dropping/fluctuating idle, almost stalling WS

[Samtheband]

Hi Guys,

my mrs has a WS fiesta zetec, and has been telling me her car has been idling wierd on and off....


Basically, its when she's at the lights just sitting with foot engaging the clutch.

It idles fine, then too low, then fine again, almost stalling.

It didn't happen on the way home from her work, but it did all the way to work.

Any ideas, or suggestions?



Oh, it's a 5speed manual obviously

It's only done 30,000kms or so...and it well looked after.

[GoesLikeAZetec]

Not the air con engaging and turning off?

[Samtheband]

Nah.I don't think so, it's more rough than that.

[Fiesta God]

Mine occasionally drops revs at idle, but seems to only happen when the engine is running hot (has been worked a little too hard ... hehe ...). Nothing concerning though.

It certainly doesn't drop nearly enough to get to stall point.

Not sure what the cause would be?

[GoesLikeAZetec]

does it still do it if she takes her foot entirely off the clutch and leaves it in neutral while waiting at lights?

[paulo7]

hi,
an old car of mine did this and the mechanic found a faulty sensor in the intake system. I think it was the oxygen sensor in the throttle body or just near it.
You'll probably have to get it checked out...

[Samtheband]

UPDATE:

So this is now happening again. The engine light came on, and it threw up the 'camshaft position sensor' fault code.


The dealership 'couldn't replicate fault' of the rough rough idle, sounds like a chug chug chug kind of sound.....

would it be a faulty sensor? Any other ideas? I want this solved, and am sick of dealers sitting on their hands....

Any help would be great lads.

Ta,

Sam

[Russ]

What fuel are you running it on ?

[Fiesta_Man69]

Ford released a PCM update for the Fez that was supposedly for a similar chugging when cold but yours sounds much worse than a computer glitch. How long has it been doing it for? Could just be a real dodgy tank of fuel or indeed faulty sensors. If you saw the error appear on the dash then the error logs and the Ford service department can recover the data, apparently. It's worrying if they can't.

[Samtheband]

It's always on bp ultimate. It isn't bad fuel, and they rekon they can't fault it.....even with the error codes. It's gotta be a dodgy sensor I rekon. It's been doing it on and off since she's had it but never this bad.

[Samtheband]

Would replacing the camshaft position sensor cost much? Tempted to just get it replaced somewhere else if they won't listen to me.

[Russ]

Not sure on the cost of the replacement sensor but the labour shouldn't amount to much providing it's not buried and they don't have to remove too many other things to get to it, it sounds like a relatively easy procedure which you could do yourself once you find where it is. Here's a couple of links to give you an idea of how to DIY, the only thing it will need is to have any current errors cleared

If it was showing that an error had been logged when you took it to the dealer then I would be tempted to contact Ford H.O. via phone and explain the situation to them, especially with it being a potentially life threatening issue should it stall when trying to merge into traffic or pull out from an intersection, from what I have read on the net regarding these sensors it's unusual for them to malfunction like this but not unheard of and if it completely carks it you'll be left stranded for sure :(

http://www.ehow.com/way_5448202_cams...rocedures.html


http://www.ehow.com/how_6234278_repl...on-sensor.html

[Samtheband]

yeah thanks for that Russ. I have been doing some reading regarding replacing the sensor myself. But I will let them try and 'fault it' on monday, and if no result I will be calling Ford head office for a resolution.

[Russ]

Originally Posted by Samtheband

yeah thanks for that Russ. I have been doing some reading regarding replacing the sensor myself. But I will let them try and 'fault it' on monday, and if no result I will be calling Ford head office for a resolution.

No worries mate, best of luck with it

[photn]

also check your coil pack. My 2003 focus is doing the same thing but mine actually stalls. had a mate of mine who had same issue as you and once replaced the coil pack issue was gone. im replacing my coil pack this weekend.

[Samtheband]

yeah they are replacing the camshaft position sensor. (that was one of the fault codes that came up)...

The other code was 'crank angle sensor'.

Can anyone explain what the difference is?

They both effect the idle yeah? I figure if we replace one, then if it's not fixed, the other one will be to blame?

What does the coil pack have to do with idle? I don't know much about coil packs at all.


Thanks.

[Russ]

From what I could find on Google

A cam sensor tells the computer when number one compression stroke is happening, the crank sensor tell the computer when to fire the sparkplugs.

A faulty coil pack can cause rough idle among other things, I would suggest that if after replacing the sensor / sensors if the problem remains it would probably be worth checking

[Samtheband]

yeah cool. My bet is on the cam position sensor. But we'll see. They haven't been able to replicate the problem since having the car, only the engine light..... (but that was on when I brought it there)

[Samtheband]

UPDATE:

So they have replaced the 'crank angle sensor', so time will tell if that fixes the problem. I have my SCT Xcal3, so if another code comes up, i'll be able to at least see it before Ford does.


My bet is, it was the camshaft position sensor, but if I'm wrong I'm happy to retract that statement.


Fingers crossed.

[Fiestaman]

Had an idling hiccup on my WT. Has done it twice so far but dealer could find no fault. When idling revs go from 800rpm to about 1200rpm up and down for about 10 seconds then return to normal. Aircon not on at the time.

[Samtheband]

Well I have heard that camshaft position sensors were notorious on the pre 2008 fiestas. So might still be an issue?

[firko]

had the same problem its the throttle position sensor that is also attached to the throttle body its a 10 min job a used one from a wrecker is about $135 a new one is $300 from ford