need help with kr issue

[shooterc5]

Whats up guys i need some advice here. I just installed my new scan guage in my car and took it for a hard run on the highway because i was curious if i was getting any knock. Well im definitly getting some. On every run consistantly i was fluctuating between 4.5 to 8.5 degrees of knock at about 75 to 100% throttle. I have a 99 gtp and my mods are 3.4 pulley, wizair intake, tb spacer, ubend, cat back, dhp, autolite 104s, and 180 thermostat. Seems like i have all the supporting mods for the 3.4 pulley and shouldnt be seeing any knock. Heres the thing though my down pipe rattles because it is a dual walled pipe and piece of the inner pipe broke free from the outer pipe cuasing an annoying rattle. Also i have a small exhaust leak which sounds like its coming from the mounting flange at the rear manifold to the downpipe. Probably a bad gasket. Could this be the cause of my knock that im seeing? The car runs perfectly otherwise. Let me know what you guys think or if im missing anything. Thanks.

[MIKES3]

You may have a little false knock. Go a get a a 3" down pipe. Also look into a DHP PCM for your car. Those 2 mods should clear all your KR with what you already have done. If you want try moving your K&N filter to your fender well. That will help a lot in getting cold air.


SOrry didnt see you had a DHP. It may be false knock. The DHP should clear about 90% knock. Get everything resealed on your exhaust and while your doing that get the Down Pipe. Thats a big restriction. Did you delete your resonator?

What did you gap your plugs at?

[shooterc5]

Thanks alot for the info. My plugs are gapped at .054 and my resonator is gone. Do you think that a small exhaust leak will cause any knock? And do you happen to know if ill be able to get a new gasket for the flange at an autoparts store or will that be more a dealership type thing? Im going to be be upgrading to the cartuning turbo kit w/ intercooler over the winter so that will take care of the downpipe when i get it. I just want to make sure there is nothing wrong with the car in the mean time becuase i know that there is no acceptable knock.

[Ripn12s]

get some race gas if possible. w/ those mods and race gas u should see no kr, if you do i would bet that its false.

[BNaylor]

If it's false knock you could check the 2 knock sensors to make sure. You can check the resistance of each sensor at the PCM connector and make sure the reference voltage from the PCM is correct. The actual device that processes knock from each sensor is the Knock Sensor Module which is located in the PCM. I've seen a defective Knock Sensor Module in a DHP re-programmed PCM .

Your readings are too high.

BTW - Also check your fuel system pressure at the fuel pressure regulator. You could be going lean at high rpms indicating insufficient fuel delivery to the fuel injectors.








Thrasher CAI, DHP v1.0 PCM, SLP Headers,
3.25 SC pulley, CAIT GMAF, 2.5 DP/Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 72mm TB,
TB spacer, MSD 8.5mm wires, Autolite 103,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials
1/4 ET: 13.210 sec. @ 104.490 mph
0 - 60 ft: 1.945 sec.