engine dies under power when cold

[da dude]

ok, i have a 2001 (51 plate) mini one, it has a k&n induction kit fitted, but thats irrelevant, on cold startup, that is after at least 8 hours on a winters day and over night on a mild day, if i ask for any power from the engine at all within the first 2 mins of operation the engine drops off, not stalls. if it is very cold, and i ask too much of it it also gives a little backfire, this is a major pain as i live on a hill and have to drive up the hill to get out the road (there is a river at the bottom). i've changed the plugs and leads (kept standard) but it is exactly the same. i really think it is a spark issue but don't really want to fork out for a new coil pack unless i have to. i'm wondering if anyone else has had this problem and how they resolved it. It is the same if i run it on the higher octane fuels and if i have the standard intake fitted. if i rev the plums off it (which obviously is a bad idea on a cold engine) it doesn't die, as it is fine free, no load, revving.

Also, anyone know what the usual oil consumption is, its done just under 70k miles.

[da dude]

oh yeah, and there are no warning lights.

[M111 CGC]

I'd suggest there is a problem with a coolant temperature sensor on the engine that tells the ECU when the engine is warm and consequently controls the fuel mapping - like a manual choke on an old carburettor'd car. If the engine ECU thinks the engine is already warm and adjusts the fueling accordingly then it could account for the poor running and lack of power.

I guess the car is fine when properly warmed up?

Chris

[da dude]

Quote: Originally Posted by M111 CGC (original)

I'd suggest there is a problem with a coolant temperature sensor on the engine that tells the ECU when the engine is warm and consequently controls the fuel mapping - like a manual choke on an old carburettor'd car. If the engine ECU thinks the engine is already warm and adjusts the fueling accordingly then it could account for the poor running and lack of power.

I guess the car is fine when properly warmed up?

Chris

yeah, its actually perfectly ok after less than 5 minutes of driving. i just read a post on another fault thaat suggested the battery, this actually makes sense..... if the ecu is as sensative as he suggests. The battery is, as tested in about december, after being stood for about 10 hours, only about 30 to 50 amps down if memory serves me right, plus sometimes it cranks a bit slower, again, potential battery, its the original battery so its at least 7 years old, i think a new one is in store

[iain cooper]

sounds as if you are getting too much cold air into the engine on warm up..............could be the k&n induction kit ? has it been recently fitted and why do you say it's irrelevant ?

[davidscott]

This sounds like a variation of the earlier 'Stalling when cold' topic which none of us seem to have been able to resolve.

I have changed the plugs, had the sensors and the battery checked and had the car generally looked over -once uselessly by my dealer and secondly far more efficiently by an Indie on the south coast.

I have the K&N filter but for 3 winters now so I would not suspect it at all. The iridium plugs were 'hot' ones and replacing those with JCW plugs has improved things but it still wants to stall.

MINIMANIAUK suggested replacing relatively inexpensive items so I am going to try that asap. I will edit this post when I have checked what it was.

ETA: Replace these items in the order shown - all allegedly easy diy.
O2 sensor heater
coolant temperature sensor
map sensor

[Widgey]

I have an early build/model and experienced a similar "stumble" as you describe. An ECU remap (Bluefin etc...) should cure it and you'll get a Cooper+ power increase as a bonus

[davidscott]

Sorry to disappoint, but I had Bluefin anyway and switching between that and the original made no difference.

It's still well worth installing anyway.

[One_Time]

I've got the same thing on my wifes 52 plate One, I'm convinced it's a coil pack issue, it's the same feeling as when my Golf VR6's coil pack was on the way out...

I'm going to try and get hold of a replacement "known to be good" coil pack and see if it makes a difference.

I'll keep you updated..

[m_cooke999]

Yer i get the same problem mate however there is nothing wrong with your car... When cold on start up the ECU is automatically feeding more fuel into the engine, this is the choke... you cant expect the engine to be able to deliver power properly when cold anyway until it is warmed up and the choke is automatically switched off... all engines are the same mate.

[m_cooke999]

It only becomes a problem if your engine actually stalls when cold

[oldmots]

Quote: Originally Posted by M111 CGC (original)

I'd suggest there is a problem with a coolant temperature sensor on the engine that tells the ECU when the engine is warm and consequently controls the fuel mapping - like a manual choke on an old carburettor'd car. If the engine ECU thinks the engine is already warm and adjusts the fueling accordingly then it could account for the poor running and lack of power.

I guess the car is fine when properly warmed up?

Chris

I agree with Chris, I think the CTS is bad, youre getting a lean burn when cold, thus the backfiring. These parts are usually pretty cheap, it would cost more to scan the system to test it, easier to just buy one and put it in.
Brian Caro

[da dude]

Quote: Originally Posted by m_cooke999 (original)

Yer i get the same problem mate however there is nothing wrong with your car... When cold on start up the ECU is automatically feeding more fuel into the engine, this is the choke... you cant expect the engine to be able to deliver power properly when cold anyway until it is warmed up and the choke is automatically switched off... all engines are the same mate.

Not all engines are the same, and in all my years of mechanical experience, and driving many cars with manual choke, automatic choke and fuel injection this is far from normal. an engine will, when running rich, not stumble like this, unless it is running way too rich, which this isn't because it smells ok. but an engine running lean will so i also agree with the suggestion of temperature sensor, i have a basic obd scanner only used it once because my laptop failed, but when i briefly used it i noticed the temperature was unrealisticly high.

but all this is irrelevant now as the engine that was in it is now scrap, worn the crank out, so its got a new motor in it now. turns out these engines don't like to be even slightly low on oil, the level was never off the dipstick but had been a bit below the minimum, that and 83000 miles have killed it. oops.