Anyone got any ideas what the problem is because the local ford dealer hasn't manged to fix after several attempts? In fact I once got the car back running far worse than when they got it and Im getting very annoyed.
Ive a Escort, about 9 years old that keeps sticking on a high idle speed of 1000-1300 or so when warm after about 20-30 minutes. It will often drop again after I blip the throttle of after the radiator fan cuts in.
Normal Idle is about 850 rpm and is usually stable. When I pull to a stop it usually stays at about 1000 rpm for a few seconds and then drops, which I am told is normal behaviour. However after a run it exibits the problem behavior and often will not drop to usual idle speed even if left for several minutes or as I said the fan cuts in.
So far several parts have been changed by the dealer including I believe the Idle speed control valve, the engine speed detector, the emission control valve and the HEGO unit. It may be very slightly better but not much.
Anyone got any Ideas what the problem really is? What should I get done next? What of the engine management system is left to replace? Mass flow detector? Engine temperature detector? Throttle position detector? ECU? I dont pretend to understand how all these work together (or If I have the right names. Is the input manifold gasket likely to be faulty, Is there a mechanical fault?
Why can't a dealer find out exactly whats wrong with all their fancy equipment? Where else can I go for advice?
The engines done about 60 000 miles, and still drives OK. The clutch will need doing soon but Im reluctant to pay out more money until the Idle speed is sorted, I've recently spent about what the cars worth on tyres, exhaust, brake disks etc.and all the above.
Arrgh Help ! (Bangs head on wall)
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I would imagine the only reason the speed drops when the fan kicks in is because of the extra electrical load on the engine.
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Common failing is the Crankcase vent valve. The spring goes weak and causes the idle speed to raise slightly. I'd suggest you check the receipts first and look for a 'valve assy' F1065894 at around £12 on the parts list. If not there go back to the dealer and suggest they change it and then try and get some money back on the bits they have thrown at it in ignorance. I change these valves regularly but they still dont stock them at my local dealer!
Andrew
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Simplicate and add lightness!!
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Thanks for the help, I'm checking things out to find out just when the problem happens. The Idle speed does drop when the fan cuts in but it doesnt go back up when it stops until Ive driven the car again or at least pressed the accelerator.
Would the crankcase vent valve (which hasn't been replaced) only cause a high idle intermittently when hot?.
I did notice somethingtoday which I will have to confirm. I was parking the car whilst showing the problem Drove car forward, High Idle. Drove car backward - normal idle, drove car forward high idle. strange. Didnt have time to look at it properly. Could be just coincidence.....
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