mg montego tick over

[calwing]

This is my second cry for help with this problem. My f reg. mg montego has a tick over of 2000 at times which then comes down to about 1200 but I cannot get it down any further and I cannot get it through the m.o.t.Sometimes when I start her up she revs up and down on her own without me touching the pedal!When I disconnect the tube that goes from the inlet manifold to the ignition e.c.u.the revs drop and when I put it back the revs rise again.I have swopped the ignition e.c.u.from another scrap car which did not have this problem and the same thing happened.I have cleaned the throttle housing and the stepper motor.The temp gauge does not work.Anyone with any other suggestions!!!!Mike

[E_T_V]

If the temperature gauge doesn't work the car will think it is cold all the time and apply the choke (meaning a high idle speed). Try a new sender and trace the wiring to make sure it is alright. Also give the multiplug on the ECU's a good wiggle to make sure they are seated correctly.

[Landcrab1800]

I used a local home tune company to check mine over. The hand held comp they have should show what problems there are. Cost me £50 for the privalage.

The cooling sensor does sound the culprit.

[E_T_V]

A new coolant temperature sender will cost you about a fiver so I'd fit one and see if that helps. Let us know how it goes.

[Jeff Turbo]

Could be the potentometer on the thottle housing. There are a couple of cogs in it and they might be sticking. I had this problem a few years ago. After cleaning it and putting little lub on it, it was fine.
Jeff

[E_T_V]

Does the Efi have a throttle pedal switch? If so could this be the problem? My best guess is the temp sensor though.

[Blair G]

This is my second cry for help with this problem. My f reg. mg montego has a tick over of 2000 at times which then comes down to about 1200 but I cannot get it down any further and I cannot get it through the m.o.t.Sometimes when I start her up she revs up and down on her own without me touching the pedal!When I disconnect the tube that goes from the inlet manifold to the ignition e.c.u.the revs drop and when I put it back the revs rise again.I have swopped the ignition e.c.u.from another scrap car which did not have this problem and the same thing happened.I have cleaned the throttle housing and the stepper motor.The temp gauge does not work.Anyone with any other suggestions!!!!Mike

ETV is right, I had the same problem and thought about replacing all the sensors untill Rover gave me A PRICE !!! I ran it or a while with it disconected which worked fine (exept on cold days-it needs to be reconected till it starts) then I fitted a superchip and K&N filter (I use it for raceing)and for some reason the temp gauge worked and I had no probs with the choke sticking on! Wierd, I know but we also done away with the A.I.S (air intake sensor). To date we have still not had any problems with it, temp gauge works and it still starts first time although it has been krypton tuned and on the dyno.

web: www.blairgmotorsport.co.uk

mail: blair@blairgmotorsport.co.uk

[Raúl]

Hello from Spain!

I have an Austin-Rover Montego 1.6 Clubman ('90)
I am his third owner.
My car has the same problem as Calwing´s one.
I read carefully the Haynes guide and I don´t find the problem.
Because a extrange reason the stepper motor doesn´t work fine. Perhaps due to a sensor as you mentioned above...
I don´t find the throttle pedal switch...Does the Clubman have a throttle pedal switch?

In Spain is very difficult to find this model and I have travelled about 5000 km whit the stepper motor plug disconnected and the symptom disappears. Of course, it takes 10-20 minutes to start the car on winter! It´s a pitty.

In my car the temp gauge works but the symptoms are the same.

I´m very interested in reading about your progress! :)

Thanks!

(sorry my poor english)

[E_T_V]

If the stepper motor is sticking it is most often due to the "o" rings inside it perishing/swelling/splitting. If you replace these with VITON replacements it may help a lot. If you search the forum for VITON you'll find what I'm on about. Don't get standard rubber replacements as these will swell and stick again (as they react with the newer types of petrol).

Hope this helps you.