Car problem

Menthis

Menthis

Menthis

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24 Aug 2010
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Had this problem a while now but dealt with it, but is really starting to annoy me now.

A little hard to explain but car seems to rev up when well it shouldn't, When i first come to a stop it will rev to say 2.5k then after a while it will drop back down. and also on gear changes it revs while out of gear! It's also a lot worse when cold or wet! but is still bad when hot...

Its a ford focus 1.8 zetec 2001

Any help?

Thank you
 
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Menthis said:
Is the focus zetec a cable operated throttle?
A few people said it could just be a sticky cable.
Click to expand...

I had this problem on an old Car, the Throttle cable was hydraulic and was not releasing, so the car would think the throttle was fully pressed, changed the cable and it fixed it.
 
Have had the idle control valve cleaned and cleaned the MAF sensor myself seems pretty clean in the first place.

Both have not helped
Not sure what else it can be other than the sticky throttle cable. Is it easy to replace myself?
 
I wonder if you have a vacuum leak?

Do you have access to an OBD tool? It would be interesting to see what you short term fuel trim is @ idle, if it's high +10%) then drops to 'normal' as you hold the car at approx 2500-3000 rpm then you have unmetred air getting past the maf.

I'd also expect to see a long term fuel trim of around +7% if it's the case.

*edit* car has to be warm & the o2 sensor operating in closed loop when testing!
 
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I dont know if the Focus has one but I've heard of this kind of problem on VAG cars being caused by a dodgy clutch pedal position sensor.
 
MatteH Oxford said:
I wonder if you have a vacuum leak?

Do you have access to an OBD tool? It would be interesting to see what you short term fuel trim is @ idle, if it's high +10%) then drops to 'normal' as you hold the car at approx 2500-3000 rpm then you have unmetred air getting past the maf.

I'd also expect to see a long term fuel trim of around +7% if it's the case.

*edit* car has to be warm & the o2 sensor operating in closed loop when testing!
Click to expand...

I don't know what an OBD tool is, not really too technicall when it comes to cars.
What do you mean by fuel trim?
 
A faulty speed sensor causes some very odd idle issues on the Focus, such as the idle increasing if you simply coast forward slowly e.g. in a a queue of traffic. A bad VSS (vehicle speed sensor) will also often cause the speedometer reading to drop intermittently, but this doesn't always happen.
 
Faulty speed sensors on Fords nearly always cause them to cut out or the idle to bog down, not cause a surge in idle speed. Afaik the clutch switch is just a simple on/off safety device for starting the car or to turn off the cruise control. Not sure if Europe has the switch tied into the starter cicuit though?

OP, an OBD tool is simply a computer (either PC or dedicated unit) which allows you to access real time information from the various sensors located on your vehicle. A lot of the time you will need an additional labscope to see the various signal waveforms, any variation from 'normal' is a fault within the circuit you are analysing. You really need a technician with Knowledge & experience of Ford sensor diagnostics post 2001, unless you want to play the swapping out parts guesswork game. Faults will always provide evidence to those who know what to look for.

I left Ford in 1999, most of my experience would carry forward but things do change quite a bit, even over the lifetime of a single car model. Especially sensor 'types' & their operation.
 
The only thing i experience is when i slow down to come to a stop it will sit at the revs it was at from being in gear, and go up slowly till about 3000 revs, then when i finally come to a full stop it will drop down.
Plus i can never have clean gear changes because it revs up during the change of gear. Its weird because some times its fine.

It also seems to idle fine, doesn't jump around sits at about 900revs i would say

Looks like ill have to take it to the garage to get it fault read i guess, i had a mate put in a one of these fault code readers but it gave no errors..
 
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