Weird Knock Symptoms

[wickedmotorhead]

I have had my car for a couple months now and all of a suddon I keep getting knock just when I get on the gas a little even when there is no boost. I would run it up to 15-17psi before with marginal or no boost no problem before. Now I can barely drive it without getting knock. I have no knock during cruising, just when I get on it a little not flooring it either. Any ideas would be great. Would this be false knock? Thanks for any suggestions.

 

[Shuterdown]

Are you actually hearing the knock?

 

[Dan Thompson]

Has the motor mounts gone?

Is the DP hitting the frame or crossover pipe?

 

[quikv6]

wickedmotorhead

I just recently experienced a similar problem, which now seems to be remedied by 2 things. The main one being a bad maf sensor. I was getting 3 gms at idle, instead of 5 or 6. I didnt think it was a big deal, until i tried to trace down my BLM's, which were at
160 idle. I searched everywhere for a vacuum leak...but I bought a known good MAF, swapped it, and blm's went down to
120 idle, along with 6 gm AF at idle. This cured most of the knock.
The other problem I had was tailpipes shifting and hitting the springs. This part was obviously false knock, so check for that too. Also...try to very fuel pressure climbing under boost. (1 lb fp for each lb of boost) ex. 43 line off at idle should climb to 58 with
15 lbs boost. Good luck...keep us posted.
Chris

 

[wickedmotorhead]

Dan,

DP? New guy here still not up on the lingo.

 

[oehm]

DP= Down Pipe

 

[HellOnWheels]

Originally posted by wickedmotorhead
Dan,

DP? New guy here still not up on the lingo.

DP= Downpipe