1997 940 Idle Control Valve

[Rversteeg]

High idle noticed when coming to rest for the first time after start up. This probably is nothing to do with Laneys problem. Cold start and drive off before the initial high idle speed had dropped. Onto motorway drive for a few miles the come off and stop at traffic lights. Idle stays high until I switch car off and restart, it's fine then.

It sometimes happens to me as well, but only if the engine was not properly warmed up before entering the motorway. Settling to the correct idle speed takes a few seconds, which can be annoying in stop and go traffic, where the "stop" time is too short. If I have driven on the motorway for a longer time, the idle speed sometimes does settle at all. I do not restart, but let the engine speed drop slightly below 800 rpm by letting the clutch slip. This seems to reset the ECU and adjusts to the correct idle speed. It is not a particularly refined system...
Rob

[Laird Scooby]

Originally Posted by deeman940

i have exactly the same problems with mine,,,like the OP i was going to send the clocks off.....
When i bought the car the owner said it works if you thump the dash but that stopped working and i don't want to be thumping my dsh regularly.
Does anyone have a link for the speed sensor?

Do you have ABS on the car? If so, is the ABS warning light coming on while driving? If not, a speed sensor isn't going to help you.

As pointed out further up in one of my posts, it's worth getting the instrument cluster out and cleaning all the connectors, find my post for the exact details as i can't type it all ou again now.

[deeman940]

Originally Posted by Laird Scooby

Do you have ABS on the car? If so, is the ABS warning light coming on while driving? If not, a speed sensor isn't going to help you.

As pointed out further up in one of my posts, it's worth getting the instrument cluster out and cleaning all the connectors, find my post for the exact details as i can't type it all ou again now.

ABS is fine Dave, but what about the high idling? and sometimes stalling?

[Laird Scooby]

Originally Posted by deeman940

ABS is fine Dave, but what about the high idling? and sometimes stalling?

If the speedo and the fuel ECU aren't getting the same signal the ABS unit is getting then the fault lies in the connectors on the back of the instrument cluster. The fuel ECU gets the speed signal from the back of the speedo.

[TonyS9]

Near stalling is not asscoiated with missing road speed signals to my knowledge.

Usual cause is dirty throttle body, air leaks etc

Worth checking for stored codes in the Fuel, ignition and ABS systems.

[deeman940]

Originally Posted by TonyS9

Near stalling is not asscoiated with missing road speed signals to my knowledge.

Usual cause is dirty throttle body, air leaks etc

Worth checking for stored codes in the Fuel, ignition and ABS systems.

i recently had it smoke tested, no air leaks! i can't remember if or when the throttle body was cleaned. i will look into it....

[deeman940]

Originally Posted by Rversteeg

It sometimes happens to me as well, but only if the engine was not properly warmed up before entering the motorway. Settling to the correct idle speed takes a few seconds, which can be annoying in stop and go traffic, where the "stop" time is too short. If I have driven on the motorway for a longer time, the idle speed sometimes does settle at all. I do not restart, but let the engine speed drop slightly below 800 rpm by letting the clutch slip. This seems to reset the ECU and adjusts to the correct idle speed. It is not a particularly refined system...
Rob

Mine never resets itself unless i turn it off and ion again.....