05 Convertable, 150K miles. Live in southern Nevada near Las Vegas.

First 100+ day of the year. Was driving around LV when all of a sudden engine started loosing power like it was fuel starved. Backed off throttle and engine picked up again. After about an hour of this - including stalling in a couple of intersections dropped it off at the dealer.

In the morning they could not reproduce the problem (of course) but did recommend replacing O2 sensors, plugs, wires, and fuel system cleaning. That's way beyond my check book so I decided to limp it home - 120 miles. Left town early and car ran fine for first hour. Then, as temps got up over 100 it started cutting out until at the end of the trip it was doing it every couple of minutes. Let car sit overnight and all day yesterday - drove it last night and it ran like a top.

The only diagnostic code in the computer is 0171 - bank 1 lean. No SES light on or other fault codes. I'm going to replace the upstream O2 sensor but I don't really have a lot of faith that doing so is going to solve the problem.

Thoughts?

 

Well - it weren't the O2 sensor. Ran back in to LV yesterday - about 110 degrees - car ran like a top all the way to town - about 2 hours. As soon as I started street driving car started acting up again - this time even worse with the stalling, cutting out, etc. Did see some periodic SES lights and the DSC light came on and stayed. Finally got where I was going and let car sit overnight. Drove home today - no warning lights and car ran just fine.

HELP!!!!!!!!!!!!

 

Sounds like fuel filter, or crap in the gas tank to me.

Think of it this way: you lose power when you're revving the engine around the RPM range (heavy fuel draw), so something's limiting fuel flow under high pressure; then you're on the highway at relatively low RPM and things are flowing fine when fuel needs are low. Something's getting clogged when the fuel pump starts really sucking (or pushing) gas.

 

I have an audi that was doing that when it got over 80 (doesn't get over 100 much here) until it finally cut out all together- fuel pump was burned up and couldn't keep pressure. Perhaps with sufficient cooling (cold gas) it runs fine, but then when the tank warms up it cant hold its own?

 

My thoughts, yes it could be fuel filter or pump related but it's actually not that likely on an '05 (again yes it's possible)

More likely on an '05 you have a map sensor getting ready to go out they have been known to gradually fail and the extra heat could be causing it to read out of the set range.

That being said the VERY FIRST thing I would do (assuming you don't have a tune) is go to the dealer and have them clear your adaptations, it could be something as simple as an adaptation that's stuck in the ECU that just doesn't agree with the extra heat.
(Besides it's cheaper than just changing parts and is something that should be taken off the table up front as far as causes.)

 

First - thanks to all for the suggestions

OK - let me take this in reverse order - and pardon my ignorance but what are "adaptations"? Far as I know this car is pure stock so not sure where you're headed with this.

I've felt from the beginning like this is a fuel starvation issue - just the way it acts up says "ain't gettin' enough fuel". Actually asked the dealer if there was a fuel filter to replace and was told it's more of a screen than a filter and it's on the pump in the tank. Might be the issue but.....

The MAP sensor was suggested to me a couple of days ago - was also told it could be cleaned and not have to be replaced.

Made a trip to Reno and back last two days - left early AM so didn't see 100+ temps until Virginia City and car started to act up on the climb up into town - again acting like a fueling issue - wondering if what netman86 suggested about fuel pump going out could be the cause - tank was down around 1/4. No problems comming home until tank got down around 1/2 and temp outside about 105 then bingo - cranky car. Actually parked in the shade for about 1/2 hour to make last 40 miles home - car ran fine for 20 minutes then 20 minutes cranky - tank level around 1/3.

Also - finally have a solid SES light so will have to find someone w/a code reader to see what the box has to say.

Again - thanks,
Mike

 

I am having the same problems with my 05 mcs, it started happening last summer, but only after 2 or more hours of driving. If you find a solution let me know.

I was at the mechanic this morining and had them clear the adaptations, I will let you know how it goes. I should know within the next couple days. I asked them about the MAP Sensor, they told me that there would be fault codes and they weren't seeing any.

I have replaced the fuel filter several times and that didn't help. I did hear somewhere not to change the small Oring inside the pump because the replacement orings don't seal, not sure if this has anything to do with the problem though.

Good luck with this, it has been very frustrating to me.

 

Nice to know (well actually not nice for you) someone else is having issues.

I'm thinking fuel pump wear coupled with outside temp and fuel tank level is affecting the pump output pressure/volume. I've been watching my avg. gas mileage and it's actually getting a bit better - which says to me the rig is running lean.

Drove to Las Vegas and back early this AM - OAT never above 95 - you'd never know the car was sick. When I got back into town stopped for the mail and let car idle - when I hit the road for the house the car immediately stumbled but just once and then smoothed out. Since I've also just turned 150K miles and don't have much choice in fuel vendors here I'm sure the fuel filter is part of the problem as well.

My SES light has gone off - thought that had to be reset by the dealer or a code reader?

What the blazes are "adaptations"?

 

Almost to the T of what my 05 justa went threw right before I traded it. I commute about 45 mins to work daily. And this summer has been hotter than normal. My mini ran like a Top while it was cold or cool but when it got hotter I could feel it losing compression when i got in to the town i work in. It esclated to this stalling or death idle while waiting at stop lights. I to took mine in to the dealer they said same thing Air/o2/fuel system. Next week it started giving me the SES light and I took it to the dealer and got the exact same code as you also my ses light came on before the stalls and turned off after i restarted the mini.... Next couple of weeks it was cooler and ran fine. I traded my Mini for a 11' MCS and 2 weeks after I traded it the dealer calls me talking about lemon laws and wants me to pay 2000 Euros for a new engine because it broke down on the way to the main dealer pick up. It now has no compression in 2 cylinders... I told the dealer that the ink was dry on my contract "car sold as is" and if something was wrong when they accepted it, then its their own dumb fault for not finding it the 3-4 times the mini was getting inspected before i traded it in.

Good luck and hopefully yours isn't going the way mine went.

 

adaptations should be your car learning your driving style. Aggressive vs Laid back for fuel eco reasons.

Might be wrong but in Jeeps the ECM/ECU remembers your first 100-200 gear shifts and claims those values IE clutch depression/RPM/and all the gizmos and gadgets involved with making the vehicle go forward and tells the ECM/ECU thats normal driving..... So if you bought the car used it still thinks either speed racer or Ms. daisy is driving not you which could cause your car to go in to a lean or heavy mode... tho tempture should have nothing to do with this I have seen crazier things fix minis..... Wiper grounding. The simple reset on a jeep was to disconnect the battery and "bleed the capasitors" by touching the negative and positive cable hook ups together..... But i wouldn't suggest that at all as sparks fly all over the place. I did it with my jeep by disconnecting the battery and shorting out the interior light to a ground and left it like that for 2 hours. Some people swear it will help your car get its pep back others say your chasing shadows. I thought it helped my jeep get some of it umph back.

But any where that can read your codes should beable to reset the adaptations.

 

So the adaptations were cleared, and Check engine light went off for a couple days. Didn't get a whole lot of driving in though, and the car ran fine. I scheduled time with the mechanic on my way home from work (1.5 hr commute) and just as usual started acting up again. They hooked the computer to it, and they told me it has to be the pump. What they found was that it was running lean and flooding to make up when it wasn't pumping causing it to loose power and bogg down. You can smell the flooding of the engine in the shop, never really noticed it before. I have not been able to get it in for replacement, but I will let you know after I get it done if anything has changed or if it fixed the problem.

 

Okay,
So today my thinking has changed a bit on the problem. Replaced the fuel filter last week - boy, what fun that was :(. Would've done the fuel pump at the same time but UPS managed to loose it in transit. After filter replacement (which of course was black as night, etc.,etc.) car seems livelier but the problem has not gone away. I didn't expect the solution to be that simple which is why I ordered a new pump as the only code I had was "lean". I think that the "lean" code threw me off - today, driving home the sudden slowing then picking back up was really bad and so I put the display on instant consumption. I'm getting readings that are changing from 31 mpg to 18 mpg then back up everytime she slows down - and today it was about every two minutes. The weird part about it is the timing - car has to run, with temps above 90, for about 30 minutes before the problem starts to occur. I do have a SES light now but no access to a reader before next week.
Thoughts anyone?

PS. Also replaced the T-stat - got to thank Bavarian Motors Don'tworks for having to disassemble half the engine bay to do that job :((

Mike

 

Well the issue is finally fixed. I got the fuel pump replaced and I have gone a week of hard driving, 90+ weather. I did all the same trouble shooting you did, a lot of the same thoughts. I changed the fuel filter several times and had the black fuel every time. I can say with confidence you probably have the same issue. The fuel pump is about $300 through the dealer, I couldn't find it any place online.

FYI my 2005 mcs has 225k and been driven hard. The guy at the shop said he hasn't seen a Mini with a fuel pump problem but he has seen porsche and apparently they use the same kind of pump. He said I got a lot of miles out of it, not comforting but oh well.

Hope this helps, and keeps you from spending more unnecessary money.

Ed

 

Well, it's been an interesting couple of weeks. UPS all of a sudden couldn't find my house so had to wait an extra 7 days to get the fuel pump. In the mean time problem has litterally played hid'n'seek w/ me - drove all the way to Vegas and back w/ no issues but then coming home a couple of days ago from work car died and wouldn't start. Lucky for me a short distance from the house so I went home a got some fuel - gas gage said 1/4 tank but car acted like it was "empty" - did I screw up the fuel sensor when I did the filter - don't think so but we'll see. Anyhow - put 3 gallons in the tank and the beast fired right up - was it empty or did letting it sit for 1/2 hour do the trick?
Got new pump yesterday and installed this morning - much easier job than the filter - and interestingly enough the new gasket was stamped "diesel only" - box unopened from BMW Group.
Have driven it a few miles - seems peppier but we'll see. If this doesn't fix the problem then it's time to do the FPR.
Took the old pump apart - kind of a clever piece of engineering - all the recirc line, screen limp home port, etc. I think the pump bearing are shot - pump was difficult to turn and noted that several of the impeller vanes were broken off.
Mike

 

Had this exact problem, twice, driving from FL to GA @ 7hrs @ Hwy speeds in 95+ temps in our '03 Cooper.
First time was last year, odo @ 145K, original pump. "Bad fuel sensor" code and "lean" codes. Fuel pump replaced, $300 for pump, $300 for diagnostics/replacement labor. Problem seemed solved.
Last week, approx 1yr to the day, same trip, odo @ 165K, same symptoms, same diagnostics. Fuel pump was warranted, so only cost $300 for diag/labor this time!
Mechanic assured me the second pump failing was a fluke, and I shouldn't have any more pump troubles. They should last the 7+ yrs like the first one, minimum.
It seems heat is a contributing factor, and I worry that something else has worn or gone partially bad and is killing the fuel pump. Something electrical like a relay or sensor?
If I find out anything further, I will post it.
Jack

 

Well first day of hot w/ new pump and car drove great. I noticed when I put the new pump in that there is a 1/4" line that clips into the top of the pump casing - is some kind of bypass or return line that probably helps keep the pump cool. When I took the old pump out that line wasn't clipped in where it was suppossed to be - I may have knocked it off when I was taking the pump out or it may have come out on its own. If it came out on its own that might explain why the problem generally only happened to me w/ low fuel tank level on very hot days - pump overheating.

Mike

 

OK, it's fixed - week or so of nice hot weather - 115+ and car has not made a hiccup since I replaced the pump regardless of fuel level. Replacing pump was way easier than servicing the filter - only took about 30 minutes. And, interestingly enough - the new gasket for the tank access was marked "Diesel Only" - just like the gaskets folks have been getting in the fuel filter kits.

Did a post-mortem on the pump. The whole assembly is kinda cool with provisions for limp home fuel flow if the suction screen gets clogged, etc. But at the same time it might be too complicated. Anyway - when I had the actual pump out found that 4 of 5 vanes on the impeller were broken and it rattles when shaken - pumps should not do that.