Choke system

[zippy500]

I know the choke is all controlled by the ECU. My question is, is there a mechanical part to it or is it all controlled by electronics. I think mine may be sticking on. The reason why I think this is cos the revs stay at about 1300 rpm, if I switch off when warm and re start it runs much better and stays on 1000 rpm. Any thoughts?

[GasBlaster]

Have you tried cleaning the stepper motor? Seems to solve some idling speed problems.

[zippy500]

Done that, no difference.

[GasBlaster]

Fraid that's the limit of my technical know-how!

[JeffGleed]

I have got a pre Cat 4.0 and it does something similar. Except it's worse if I turn it off when warm (tickover has been 2800RPM!!). I have had the stepper motor cleaned, also with no effect. Is this stepper motor the only thing which controls the tickover?

[shpub]

It is all electronic based on sensor inputs including the road speed. Idling speed is not the same as choke BTW which is enrichment during the starting phase. The ECU effectively lengthens the injector pulses to increase the fuelling.

You can get very quickly into the "I'll replace the complete system through trial and error" syndrome which makes the dealers/motor factors richer but probably won't do anything for your car. If it is minor( sounds as if this is) then it might be worth waiting until a service and a dealer can plug in the appropriate test and diagnostic equipment. The components are also expensive and several hundreds of pounds can quickly evaporate with the trial and error method.

Steve
www.tvrbooks.co.uk

[zippy500]

I have checked my base idle wich was miles out previously and the stepper motor appears to be fine. Ill wait until service time. It is bearable for the time being. Thanks chaps. It seems to run so much smoother after an engine switch off. Probably a sensor somewhere.