help with strange problem

[stainesy]

I just changed the alternator on my brothers seat cupra 1.8 20v. Everything works great but now when I turn the ignition off and take key out the car carrys on running.
When ignition off and car still running I put it in revurse with clutch still down and engine turns off.
But if ignition on and car running goes into revurse as normal.

Any ideas what's going on?

[justalex81]

did you disconnect battery when you changed it?

[stainesy]

Ooooops no I didn't lol.
Why's that?

[stainesy]

You recon it might just need to disconect battery over night and put back on in morning to reset the ecu?

[Thom89]

I'd say you have a wire on wrong! sounds like the alternator is still feeding the ignition system, whether its switched on, or off!

Thom

[salsheikh]

to reset the ecu you only need to leave the battery disconnected for 15-20 mins. check all the wires again to make sure the right connections have been made.

[stainesy]

There's only 2 connections. The oval clip that only goes one way and the thick earth cable that's it.

[dazzawest1987]

Are the dash lights staying on or is it just the engine continues running

[Dan_GTi8v]

The big cable should be going to positive not earth surely? At least it does on my 20vt. Not that that would cause the problems you describe

[stainesy]

no the dash lights go off and even ignition goes off and nothing works like windows wipers and normal stuff that comes to life when ignition off its just that the engine thingyinues running.

maybe it is the positive cable just said it was earth coz its black anyway every cable is in the same place as they came off old one. cables are fine.