Odometer fine but no speedo.

[Totsy]

Hi, 

1. Month ago I had some Type of sheet metal wrapped around the timing belt pullies which I removers. Not sure if the metal came of the van or picked up from the road. There has been a whirring noise ever since, not a problem but may be relevant to the problem. 

2. The odometer displays but the speedo fails after the engine starts to warm up and the mileage doesn't change when the speedo dial fails. If I co 70mph+ the whole of the dials/warning light/odometer display goes blank. 

3. Acceleration is a little abrupt when accelerating from low revs. This has become noticeable since the timing pully problem. 

I'm thinking there may be some kind of sensor for the speedo I could check? Or the local wiring to it? Where would I find it?

Any ideas?

Thanks Lee.