I think it may just be the cold weather, but I keep hearing this slightly "tinkling" sound that seems to come from the engine bay, usually at higher levels of throttle, but not always. I can't imagine what it would be, but it's kind of annoying.

I figure it could be a timing issue or something... it sounds sort of like plinking (intake backfiring) but it's much quieter. I figured it might have been my exhaust manifold heat shield since they weren't bolted down right (half the bolts for the shield were broken off in the manifold) so I took it off to see if that was it (now they're all broken). Apparently it wasn't.

Any ideas on what it could be or how to stop it?

I also always seem to get some minor plinking if I just jab the throttle to high or full throttle (whether or not it's out of gear or in a gear low enough for acceleration), due to the advancement of the timing... my timing is set slightly higher than stock IIRC but I don't get why I would get plinking JUST from giving it heavy throttle from low RPMs/idle... unless that's normal?

If not I'd like to find a way to prevent it, as it has a less-than-positive effect on throttle response and driveability.

 

hopefully its not 'pinging' from detonation, more info on your car please. turbo or na? mods? ect. how much did you advance your timing?

 

if you have a T2 you might be detonating...

 

It's an NA, so I can't imagine it would be detonating. It doesn't sound like detonation...simply "burping" through the intake (backfiring... not to be confused with afterburning).

 

My one theory is that perhaps it's just running a bit lean due to vacuum leaks, which might also be causing my intake to constantly hiss at idle (also annoying).

This doesn't really account for the tinkling... just for the plinking.

 

Hmm... it may or may not be something mechanical banging around (although I can't imagine what) since it's far too quiet to be backfiring (much less detonation).

I can't figure out what it is, and it doesn't seem all that detrimental, so I'll just live with it for now...

I suppose it could be something like the engine mounts or the exhaust, although this seems unlikely.

I also think I may have an exhaust leak at the manifold... damn it all to hell.

 

if this were a piston engine I would say that your timing could be off causeing the fuel/air to ignite before the intake valave was closed, but in this case I dont see how that is possible unless the timing was set perfectly wrong... I could even be wrong on that.


BC