.

I have tried to figure it out on my own, but have come up short. When it was knocking through the lower gears (most in first, but lots through third) I thought it was my dying 14b causing it. The knock was reduced when I changed the turbo, but I'm still having problems. The problem is it started without any major changes being done by me and I can't think of what would cause this condition.

So to reiterate the symptoms: Knock starts at any boost in first gear at both partial and wide open throttle. Rises to mid twenties at least which causes timing to be pulled heavily (car feels very doggy). I may be getting a little knock in second as well. Third on up runs smoothly with no knock until I start running out of fuel.