Knock/Cylinder Head

[DanThMan1983]

I have been having alot of problems with knock since I put in the new engine. I did a boost leak test, ive put in good fuel, ive changed plugs, regapped them, put in the revised lifters. I was wondering if anyone has had problems with DKS cams? The cylinder head is a remanufactured cylinder head when I bought the car and upon rebuilding the engine I had a valve job done on the cylinder head, so maybe the valve is sitting too far up in the cylinder head and the springs are binding? the retainers are hitting the guides? Let me know what you guys think.

 

[Street Surgeon]

How new/old is your knock sensor Dan, I was having a similar problem about a year and a half ago. Turned out my intake manifold was absolutely caked with oil scum etc. from a blown seal in the turbo. What kinda boost and gas are you running, got any logs?

 

[delta448]

Did you maybe get the T-belt off by a tooth or two? Check base timing? Has the head been shaved or the block decked? Do you know your exact compression ratio? Did you ever run the engine before you installed the DKS cams?
Under what conditions is it knocking? Is it constantly or maybe just over a certain boost level?

I think if springs were binding or retainers hitting guides, you'd have some valvetrain breakage and the engine would be limping quite badly.

 

[DanThMan1983]

Did you maybe get the T-belt off by a tooth or two? Check base timing? Has the head been shaved or the block decked? Do you know your exact compression ratio? Did you ever run the engine before you installed the DKS cams?
Under what conditions is it knocking? Is it constantly or maybe just over a certain boost level?

I think if springs were binding or retainers hitting guides, you'd have some valvetrain breakage and the engine would be limping quite badly.

Tbelt is dead on, I set base timing, 5* BTDC, dont know the exact compression ratio but i have weisco 8.3:1 pistons and the block was decked, never ran it on any other cams, it knocks at part throttle not in boost on 91 octane fuel. This will help ALOT here is an older post of mine trying to figure out the same problem. I have put in the revised lifters since then.

 

[DanThMan1983]

How new/old is your knock sensor Dan, I was having a similar problem about a year and a half ago. Turned out my intake manifold was absolutely caked with oil scum etc. from a blown seal in the turbo. What kinda boost and gas are you running, got any logs?

Knock sensor is brand new.
12lbs of boost but it happens before i ever get into boost, got logs in my post above.

 

[delta448]

Try just disconnecting your narrowband A/F gauge first, in case it is degrading the signal or providing a short across the sensor. If that doesn't work, check your front O2 sensor.

I am having a bit of trouble with the log you linked. I can make no sense of the front O2 voltage, especially in relation to knock, so I think you may have some wiring issues with that narrowband gauge. Either that or your sensor is dead and you are dumping a buttload of fuel into the engine and getting rich knock. Have you done a boost leak test?

 

[Module Unknown]

Just because you said part throttle knock, I'm going to share my knock story. For the longest time my car would knock on 91 octane in 3rd through 5th gear at around 15%-25% throttle, just lightly accelerating (little to no boost). Trying to pass cars on the freeway using a little bit of throttle scared me (it was the worst in higher gears). Of course, going WOT also caused the car to start knocking like mad. Upon further experimentation I found that if I would just hold the throttle position around 80% I could build boost, hold it, and not knock.

Anyway, my problem turned out to be my fuel pressure regulator. Fuel pressure was slightly lower than it should have been, and I'd imagine that it wasn't working correctly under boost (or near it), I'm not entirely sure what it was doing since I had no way to monitor it while in the car. I swapped it out with an Aeromotive regulator and have been happy ever since. I probably could have just replaced the stock part, but figured why not upgrade if I'm spending the money. The old regulator must have been sticking or something (if even possible). When I removed it, the return line was bone dry. I was unable to entirely depressuirze the system either before uninstall. Diconnected the fuel pump, started the car, opened the fuel door, started the car... car would keep dying, but I was able to repeatedly start it. Somehow the stock regulator was still holding the system at 20psi. :-\ dunno, but whatever, I'm rambling.

 

[DanThMan1983]

Just because you said part throttle knock, I'm going to share my knock story. For the longest time my car would knock on 91 octane in 3rd through 5th gear at around 15%-25% throttle, just lightly accelerating (little to no boost). Trying to pass cars on the freeway using a little bit of throttle scared me (it was the worst in higher gears). Of course, going WOT also caused the car to start knocking like mad. Upon further experimentation I found that if I would just hold the throttle position around 80% I could build boost, hold it, and not knock.

Anyway, my problem turned out to be my fuel pressure regulator. Fuel pressure was slightly lower than it should have been, and I'd imagine that it wasn't working correctly under boost (or near it), I'm not entirely sure what it was doing since I had no way to monitor it while in the car. I swapped it out with an Aeromotive regulator and have been happy ever since. I probably could have just replaced the stock part, but figured why not upgrade if I'm spending the money. The old regulator must have been sticking or something (if even possible). When I removed it, the return line was bone dry. I was unable to entirely depressuirze the system either before uninstall. Diconnected the fuel pump, started the car, opened the fuel door, started the car... car would keep dying, but I was able to repeatedly start it. Somehow the stock regulator was still holding the system at 20psi. :-\ dunno, but whatever, I'm rambling.

I have an AFPR

 

[DanThMan1983]

Had a friend help me tune it today, MUCH MUCH better but need help ill post my new log and safc settings when I get home from work! woohoo!