Since all the car has ever had in it is premium fuel, I guess the thousands of us that have had the problem are just not shopping at the right gas stations.

 

A person with such vehicle credentials (your list of cars) must have felt
heart broken when your dealer told you crap like that, huh?

I did run into bad gas at Shell, but it did not affect idle.

 

Tell him to find you some good gas and prove it! MINI must think we are all a bunch of stupid schmucks. It's become typical of them though...

 

The lesson here is that if you make a car that is fun to drive and back it up with a cutesie marketing campaign, owners will put up with just about anything, including lousy engineering and lousy dealers.

 

1) I have tried different gas stations and have yet to find one that pumps "good gas"
2) Our other car uses gas at the same stations and have yet to find a tank of "bad gas"

I think all of us have already concluded that BMW/MINI/Siemens is incompetent.....
hmmm Boston is getting a whole bunch of Siemens subway cars. I wonder if I should stay away......

 

So my wife went in to pick it up and the tech told her "Make sure you only put premium in it and only buy from the national brands". So in other words, do what your've been doing and we just can't figure out what the problem is.

Its one thing to tell us that they just don't have a fix out. Its quite another to lie about the supposed cause.

This was the final repair attempt, next time it stalls I have the lemon law lawyer already set up to file a claim.

 

We've used Sams Club brand premium gas in our '02 MCS since we got it. A national brand, I guess. It sure doesn't have all the additives the other gas stations add. We originally had the cold start issue - fixed with SW update, then a rough idle after cold start - started right after another SW update. So what am I saying? It's their SOFTWARE!

 

In our '04 Cooper we use whatever premium fuel we find at the lowest price. Conoco, Costco, Shell, no-name - it has made no difference to our ride.

 

The brand of gas should make zero difference. That is a MINI cop-out.

 

If it is a national brand - I agree. But, if you go to one of the no-name deep discount stations I think you can end up with the cast offs from who knows what refinery. Or, if you go to a station that with low sales you might be getting your gas from a UST that has accumulated a lot of water condensation.

 

For what is worth, my '04 MCS runs smooth as silk since I switched over to Citgo 93 octane gas. Whenever I went back to Mobil/Exxon 93 gasoline, the car's idle was on the rough side specially with a cold engine. I was able to duplicate this time and time again by going back and forth between Citgo and Mobil fuels.

Citgo rocks and it is a dime cheaper per gallon than Mobil.

 

The gas manufacturer can and does make a difference in some markets. I have used Chevron in my MINI since new with no problems. But I had to put some 76 in it on a trip and the car ran like crap until I was able to get some more Chevron in it. Don't discount the brand and even the location of the gas purchased when having start up and rough idle problems. Sometimes just changing to a station across town can make a difference. I know it has with mine.

 

With the vast majority of these rough idle cases, the brand or location of purchase has made zero difference. I know, because I have been dealing with this issue for 12 months.
I have used Mobil, Citgo, Sunoco (even 100 octane), Exxon, Gulf, Bubba Joes gas stop, and many many more. All have produced the same crappy results.

I know various brands use other additives, but the fact remains that MINI has an issue with the idle. We know it. They know it. They haven't fixed it.

 

My contention was to simply state that there can be a difference in the gas purchased. I didn't say it will solve your problem, only that the suggestion by the mechanic was a valid one.

 

I had the problem only with Sunoco 94. It is because of the 10% Ethanol content. Quite a few in my club had a problem with it.
Got custom ECU flash for Sunoco94 and did not have a problem with it ever since.
So far so good.

Alex

 

Gas no matter who you buy it from comes from the same dead dinos and plants. Anyone who tells you its the gas in this day and age if full of...well there full of what you put in the gound for a million years to get gas...**** ok there full of ****.

If they told me that I would reply "so you really have no idea why it does this do you?" Dont let people walk on you and dont let them pass the buck.

Motor on.

 

I agree with Bisch...... I'm also in the Northeast. I only use the biggest of the name brands, and it makes no difference whatsoever. Current MINI software just isn't happy with Northeast summer gas.

 

This is a very serious problem. Has anyone seen this mentioned in the press? I wonder if it appeared in Car and Driver, Motortrend, Autoweek, Automobile, etc...if MINI USA would fix the S/W? Does someone want to inform them?

Clearly, I cannot buy the story about the gas. The S/W should adapt.

Regards, Mark

 

Whenever I have had a problem (cold start and bad smell on acceleration) with my S that they can't fix, the first thing they say is "try a different brand of gas". I would love to tell them " funny, BP/Amaco told me to try a different brand of car" :smile:

 

Hey all. Just had our 2005 MCS in for service yesterday (and she's still at the shop for today). It went in to have the CD player replaced which puked at about 250 miles. In addition, the other day I noticed that when we stopped at a gas station and were idling, it was idling rough. I blipped the throttle and it went away. Needless to say, I wanted the service tech. to check it out. I figured updated software might fix it.

So....

Jim (the lead MINI tech at Motorwerks MINI) put Molly on the diagnostic software and noticed that our "long term fuel compensation number" (not quite the correct term, I forget what is) was abnormally high. We were running about 7.6% while an '04 MCS he had looked at earlier in the day was running about 1.6%. He said that anything under 10% won't throw a CEL, but anything over 2.0% was a little high and indicated an issue. SO he started looking for vacuum leaks and found one at the mouth of the supercharger. To be safe, he decided to replace both the gasket and the intake pipe. The problem is that they had to order the intake pipe, so Molly had to stay overnight.

Basically the high percentage indicates that the computer was detecting a false lean condition and adding more fuel to compensate. This was causing the rough idle and worse gas mileage.

Those of you with this issue might want to have them look here. It seems to be an easy fix.

Hope this helps.

-Dave & Stacy

 

Please let us know if the new gaskets solve your problem. That would be great.

If anyone wants to know more about how this part of the fuel system works, read on. Some people have complained about my explanations in the past, so I'll warn you to stop reading right now if you don't like tech-talk.

The MINI's engine computer decides exactly how much fuel to inject all the time.

It looks at how much air is moving into the intake of the car with a few sensors. (I can get more detailed, but only if someone asks)

It then decides how much fuel should go into the intake so that it will just burn exactly right.

It them looks at a sensor in the exhaust called an Oxygen sensor to see how much of the fuel actually burned in the engine.

What is going on in your car is this:

The computer measures the amount of air coming in through the throttle body.
It decides to add some amount of fuel.
The engine burns the air/fuel mixture.
The computer measures the exhaust and sees, HEY!! The Oxygen sensor says I didn't add enought fuel. What??? I'll add a little bit more next time. Maybe 0.5% more.

The engine computer then does the whole think over again. Measure air coming in, add fues, measure exhaust going out.

What??? The Oxygen sensor still says I'm not adding enough fuel. I'll go to 0.75% more fuel.

It keeps doing this until in your car, it got to 7.5% more fuel than it should have needed to add based on the air coming in through the throttle body.

Why does an engine computer need to add more fuel? Well, it could be several things:

- If the fuel injector has junk building up on the end of the squirter, not as much fuel squirts out as the computer expects.

- If the fuel pump is producing a lower pressure than normal, not as much fuel squirts out as the computer expects.

- If air sneaks in some time after the place where the engine measures how much air is coming in, there is "extra" air, and the computer didn't add enough fuel. (This is what your mechanic thinks is going on in your car)

The computer keeps track of two numbers: Short-term fuel trim and long-term fuel trim.

I have no idea how long the short and long times are, but I'll guess that short-term trim is something in the 5-10 minute area, and long-term is in the one-to-several-hour area. (Maybe)

So, as things get boogered up, the long-term trim starts to get bigger and bigger. (or smaller and smaller if other things are changing)

When it hits either +10% or -10% (according to your mechanic), the "Check engine" light lights up, and the mechaninc reads out the error codes from the engine computer.

The mechanic might see one of these:
P2096 8342 Post Catalyst Fuel Trim System Too Lean (Bank 1)
P2097 8343 Post Catalyst Fuel Trim System Too Rich (Bank 1)

That code tells the mechanic what to look for: too much air; too little air; too much fuel or too little fuel.

So, why did your engine run rough if all this crazy stuff is going on?
Well, the oxygen sensor is fairly slow to respond. I'm not sure exactly how slow, but how about if it takes 10 seconds to respond.

When your car goes from medium-throttle with some sizeable air-leak at the supercharger, to idle, where the supercharger is bypassed, and not "sucking" so hard on the intake-side, I'm guessing that you stopped leaking air in through the gasket, but the engine computer was still thinking it needed to add 7.5% more fuel, and so at idle, there was too much fuel, and the engine ran rough.

When you blipped the throttle, you probably snapped the supercharger bypass valve closed and sucked in a little extra air through the leaky gasket and got the fuel mixture more normal.

It's an amazing thing that our engine/computer combination can keep things running so well for such a long time.

I hope this is was helpful and not annoying.

Maybe it can help you talk to your mechanic in a more informed way, and have a better motoring experience.

 

Trippy:

Thanks for the detailed reply. Some very excellent information that added to the info. we got from Jim. It's always nice to learn a little more about the MINI. I've been working on cars since I was 16 and probably know the Turbo I Dodge engines and trannys backwards and forwards. Now I get to relearn everything with the MINI (not to mention that the MINI's systems are WAY more complicated than a TI Dodge system).

It's neat to see how the new adaptive ECU's work. It is amazing how they can respond to keep us from destroying our engines. I really hope the new gasket and intake pipe solves the issue (I'm guessing it will).

What really impressed me was that rather than just fix the gasket and "see what happens", Jim wanted to replace the gasket AND intake pipe just to be on the safe side. Just shows the level of service and commitment to quality that Motorwerks has. We have been VERY impressed so far.

Thanks again,
Dave & Stacy

 

dont put am/pm gas into your car, not good stuff. chevron has okay but 76 and shell i would say has some of the best gases out there for 91 octane. i havent personally had any idling problem due to gas. i have heard of a slight ruff idle after a little while idling but nothing special. it happens to my every once and a while. hope it helps.

chris

dont put octane boosters in your car. injectors are not design on any car to have any fuel additives unless from mini/bmw. just a heads up