Electrical problems with S2 - help please

[TVRBO]

Does anybody have experience of the following problem and could you recommend what might be wrong?

My S2 has developed an issue whereby it runs rough when just started from cold. The idle hunts as the engine misses and sometimes dies totally and stalls. The idle speed also seems to be a bit erratic. Sometimes as the car warms up from start the idle increases to quite a fast speed (2000rpm). Other times it stays more normal (750-1000rpm). As the engine warms the problems get less severe, but the occasional miss remains once driving.

Any thoughts would be greatfully received.

[entwistlea]

i've been having the same problem with my new S2, i've posted and had some great help. The main suggestions are its fuelling not electrical, clean the air flow meters, then let teh car run from cold to warm whilst idling. Also been suggested to look at the throttle pot and a friend of mine who is a ford mechanic suggested the cold idle valve could be furred....

can;t take credit for any of this, but its what i'll be trying this weekend !

[Harry1972M]

Hi - you can rule out the throttle potentiometer by simply disconnecting the electrical plug which will put the ECU into a sort of limp home mode - if it is the problem then once disconnected your engine should idle higher than normal but steady - you can use the same process on the AFM's however only disconnect one at a time - unfortunately this doesn't work on the idle speed control valve as disconnecting this places the ECU into service mode which may just be masking another fault.

Graham

[kenpage]

tvrbo i have had the same problems there are plenty of posts on here for this as already said the starting point is the throttle pot then the air flow meters then the idle control valve.the last 2 are easily cleaned with carb cleaner also check the water temp sender to the ecu not the one for the temp gauge i did all these and it now idles at 1000 rpm steady but i did all of them at once so i dont know what actually cured it
Ps this information is free and will remain in the public domain

Edited by kenpage on Thursday 3rd April 15:26

[TVRBO]

Thanks all for the tips. I'll go and have a prod around under the bonnet tomorrow and see what I can fix. My suspicions are centered around the air flow meters as they are old, and as the throttle pot was replaced not particularly long ago. I'll check the idle valve too.

Many thanks again. TVRBO

[TVRBO]

Just as an update:
I've managed to get hold of 2 replacement airflow meters and have fitted them to the S2. This has completely solved the problem! The car is right back at 100%.

Upon further inspection of the original airflow meters I noticed that the resistant measured across the pins to the variable resitor connected to the flow paddle did not give out a constantly rising value with a swing of the paddle. The values were very jumpy and suggested that the resistance tracks were warn. Upon opening up the airmeters it looked like there would be little that I could do to 'fix' the tracks, so I plumped for the replacement units. Well worth doing though, as the EEC was obviously getting the wrong messages!

Thanks again for the suggestions.

[ketvrin]

Anyone else suffering the same might be interested in this ?

http://cgi.ebay.co.uk/NEW-UNUSED-Ford-Sierra-XR4x4...

K