crash

Driving down to Bracknell yesterday and I noticed a vibration coming from the front of the car under very specific conditions. Namely, these were:

70 - 78 mph
4K - 4.8K RPM (6th gear)
Open throttle (i.e. accelerating)

The most bizarre was the last one. The vibration only occurred when I increased throttle. That is if I held the throttle steady at 4.5K RPM the vibration ceased. Likewise, decelerating down from 5K to sub 4K RPM - no vibration.

Any thoughts? Strangely enough, didn't occur on the return trip back to London - no vibration nothing.

First encountered this after my day at Bruntingthorpe with Don Palmer. I have not taken it to the dealer as I cannot reproduce the problem on demand.

Am I damaging my car?!?

Turtle

Have you checked all the manifold heat shields? You should find some problems I had with noise from these with a search. It would help if you could describe the sound more, but it's still always hard to guess from a description.

-Brian.

crash

Hmm - best way to describe the sound would be a rapid metallic rattling at round 5Hz or so? It's quite quiet and subtle - the only reason I noticed it yesterday was due to the fact that I had the radio off yesterday.

Thanks for the comment Brian. However, if it was the manifold heat shielding would it not happen throughout the rev range and no matter what gear I had selected? What worries me is how specific the problem is.

Thought that comes to mind is that it is transmission related as it only occurs when the engine is under load - gearbox, clutch, valves?

DavidMorris14

Crash, have you checked the Library and Service Bulletin regarding the buzzing noises coming from the clutch spring ? I hade this problem and it was replaced under wnty.
Get your Honda dealer to check it.

Turtle

If the the rattle's very tinny and metalic, it could be the same problem. That was rpm specific - trigger by a combination of some resonance and the car being at a certain temperature. There are a lot of heatshields - top visible on the manifold, 2 titanium low down near the bulkhead, plus an additional one between the body and the manifold/cat. It was the 2 titanium ones, plus the top one that caused problems. They're made from a couple of stampings spot welded together - it's possible it's just one of the spot weld's has failed allowing the stampings to vibrate against each other.

-Brian.

s2000db

Other alternative is that it might be the gear lever rattling, it might need greasing and retightening. Next time it happens apply a bit of pressure to the top of the lever and see if it cures it.

DB