Metalllic Sound

[simon gray]

Driving the car on Monday I heard a 'metallic sound' for a couple of seconds under reasonably hard acceleration from about 4000 rpm to 4500rpm.
It sounded like something was 'loose' under the bonnet and rattling for a couple secs
Anyone any ideas

Thanks as always

[kevinday]

Sounds like pinking to me, what fuel are you using?

[simon gray]

Optimax- so unlikely. i thought it miht be pinking but it sounds just a little too metallic for that

Thanks

[digga]

No that is probably pinking - it took me a while to be convinced that somthing wasn't tapping or knocking onto a metallic surface when my car was doing it.

Even on Optimax, the car could still easily pink if, for example there's insufficient fuel pressure boost (as with mine), so it's worth getting it checked out.

Look on the bright side, if there is a fuelling problem, the car should pull even better when it's sorted!

[marino]

Driving the car on Monday I heard a 'metallic sound' for a couple of seconds under reasonably hard acceleration from about 4000 rpm to 4500rpm.
It sounded like something was 'loose' under the bonnet and rattling for a couple secs
Anyone any ideas

Thanks as always

Had exactly the same problem, Andy at APM retarded the timing for me and suggested that the warm weather contributes to the noise. Not a mechanic but I think that there is a difference between pinking and predetonation, anyway the timing was changed from 32 to 28, whatever that means, and the car has been fine since.

[rev-erend]

Simon - don't panic yet ... fuel can vary from
one tank full to the next.

If it still does it after the next tank full have
the timing re-adjusted by just a few degrees
and check it out with a road test in hot conditions.

[simon gray]

As always thanks all