westpak

iTrader: (19)

I just installed test pipes with resonators and at first I had a rough idle and erratic performance which I think was due to an exhaust leak after install, I think that is fixed as it idles OK now but now I hear a repetative low frequency knock or thump, so I have not taken it out for a onger drive.

Would that be "engine knocking" and would it be due to the pipes and the fact that I had the timing advanced a couple of weeks ago?

I am going to the dealer tomorrow morning to check it out and back off the timing if it still advanced since some say it goes back to stock.

jesseenglish

Engine knocking usually sounds like bb's in a tin can. I'd look at the last thing that you modified. It could be that your exhaust pipes might be bumping against something on the undercarriage of the vehicle.

mprowe350

I have a ATI procharger and did not take any timing out originally when we tuned it. By doing that the motor was knocking at high rpms and under heavy load. I do have a rattle from one exhaust pipe that sounds like it could the same as yours.

jesseenglish

If it's doing this "knocking" thing at idle, it's definitely not your timing. Also, it could be a fouled plug periodically misfiring.

westpak

iTrader: (19)

Thanks guys probably just jumped the gun and got worried for nothing, I went back and took it for a ride and it is not making it any more, it was probably the exhauts being up against the body and the pulsations being transmitted to the frame. I want to go back anyway and redo the y-pipe/test pipe connection as I might have forced the y-pipe a bit to fix leak and it is probably contributing to it.

Just a little frustrated with the plenum, it needs a more solid gasket then cork or be better adhered to the plenum, it slid in a couple of spots inward maybe from over torquing so it was leaking and it was version 2.

jeffw

If only one cylinder was knocking, how would that sound? The reason I as is that occasionally around 5k rpm and up I hear a tapping noise that sounds nothing like bb's in a can. It's much more methodical than that and sounds more like someone tapping a screwdriver against a piece of metal real fast. I'm stock, btw.
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Jeff

NOZ4U

I sometimes hear it when I accelerate at low rpms in 3rd and 4th gear. It's just a single "ping" not a constant. Sounds like a engine bogging issue though or detonation I've made it a point to downshift before accelerating hard. I originally got it when I pushed the accelerator all the way to the floor in 3rd at about 2500RPM and I heard it. Needless to say I don't do that any more.

the sound was like what you would hear when your exhaust is very hot and you turn off the car. It's sounds like a paperclip or nail tapping on the exhaust tubing.