Rough Idle After Disconnecting Battery

[Reiny]

I disconnected the Battery on my partner's 2006 1.3 litre vitz before going on holiday. I never disconnected the Battery before but it is now 4 years old and getting a bit tired so I thought that it would drain if I were to leave it connected for 10 days. Upon re-fitting, the engine fired up right away but it didn't rev the way it always did. Usually, whenever we fire it up, it revs to approx. 2000 revs and dies down instantly to a smooth idle. This time it didn't. It idled and that's that. What's more, the idle speed seems to be a bit lower hence the engine sounds rough and it's vibrating. We have driven it for about half an hour. It drives fine but the idle's still rough. What could have gone wrong?

[Devon Aygo]

Disconnecting the Battery has caused the engine ECU to loose its learnt values including throttle body idle control calibration, disconnect the Battery again, reconnect it and switch on the ignition but do not start, leave the ignition on for at least 5 minutes then start the car this should allow the ECU to relearn the throttle body calibrations, if it does not then unfortunately you will most likely need a new idle control valve ( not totally unheard of )

[Reiny]

Thanks. Will try that.

[Madasafish]

I always use a plug in memory saver to save all ECU/radio settings before disconnecting a Battery.. Saves a load of hassle.

[Reiny]

You can say that again. I'm never going to disconnect the Battery again. I'm a Land Rover man and am really not used to all this fuss.

[Catlover]

madasafish

A "plug in memory saver". I can understand what it will do, but where do you get one from ie if available on eBay what do you search for?

[Raistlin]

Look here:

http://www.ebay.co.uk/itm/Sealey-12v-Memory-Saver-Diagnostic-Socket-EOBD-VS2072-/201073734956?pt=UK_Measuring_Tools_Levels&hash=item2ed0edb52c

[Reiny]

She's up and running. Sorted itself out. I have reason to believe that the battery's getting tired. I fired it up last night and it sounded better, drove it hard for a couple of miles and she's back to her good old self.

[Catlover]

good for you.

thanks for the link raistlin. Thought it might have been like a memory stick, but it actually runs off a donor Battery and keeps things "alive"