running problems

[bod]

hello every one hope someone can help me.Me and my wife have owned montego 2.0 contryman L reg for nearly 3 years . But the last 12 months the car engine runs all over the place when it gets to running temp . I have change so far both ecu fuel and ignition ht lead plug the whole exhaust sytem including cat because it blew .the whole problem started when the cat blew . i went to my main rover dealer but they could not help. oh the spark plug are pure white :banghead: :banghead: Help or any advice would be grateful

[Beaker]

Sounds like it is running to lean with white spark plugs.

Lindz

[G Force]

Hi there, spark plugs that are white in colour would usuually indicate that the air/fuel mixture is too weak, this can cause poor performance and rough running. As for the cause you need to supply a little more info, such as symptoms, carb or injection etc.

cheers gary

[bod]

Originally posted by G Force
Hi there, spark plugs that are white in colour would usuually indicate that the air/fuel mixture is too weak, this can cause poor performance and rough running. As for the cause you need to supply a little more info, such as symptoms, carb or injection etc.

cheers gary

our montego is fuel injection automatic. the car runs fine on choke but as soon as it comes off choke the tickover go all over the place and it keeps stalling all time when u stop say at road junction when in gear :banghead: :banghead: :D

[E_T_V]

On the choke the mixture is richened to make the car run ok. When it warms up the car leans out the mixture and this is causing the rough running. Are all the spark plugs the same colour, if only one or two are white it could be blocked injectors? If they are all white it may just need re-tuning (although I've not got a clue how to do that on a fuel injected car yet).

[MGTurbo]

Mixture not really adjustable, i'd be looking for air leaks, check vacuum hoses, manifold gaskets etc.

Gareth

[threelitre]

If you gat a cat in it, might it be that the lambda sensor has gone?
As this will regulate the amount of fuel injected.

Alexander

[bod]

Originally posted by threelitre
If you gat a cat in it, might it be that the lambda sensor has gone?
As this will regulate the amount of fuel injected.

Alexander


tried one off another car made no diffrence also replaced fuel ecu under dash

[E_T_V]

Maybe a longshot but what about the crank position sensor? Is their an airflow sensor on them too? If so it might be that.

[tony]

i would agree that it sounds like a air leak somewhere,maybe one or more of the rubber pipes are spliting near the end of them,.allso i would take out the crank position sensor and give it a clean ,they allways benifit from it

[MGTurbo]

Cleaning the CPS won't do anything to affect the mixture, it would cause an intermittant starting/misfiring problem or total failure, it can be checked with a multi-meter but not worth taking off IMO.

Gareth

[Landcrab1800]

Hasd same problem with my 2 ltr MG with MEMS control units.
I changed the throttle switch, this is hidden behing the throttle pedal just below where the cable attaches.

Also, my home tune man had an old electrical box that allowed him to set my CO. It is now running at 2.05 instead of 2.5.

He also told me that the vacuum pressure into the ECU is critical. This also controls the mixture.
The vacuum pipe goes from the inlet to a unit on the bulkhead and then to the black box.

Hope this helps

Gordon

[bod]

Originally posted by Landcrab1800
Hasd same problem with my 2 ltr MG with MEMS control units.
I changed the throttle switch, this is hidden behing the throttle pedal just below where the cable attaches.

Also, my home tune man had an old electrical box that allowed him to set my CO. It is now running at 2.05 instead of 2.5.

He also told me that the vacuum pressure into the ECU is critical. This also controls the mixture.
The vacuum pipe goes from the inlet to a unit on the bulkhead and then to the black box.

Hope this helps

Gordon

cheers i will try that
:) :) :) :)

[G Force]

If you still have problems you could try disconnecting and plug up the pipe at the fuel pressure regulator. this will have the affect of richening the fuel mixture on idle and light throttle, if this improves drivabillity and idle quality, you may have a problem with glazed injectors which would require cleaning or renewing:)

Regards Gary

[Landcrab1800]

bod,
forgot to mention that to chech the throttle switch disconnect it. It should idle high.

If you change any componant on the MEMS system it takes a while (200 miles on mine)for the system to settle properly

Have fun the switch means sitting in the seat upside down.

Gordon
:laugh: :laugh: