Stepper motor, engine temp sensor or throttle sensor

Owen101 · Post by **Owen101** » 02 Dec 2005, 00:21

Hi, Ive read most of the posts regarding the stepper motor, engine temp sensor and the throttle potentiometer and am fairly convinced one or all of these things is the cause of my problem.

Ive an old 94 L reg 2.0i volcane 8v and is exhibiting the classic and well documented symptoms:

-wont idle when cold (once warms up revs 'hover' around 1500).
-cuts out regularly approaching say lights after lifting off on throttle.
-on and off erratic tickover with revs rising and falling between 1000 and 3000rpm. usually the revs stick fairly high on tick over.

I'll try cleaning the stepper motor but whats the best way to test and confirm whether the problem is with the engine temp sensor, the throttle sensor or even the map sensor?

thanks

Clogzz · Post by **Clogzz** » 02 Dec 2005, 10:44

Engine stopping when taking foot off the accelerator is also possibly an air leak into the vacuum.
Check all those little hoses around the manifold for tightness.

Owen101 · Post by **Owen101** » 02 Dec 2005, 13:22

Also when I say 'wont idle when cold' I mean the car immediately cuts out should you take your foot off gas. Once warms up, doesnt cut out but get the erratic revs.

Im guessing the stepper motor wouldn't be responsible for it cutting out when cold yeah?

Clogzz · Post by **Clogzz** » 02 Dec 2005, 14:10

Owen101 wrote:the stepper motor wouldn't be responsible for it cutting out when cold

Don't have any experiences with stepper motors.
Vacuum leaks are still my favourite.
Unless you already went through this current thread, here may be some ideas:

http://www.frenchcarforum.co.uk/forum/v ... hp?t=17008

ms00 · Post by **ms00** » 03 Dec 2005, 00:21

Owen, your car car is displaying very similar symptoms to mine mentioned in the above thread. Try disconnecting the vacuum pipe that is directly below the stepper motor. On mine this made the engine start and run normally-bizarrely creating a vacuum leak makes the engine run. Obviously this is OK in the garage but isn't suitable on the road. If you get anywhere with this seemingly quite common problem shout eureka and post a reply to me at the above thread.

micitroen · Post by **micitroen** » 03 Dec 2005, 01:02

One thing I've seen done in the past where there is a suspected vacuum leak or some other kind of inaccuracy is; with the engine running, to spray WD 40 or something like this into the area where you think the leak etc. is. If there is a vacuum leak ie a sucking.....then the revs will rise with the addition of the WD 40 and then fall back again. Worth a try if you have a suspicion re the inlet manifold also......same M.O and if its leaking the revs will rise just the same.

Owen101 · Post by **Owen101** » 11 Jan 2006, 10:06

whats causing it to cut out when cold?

First things first, should I immediately replace the engine temp sensor?

Sl4yer · Post by **Sl4yer** » 11 Jan 2006, 13:45

Owen101 wrote:whats causing it to cut out when cold?

A knackered stepper motor will do exactly that. Had the problem on my old 1.4i. Take it to a garage with diagnostic equipment - they should be able to tell if its broken or not.

Does the 2.0i use a Bosch system or Magnetti Marelli?

James

Owen101 · Post by **Owen101** » 04 May 2007, 17:30

Might be of help to someone else. Problems were solved by replacing the water temperature sensor, map sensor, lambda (oxygen) sensor, stepper motor and removed and thoroughly cleaned the inlet housing.

Also, I was getting petrol fumes in the car with the windows or sunroof down. This was fixed by replacing the fuel filter.

Thanks,

French Car Forum

Stepper motor, engine temp sensor or throttle sensor

Stepper motor, engine temp sensor or throttle sensor

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