21 replies to this topic

[Carvell]

Hello,
I have a 2001 Mini Cooper sports pack 1.3i.
I have borrowed the car off my Dad for a little while.

In the morning when I first start the car the engine doesn't rev smoothly, the engine tone is up and down as the revs increase. To try to solve the problem the car had a full service. This didn't help so next the fuel filter was changed (this was still the original rover one and was filty inside) and the fuel tank flushed through and an engine cleaner put through. This improved the car for about two weeks.

The car is now back to juddering on first start in the morning. After 30 minutes of driving it continues to judder. If I then leave the car switched off for 10 minutes and then restart it runs sweet as a nut. However as it warms up again maybe 10 minutes later the judder returns. The juddering is enough to be audible, it sounds like the engine or something is rocking. It makes me rock in my seat as the revs drop. Speed and rev amount doesn't seem to make much of a difference. The only other thing that I notice but I'm not sure if its a mini thing is that when I go from no throttle to some throttle, its a very jerky feeling, no not progressive even though I'm not flooring it.

The only known problems with the car are the heater is stuck in the hot position and the cat is rattling. Both of these problems post date the juddering so I can't see them being linked.

Finally the car does seem to run a little hot. The gauge never gets above 1/3 so reads cool, it does move but not by much, however when driving around town when its a bit start stop the fan often kicks in then goes off.

Any advice would be appreciated
Thanks
Stuart

[charie t]

full service without changing the fuel filter?
it sounds like its misfiring, what colour are all the plugs?

[Carvell]

I will check the plugs in the morning and get back to you. Thanks

[Carvell]

Ok, I took the plugs out and they are all looking a little dark with a build up of carbon. They have not been on for more than a month and it hasn't covered many miles so they do not look too bad but definitely don't match the "normal" colour shown in the Haynes manual.

Back to my original post. I put the car had a full service, I have since realised that it in fact just had plugs, HT leads and oil. Since then it has had the fuel filter and a flush.

Thoughts?
Stuart

[Badboytunes]

You cat might have collapsed. This will make the car run like ****. Get it checked out ( i would remove it ) as when they collapse they can cause the car to judder and the sound can be similar to big end failure.......

[Carvell]

The cat is definitely rattling and does need replacing but I'm concerned that the cats issues have been caused by something earlier in the system and if I therefore a replacement cat will just end up going the same way? The fact that the cat was rattle free prior to the running issues leads me to think this.

[Badboytunes]

That will probably be a coinkidink pal.

to be honest, get a de-cat :)

[Carvell]

What's a coinkidlink?
It needs the cat for MOTs

[Carvell]

Upski

[bluedragon]

If you have blackened plugs, and/or a lot of soot in the exhaust inlet, and rattling cats - this could be a sign the engine is running very rich (overfuelled.) An excessively rich exhaust can actually cause that extra fuel to ignite and burn inside the catalytic converter, which in turn destroys the pellets and matrix in the cat and can lead to rattling noises from it.

One of the leading causes for this is a defective/worn out oxygen sensor. A rather longer shot is that you have a modded engine where the modder crimped the fuel pressure regulator to boost fuel pressure (in an attempt to add more fuel to support engine mods.) Other causes are more subtle to diagnose, but anyway if the engine is running rich, this can certainly lead to catalytic converter destruction.

[Carvell]

Thanks for the reply,
The engine is 100% standard, so no reasons for the rich running other than something being defective. Is there a way to test the oxygen sensor? ie unplug the sensor and if it is working correctly the engine will ...... If its not working then the engine will ......
Do you know what I mean?
Stuart

[Carvell]

Bump :)

[jamesmpi]

If you look above there is a pinned thread called testing the oxygen sensor.....

http://www.theminifo...89#entry1091089

Edited by jamesmpi, 12 November 2012 - 08:36 AM.

[Carvell]

Took a 2 hour drive down to AB garage in Queensferry. They cleared the fault codes and checked everything. Everything was working perfectly. Even with the dead cat they said it had the best emissions they've seen on an mpi. I asked them to keep it over night and see if it brought up anything different in the morning. Nothing. It's now running perfect, weird!!! Awesome service from AB garage. Will take it back in the future if the problem returns.

[jamesmpi]

good to hear its running well. another happy mpi owner ;)