Motor almost stalls

**Disco98** · 17th April 2009, 01:55 PM

Hi everybody,

Problem is when putting the car into gear the motor almost stalls then revs back to 750rpm almost stalls again then back up and sits at around 650. It also happens whenever I stop. However it drives fine no problems even idles fine in neutral or park at around 650 with no real fluctuation. If I increase the revs slightly to around 750 using the accelerator while at traffic lights the problem doesn’t occur. It started about 2 weeks ago intermittently and is increasing in frequency. The car had a service about 3 months ago and a tune up, vacuum advance unit, new leads, coil, distributor cap and rotor button fairly recently, have cleaned the stepper motor and MAF contacts today with no real noticeable difference. At time of tune up was told that MAF settings was reading a little higher than normal and could not be lowered any further, then told this shouldn’t pose much of a problem other than running a little richer and going through a little more fuel.

It is a 98 discovery 3.9 V8.

Any help would be greatly appreciated.

Cheers,

Dave

**PhilipA** · 17th April 2009, 02:03 PM

This is a characteristic of 14CUX and rover V8, and it is worse after a lot of short trips.
Mine recently started doing this so I chucked a bottle of injector cleaner in and it has helped.

Also at this time of year they change the petrol and the hot weather petrol can sometimes cause this in cooler weather. Just a new tank of fuel can sometimes fix it.

An Italian tune up helps also.
If you have done the above with no change then you have to start looking further.

Regards Philip A

**Boxer** · 17th April 2009, 02:12 PM

Also can help to pull out the stepper and clean the pintle as well as the seat and also give the throttle body a clean. That and make sure the brass bung in the TEE piece isn't blocked.

**Disco98** · 17th April 2009, 02:29 PM

Originally Posted by Boxer

Also can help to pull out the stepper and clean the pintle as well as the seat and also give the throttle body a clean. That and make sure the brass bung in the TEE piece isn't blocked.

What sealant do you use when installing the stepper motor?
Manual lists loctite 241, could only find permatex am not sure which one of the many to get.

**Boxer** · 17th April 2009, 02:44 PM

Originally Posted by Disco98

What sealant do you use when installing the stepper motor?
Manual lists loctite 241, could only find permatex am not sure which one of the many to get.

Umm, I've only ever just replaced the washer and I think I used a little bit of thread tape. Seems like a safe option

**Disco98** · 17th April 2009, 05:18 PM

Cleaned the stepper motor

The problem has not reoccurred since, car idles good in and out of gear moving or stationary.
Not perfect but heaps better.

Don’t know why probably just me but the auto transmission even seems to change smoother.

A little surprised tho, the stepper motor was cleaned when I got the service done and again when I got the tune up not that long ago.

Thanks for the help.

Dave

**discowhite** · 18th April 2009, 08:43 AM

stepper motors come under this code ''POS'' ive never had one that works properly...new or second hand

i just live with it now..

the best result i had was to remove the fiber washer and thread tape it. this pushes it further into the seat and changes the opperational length, (so its now working in a new spot on the shaft) this worked for over a year.

cheers phil

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