Alternator changed now strange whirring noise and engine light on HELP !!

[n8sby]

Hi all changed my alternator last night charged the battery up, started a bit lumpy so went for a run car seems fine to drive but i can hear a faint whirring noise when revving and my engine management light has stayed on aswell, any ideas what this could be ?

The car sat with the battery and alternator disconnected for about a week while i waited for the new one to arrive

car is a 1.9 cdt1 150

Cheers

[n8sby]

i also had the egr off and boost sensor for a clean, could this have caused the light ?

[Gavin2.6]

Read the fault code to find out what it is. Only way without guessing.

Where is the noise coming from. Find a bit of pipe and hold it to your ear then try it in various places and all pulleys to listen for the source.

Did you change the aux belt when doing the change. Could be tighter belt putting a bit of force against one of the pulleys ?

[n8sby]

managed to get rid of the light after a good blast and double checked all connections, didnt change the belt just used the same one also noticed a slight tick every so often coming from the direction of the alternator like a sparking noise