Strange problem

[daktona]

hy, I have a very strange problem with my car, it starts relatively good and idles normal at around 850 rpm, but if the car is moving and i put the gear in neutral the revs wont go down to idle but stick to 1200 rpm, if then I brake and the car stops the revs go down to 850 rpm. It this is normal for an Escort ? I bougth the car like this.

[ScORTED]

how often do you coast along with the car in neutral for that to be a problem... does it stick indefinitely at 1200rpm? if so i'd suspect your iscv to need a clean, also try it with your vss unplugged and see if the result is the same

[daktona]

thanks for your quick answer. When I come home from work there is a little hill about one mile long, when I go down the hill I put the car in neutral for a little fuel economy and the revs stick to 1200 all the way down until I brake and stop the car, then the rpm goes at normal idle at around 850

[Markt8]

Had this on my escort gti and was just the idle control valve give it a clean

[etrebus]

Had this on my escort gti and was just the idle control valve give it a clean

had this same prob on fiesta revs would stick at about 1000 turned out to be vss on gear box by disconecting it it cured the fault but then it stalled when slowing to a stop quickly changed it all fixed though couldn't realy see what could go wrong with it its only a magnet hope this helps

[SteveB]

Revs holding up while the car is moving is correct behaviour not a fault.

[daktona]

Thanks for the replies but I'm kind of confused now, it's normal for the revs to stick while the car is moving or not ? Anyway I'm going to clean the icv as soon as the outside temp. get a little higher because sometimes (one in ten) my engine starts fine and after 10 or 15 second it stops completely, it's like I turn the ignition off, also I'm going to change the vss sensor with a second one from the scrap yard to see if that cures my problem.

[SteveB]

The revs hold up at high idle to prevent stalls between gear changes and also to lower emissions. When you are coming to a stop at a junction the revs hold until the vehicle speed drops below a preset figure and then the revs drop to normal idle. This is correct operation.

 

Your habit of coasting down a long hill - so closed throttle with high vehicle speed - is confusing the hell out the engine strategy. Because of the high road speed the ECU is expecting a gear change and so holds at high idle.

 

Disconnecting the VSS will 'cure' the problem but will make the car drive less smooth and may lead to stalling when changing gear especially with a cold engine.

[ekkie7]

So that is basically the sensor on the gearbox doing it, mine does something like this but when you come to a stop it drops below 500rpm then jumps back up to 950rpm plus we its idling its seems up and down but only slightly,so im thinking idle control valve needs a clean,had an astra mk3 that was doing this but worse turned out to be oil getting back in the inlet manifold making it run like a nail, no thanks to the egr valve and cam breather.

 

Sorry im a nonce vehicle speed sensor :doh:

Edited March 3, 2011 by ekkie7

[Flash4203]

You should not coast down a hill with the car in nautrel that's deemed as driving with limited control of the vehicle,

Stick it in 3rd or if really steep 2nd keeps the car at constant speed and the fuel consumption is hardly anything as your foot is not on the gas pedal.

 

Free wheeling ( coasting) is bad as no assisted engine braking. [limited engine braking is better than no engine braking at all]

 

That's my view

 

Car oem brakes are not the best anyway

Edited March 4, 2011 by Flash4203

[ScORTED]

engine braking on modern vehicles is very limited, but you are correct about not coasting