AX 1.0 running issues

[Kitch]

Posted: Sat May 12, 2007 5:45 pm Post subject: SPFI 1.0 running problems

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On my aunties AX, which is a 1.0 Dimension on a P reg 1996, we've got some running issues.

In a nutshell: The car starts happily from cold and run happily for around 5-10 mins as it warms up, but it does tend to idle a wee bit high. There are some very faint flat spots as you load it up, but nothing major. After the 5-10 min period the idling has got up to around 2000rpm, and if you rev to about 3k and then release, the engine sometimes splutters and cuts out totally. It then takes another 5-10mins to coax it back into life and it eventually fires up one cylinder at a time.
After this, it runs again but starts idling even faster, all by itself. I watched the throttle body unit and the butter jams open at this point, and the throttle cable is slack. It isn't sticking externally as far as I can see.

Basically, anyone heard of this before? Theres a black Bosch box on the front of the unit which I unplugged while it was fast idling and it returned to normal for a short time, but was soon playing up again.

There's no K light on, but the light does work.


Any ideas?

Cheers

[AndersDK]

This sounds like a worn throttle potientiometer. Or if present : a worn out throttle stop/idle switch.

If the butterfly is seen to 'hunt' for a stable position, then it is exactly the throttle pot that has worn a hole in its carbon track. Known to give 'ghosting' revs like the engine has suddenly got a life of its own.