When the car is cold it idle's around 1500,when it warms up it drops to around 750,when it gets hotter it goes up to around 1200 and seems to stay there until it gets cold again???????

 

Any ideas?

That's what it's supposed to do. There's a table in the ECU that gives idle speed at different RPM, don't have the figures handy, but if it's hot enough to bump it back up, it's too hot. Or your temp sensor is faulty.

I'll double check the figures for you when I can.

Cheers John

 

Alex

Alex

 

Mine has an errattic idle.....from cold start it runs at about 1500 rpm......then after running for like 1 or 2 mins...tickover at 750 rpm......then during the 6 mile run to work...most of the time either the car ticks over at 750 rpm all the time...or at between 750 and 1200 rpm......but after much messing about with temp sensors etc i think its my throttle potentiometer/position sensor on the rh side of the plenium as when i stop at work..lift the bonnet and hit the sensor before mentioned...the revs drop to 750.

 

 

HTH (and makes sense)..........John Crisp

waggle the connector under the tps, the one thats cabled to it not the connector direct on it, when its ticking over too fast. Mine always settles down to an even 700 when I do this. Typical zed iffyconnectoritis.

also could be the idle control valve at the rear of the plenum. mine used to do this until i removed & cleaned it (careful as there are small springs in there ;))

 

i would try (in order)

 

disconnect the battery for 30 mins+ to reset the ecu while cleaning the throttle bodies with carb cleaner.

clean the connectors on the temp sensor & TPS

check TPS voltage reading & temp sensor resistance - replace if ness

remove strip & clean the idle control valve