33 replies to this topic

[shedonwheels]

Hi all, had my 99 mpi for a month now, its my first mini and I know zilch about engines sorry....

First thing I'm concerned with is when I first bought it and drove the 160 mile trip home, when I got home my dad looked over it and he mentioned that it may be 'running a bit rich' as the exhaust end was blackened and he said it should be white after the trip. No idea what he meant by 'running a bit rich'.

Next problem has happened a few times, quite often early in the morning on my drive to work. I will have driven for about 2miles at 30-40mph with a couple of roundabouts, I come to stop at a traffic light and take my foot off the accelerator and the engine remains revving very high at about 2300 plus revs. Then I drive off again and come to another stop and it doesnt do it. Then I drive off again and come to another stop and the revs stick high again etc etc. Theres no pattern in when they stay high? I can drive very calmly keeping the revs low and when I come to a stop they are high, or I can be driving a bit heavy footed and come to a stop and the revs are nice and low and calm? I've tried depressing the clutch but nothing effects the revs. I'v even tried putting my toe under the accelerator pedal and pushing it up but it already is completely up. Boyfriend said maybe 'the accelerator is sticking'.

Lastly only noticed last night when got out of car and it was sat running but it sounds a bit funny, like its not 'purring' constantly. It was almost slightly chugging as if it was going to stall but not quite that bad. Boyfriend said it sounds like 'it's missing'. Missing what?! once again I have no idea what this means....

Oh and also when I fill him up the gauge never ever reads as full. I think this is a common problem and doubt its connected but thought better mention it.

Can anyone help shed any light? Are these things connected? Is the revs sticking high a serious thing?

[Sprocket]

Firstly we are dealing with a car that has Electronic fuel injection, a catalytic converter, and unleaded fuel, so the colour of the tailpipe means nothing

Your high idle speeds, are a common symptom of either a sticky throttle cable, sticking stepper motor, or a cracked throttle body. Easy ones to fix are the throttle cable and the stepper motor. Its easier to replace a sticking throttle cable, than try and lubricate it, that will only make it worse at a later date. The stepper motor can be removed from the inlet manifold and cleaned, it may need reseting within the ECU.

The plastic throttle boddies sometimes crack and distort causing the throttle to stick, treat this as the last resort problem, investigate the others before hand.

The way the EFi works, is by feed back from the Lambda (oxygen) sensor. This feed back alows the fueling to control around a mid point. The EFi will control the fueling to go rich, the sensor will return a voltage signal to say rich, the EFi then controls the fueling to go lean and the lambda sensor will return a voltage signal to say lean, the the EFi will then control the fueling to go rich, so on and so on. Its at the lean point that the engine sounds as though its stumbling and about to missfire.

If the Lambda sensor is on its way out, this stumble, may be more noticable.

If you are in doubt, have a diagnostic test done on the engine, whereby all sensors are checked via a hand held diagnostic service tool, that looks at the readings within the ECU.

Not knowing exactly how seveare these symptoms are, I can only speculate as above

Hope that helps

[shedonwheels]

Thanks for the reply.

Just been for another drive, it was terrible. I've now realised it does have something to do with my clutch use.

When I come up to a junction I ease off the accelerator and allow the mini to slow a little then depress the clutch before breaking if necessary. I've experimented and if I depress the clutch too early ie before i've slowed down enough, when I then lift off the clutch again after changing down to say second and pull away the high revs start like mad.

I just drove for 15 mins and after one junction there is a tight road with a 20mph limit and lots of stopping and starting to give way to oncoming traffic. The high revs started as I pulled away and were at 3000 at about 15mph! It sounds so stupidly loud! I had to pull over, switch ignition off then on again and drive off very gingerly again.

After lots more junctions I've got my clutch usage down to last minute, after breaking so I'm down to a max 10mph. Trouble is now my mini is almost bunny hopping up the road! Its as if it needs the clutch to be depressed but yet if I do the revs go mad when I then accelerate again!

Is this just terrible driving? I'm sure I'm not using the clutch too much? Never had any probs before in any other car?

edit: forgot to add when driving along that 20mph road it felt like I had a manual choke pulled out fully so I took my foot totally off the gas and the car just drove itself along?! It just kept going which forced me to break and then the high revs started. aag

Edited by shedonwheels, 09 August 2008 - 06:33 PM.

[haz]

Thanks for the reply.

Just been for another drive, it was terrible. I've now realised it does have something to do with my clutch use.

When I come up to a junction I ease off the accelerator and allow the mini to slow a little then depress the clutch before breaking if necessary. I've experimented and if I depress the clutch too early ie before i've slowed down enough, when I then lift off the clutch again after changing down to say second and pull away the high revs start like mad.

I just drove for 15 mins and after one junction there is a tight road with a 20mph limit and lots of stopping and starting to give way to oncoming traffic. The high revs started as I pulled away and were at 3000 at about 15mph! It sounds so stupidly loud! I had to pull over, switch ignition off then on again and drive off very gingerly again.

After lots more junctions I've got my clutch usage down to last minute, after breaking so I'm down to a max 10mph. Trouble is now my mini is almost bunny hopping up the road! Its as if it needs the clutch to be depressed but yet if I do the revs go mad when I then accelerate again!

Is this just terrible driving? I'm sure I'm not using the clutch too much? Never had any probs before in any other car?

edit: forgot to add when driving along that 20mph road it felt like I had a manual choke pulled out fully so I took my foot totally off the gas and the car just drove itself along?! It just kept going which forced me to break and then the high revs started. aag

sounds like my fiesta!

i changed the idle air control valve on that because my revs were sticking, not sure if a mini has one of those but anyway, if you keep changing down the gears and into 2nd when you're coming to a stop in an effort to keep the revs down it wont put as much strain on the engine - as you had described it bunnyhopping down the road! Thought that might help u for now, sorry i know nothing about injection mini engines to help propperly lol

[Rob.Finney]

I'd lift your bonnet and have a look at your throttle cable, mine got dislodged and i had something similar happen, although it was a once off and not continuous...

[shedonwheels]

Well had a friend drive the mini today and have a look under the bonnet. I can eliminate my driving as a factor because the high revs happened when he drove the mini too
The throttle cable is fine, he thinks it is more likely to be a problem with the stepper motor. Will hopefully get it looked at properly in the garage on tuesday.
He said it isnt even idling properly, it starts at about 1100 and never really settles down to the proper point.

He also said it isn't missing although he replaced the spark plugs for me and this did make things sound a little healthier.

He did say it looked like it was running rich due to the colour of the exhaust and he thought maybe there was a problem with the ecu ie one of the sensors (lamda?)

Can anyone explain how the ecu can be fixed, can any garage look at it/diagnose problems? Is this expensive. I have a three month warranty on this mini and want to get things at least diagnosed before the time is up at the end of september.

[minicooper1.3i]

If you've got a warranty on the motor, why are you playing with it?

Take it back to the dealership and say 'get it fixed and gimme a courtesy car in the meantime'

I bought a second hand scenic from a garage a few years ago and that came with a 3 month warranty. 2 months and 2 weeks later, it blew a water pipe and dumped all the coolant on the road. Got the AA to take me home and the garage came out with a flat bed, took it away and brought it back next day all fixed!

Sorted!

In answer to your question though, you'll have to take the entire car to a garage to get it plugged in to a diagnostic machine. Dunno where abouts you are, but DC Mini's in Potters Bar (next door to Mini Spares) have one and they seem pretty good. That should test your ECU and all the sensors. Dunno about costs but I doubt it'll more than a few hours at garage rates.

I doubt it's your ECU to be honest. They're usually pretty tough. Sensors are much more likely to fail than the ECU.

[shedonwheels]

Sorry that was me as a girl writing things as a girl would. I think my friend knows it's not the ecu and is really one of the sensors. I was just being dum. Should be finding out more tonight. Would love to take it straight back to the dealer but they are a three hour drive away!!! When we got the warranty written out it only covers certain things so until we know what it is thats wrong I'm not even sure I'm covered. The dealer also said, as we were so far away, we could get work done at home and send him the bill as long as we cleared the quote with him first......
We'll see.....

[shedonwheels]

Hoorah!

Hes fixed (for now).

So we took the stepper motor out, checked it cleaned it all and flushed everything through with redstar(sp?). Also checked throttle cable again. Still the same.

Took him to get a diagnostic test today. Plugged it in and we had two fault code readings- one for coolant temp sensor, one was ambient air temp.
The only problem I'd mentioned was the high revs, but the man at the test centre asked whether the mini sounded like it was missing after a long drive, and said it was prob running a bit rich. Which were all three of my problems-so they were linked after all....
He said that the coolant temp sensor was prob detecting that it was too cold and so was engaging the choke all the time-this is exactly what it was like to drive, like I had a manual choke pulled out all the way all the time!

The man cleared the codes and, wahey!! no more high sticking revs. He also did an emissions test which was passed.

And the best bit....he didnt even charge me the £25 for the test. Fellas you all need to grow your hair and die it blond and smile a lot and laugh at all the mechanics terrible amusing jokes. It worked for me!

[shedonwheels]

Uhoh

Back to square one, the probs are all back, came back after a fairly long run-out this eve.

Will be taking the mini back to the garage and I guess we will be getting the coolant temp sensor checked and repaired or replaced and anything else that comes up. So cross, it was so nice to be able to drive with no worrying about the revs everytime I change gear/slow down. And to know that my petrol wasnt being used up for no reason. Ah well ho hum, I spoke to soon didnt I. Should've touched wood. Dam it.

[lotusk]

Shedon, I think I am correct in saying that just clearing the fault codes from the ECU does not cure the problem-it just resets everything which means that the car will run fine for the next couple of starts until it re-detects the same fault codes again...

To get her fixed properly you will need to investigate why those fault codes are being generated.. could be dodgy sensor, wiring, etc... You have found out which sensor is the problem already though, so getting her fixed should be easy

Uhoh

Back to square one, the probs are all back, came back after a fairly long run-out this eve.

Will be taking the mini back to the garage and I guess we will be getting the coolant temp sensor checked and repaired or replaced and anything else that comes up. So cross, it was so nice to be able to drive with no worrying about the revs everytime I change gear/slow down. And to know that my petrol wasnt being used up for no reason. Ah well ho hum, I spoke to soon didnt I. Should've touched wood. Dam it.

[elvisthepizzaman]

Quote: "My mechanic man couldn't find where the sensor was when he looked. "

I would be looking for another mechanic if he does not know where the coolant sensor is located on a mpi mini, the thing is brown and is sitting right above the alternator for all the world to see coming right out of the thermostat housing. Its so easy to get to ill bet you could change it out yourself in about 10 minutes.

I've attached a useful diagram:
Number 11 is the coolant sensor which is brown and number 8 is the intake air sensor which is greenish just below the air filter housing

Attached Files

•  SensorPositionsgood_full.jpg   122.89K   42 downloads

Edited by elvisthepizzaman, 15 September 2008 - 04:45 PM.

[shedonwheels]

Hey you two. Thanks for that diagram!

I kind of knew just clearing the fault code hadn't fixed the problem but I clung onto the hope that it had! Also thought the problem would come back straight away, not after two days. Naughty mini lulled me into a false sense of happiness then got me with some SERIOUS high revs at some traffic lights. Tsk.

Elvis, the mechanic had to use my Haynes Manual to try and find it but still couldn't!!! Hes a nice guy and did the test for free, just not used to minis.
I've now decided I'd better get to the local Rover Dealers and either get them to fix it or if it's as easy as it sounds, fix it myself.

If I fit the new sensor myself am I correct in thinking I'll still need somebody to clear the error code in order for the car to work again?

[lotusk]

Your mini sounds like quite a character

The fault code will remain stored in the ECU until its cleared, but once the coolant temp sensor returns a correct reading your mini should start working correctly again without it having to be cleared.

Hey you two. Thanks for that diagram!

I kind of knew just clearing the fault code hadn't fixed the problem but I clung onto the hope that it had! Also thought the problem would come back straight away, not after two days. Naughty mini lulled me into a false sense of happiness then got me with some SERIOUS high revs at some traffic lights. Tsk.

Elvis, the mechanic had to use my Haynes Manual to try and find it but still couldn't!!! Hes a nice guy and did the test for free, just not used to minis.
I've now decided I'd better get to the local Rover Dealers and either get them to fix it or if it's as easy as it sounds, fix it myself.

If I fit the new sensor myself am I correct in thinking I'll still need somebody to clear the error code in order for the car to work again?

[shedonwheels]

I've just picked up a part from rover...the coolant temp sensor.

Can anybody give me a quick how to step by step. I'm guessing first step-disconnect battery.

Here is where it's going to go.....




And here is the part I picked up......




It seems fairly straightforward but is it? Sorry please humour me!