Not sure if there is a Throttle Position Sensor(or equivalent) on these cars, but that sounds like symptoms of a bad one...
Just another $.02
Kaveman

 

I don't think a throttle position sensor is sensitive to prolonged loads or elevation. There is never a problem with the throttle until the car is going up a significant grade.

 

I have an R50 and I believe it has the same fuel pump. My fuel pump had a bad crimp terminal where the wire from the outside connector connects to the pump motor itself. Was loose enough to make a open circuit and the pump motor would not run. I diagnosed it as a bad motor and ordered a new fuel pump; after I installed it I checked the motor terminals again and it had fixed itself! Thought it was a bad connection so I wiggled the blade connectors on the motor and one of them was loose.

Maybe yours is intermittent; mine was great until one morning when it made the open circuit. Pulling fuel pump is pretty easy- there are how-to's on here. Once you get it out check the internal connections to the motor.

Val

 

The R50 pump produces a bit lower pressure. It's a VDO white top pump while the R53 has a green top. If you want to confirm fuel distribution issue, there's a Schrader valve by the fuel injector rail. Remove the intercooler & hook in a pressure gauge. Turn key to position 2 to prime the pump. Pressure gauge should read 52+ psi for the r53, around 42psi for the R50. Anything less, it may be the pump or if you're lucky, it's justa cracked hose from the pump to filter. I had that issue. If so, make sure you replace w/ a Gates 30r10 submersible fuel hose. A non-submersible one will fail.
Hope you hunt down the issue.

 

This isn't the solution to your problem (at least not the main one), but if your engine temps are usually that high, your low speed fan is probably not working. As long as your high speed fan still comes on at 205, there isn't an immediate danger, but there will be cumulative damage to a number of parts from the excessive heat (alternator, ac compressor, etc). May be time for the resistor fix.

 

Did you ever get this resolved? I am having the same problem here in Tampa. My 05 MCS will coast down, no power, but still showing RPM, when it is hot. Most of the time the engine will refire, or if I put the clutch in and the engine dies, I can restart it once the tach reads zero.
It also happens when the car is idling and it is hot. Drove to a mechanic's house because it was stalling at speed. Got to his house, rough idle and stall.
We changed fuel pump relay, no change. looked for a vac leak..all good. The other odd thing that happens is that when the car is hot (after work, on the way home), it will stumble or shut down in aggressive right hand turns.
None of this happens on my morning drive to work when it is cool.

 

Never got it resolved. I cannot replicate the conditions my R53 does this where I live. My problem more or less had nothing to with heat, at least 9 out of 10 times, the engine was running cool, everything inside cool to the touch. I exclude that one hot highway run without load from my samples, as I never had a problem like that day again. It may be related, but another day we drove 250 miles through Nevada, 100 degrees, AC on, 7-75mph, up longer but not super steep grades and no issue. Then, same day, cooler higher mountains and steeper grade it cut out again, no AC, 80 degrees max, motor running at normal temps. No issues with right hand turns; almost sounds like a fuel pickup issue.

My car also never idled rough. But the coast down and then refire if in gear is the same as you describe, if I stay on the clutch, same thing, will not refire.

I replaced all ignition parts, no change. Getting new fuel filter delivered today. Still won't know if I fixed anything unless I drive 1000 miles to Denver had hit a long grade.

 

Hmm...my problem is exactly the same as yours, less the heat issue. On Friday, it was really hot in the afternoon. The car sat in the garage all day and was driven around in the late afternoon heat for about two hours with several stops. It started cutting out. No dash lights, no check engine, RPMs stayed consistent with engine speed, but the engine was definitely off. At speed, the engine will refire almost every time. But if I hit the clutch, and let the engine wind down it MAY stall...also the right turns have me confused. It will buck in the right turns, and if I clutch in, it may stall.
Fuel Pump, and filter were replaced maybe two months ago, when I first had problems which culminated in a no-start situation. Temp gauge shows normal operating temperature, the heat is ambient heat that makes a difference if this will happen or not.

 

how hard do you have to go? I monitored my engine with Torque on Android via bluetooth while all this was happening, and never was I running at less than 100% load on the engine and less than 40% throttle. If I did that around here on our flat roads, I'd have to go 100mph for several minutes to simulate a similar load.

My engine won't "wind down" when I hit the clutch - it's off. Done, no spark. 0rpm if I hit the clutch. If I stay in gear it is just like yours - it'll wind down on the tach as speed drops, eventually refires a few seconds later, being bump started more or less.

I described my symptoms over in the drivetrain forum in this thread in more detail after I limped my way back home across the mountains:

https://www.northamericanmotoring.co...ing-codes.html

Temperature was no issue with the majority of my engine stalls. Again, absolutely no rough idle, no issues when the thing has gas or whatever it is that is not there when it shuts down. When it shuts down, it just dies, no spark on any cylinder. The only way I can keep it going is to reduce load on the car, which in the mountains meant flashers on and drive behind ancient camper vans in 3rd gear at 30% throttle max, or about 25mph up the grade. Go faster, and a few miles and my car would cut out. Park it in idle for a few minutes and I am good to go for a few more miles at higher throttle positions. It all smells like fuel to me, except for that one hot start in Owens Valley after heat soaking the engine bay.

 

It happens during normal driving, it happened at 75 mph, it has happened at 45 or in stop and go traffic. On Friday, left the car idling on the driveway and it would try to stall, mostly catch itself, after an incredibly "lumpy" idle.
I have gotten really good at getting the engine re-fired on the fly by clutching in, and hitting the key. Last time I checked, last week? there are no codes. No SES light, no other warning lights. Sure does feel like a fuel delivery issue.

 

Symptoms are the same (cutting out), but it definitely doesn't happen under the same conditions. I have driven over 1500 miles since the last time it happened, and the last time was on the way up to Vail Pass in Colorado. I can drive here all day long, don't worry one bit about it happening. I can drive quite spirited, because I think my car "recovers" when you get off the throttle for a bit.

When it did happen, since it was always on steep long uphill grades (except that one time), the refire would be one gear lower each time. A few seconds, bang, motor back, then within a few more seconds it would do it again unless I kept slowing down more, and if I kept trying to keep going at the same speed, I'd find myself in 1st gear real fast. The only way for me to really keep going was to pull over and let it idle for a while. Pulling over and turning it off, then restarting and going back up the hill at load would have it cut out again within a few hundred yards.

It's like a certain reservoir of gas runs out and then needs to be replenished. When I drive around here, I never get to the point when that reservoir is depleted.

 

I initially thought it was something with the fuel tank, because it was primarily happening on right turns. And the tank was a bit low ... but then it started happening with a full, or nearly full tank of gas. So that seems like it can't be fuel starvation due to fuel sloshing around. I am now convinced it is heat related. But no clue on the cause.

 

Anyone found what is wrong with our cars? Mine has a similar issue, but it doesn't really happen until the car has been driven for 90 minutes or so, then if I take off from a stop I go for about 20 yards and then the engine cuts out. . . and once that starts happening it will cut out a few seconds after a moderate turn left or right or just on steady state flat road driving. . . complete cut out and then just comes back . . . no codes. . . no lights. . .

Really don't want to take it to the "stealership" for diagnostics. . .

 

I just got my car back from Mini of Wesley Chapel...they had it for about two weeks trying to diagnose the cutting out issue. Their solution was that the fuel supply to the pump was getting interrupted. In the trouble shooting process they basically replaced all of the internals in the fuel tank. Only charged me for the fuel pump replacement. Will need a few days driving in the Florida heat, but so far, so good.

 

My cutting out seems to happen with fuel low/half full/or almost full tank. Was your experience similar?

 

I was less convinced that it was fuel level related. Just heat. I had it happen about 90 miles into a tank of gas, and maybe even more than that. But it happened consistently when it was really hot outside. Never happened in the morning, regardless of fuel level.

 

Makes me think it was a fuel pump/filter issue. (all inside the tank)

Motor on!

 

Just ordered a used fuel pump (only 39,000 miles) and a filter from Way Motor Works. . . will see if that fixes things!

 

Could it be Vaporlock?

 

Hello there. Did you ever get to the root of the problem? I have a 2005 R52 and I'm having the same issues. When I drive it for an hour or so and it gets good and warm, it'll cut out under load. Complete loss of power for a couple of seconds then it picks back up. On one occasion, it was so bad the motor would not recover and would stall... Had to limp it home keeping the RPM's wrapped up. It doesn't give me any warning lights and no codes are stored. Had it in the dealer and they stated the only code stored was for an O2 sensor and they replaced but it made no difference. They stated it was likely my Magnaflow cat back and intake but the car did it before these mods were done. I went back to the stock air box for the hell of it and it hasn't made a difference. I'm curious if these similar issues have been resolved. It's a low mile well care for car... 41,000 miles. Any insight would be appreciated.

 

Never got to the bottom and I cannot replicate the conditions where I live (long mountain roads and continued load). Since last year, I replaced fuel pump and fuel filter, and by now pretty much everything else on that car (engine damper, new belt tensioner and idler pulley, plugs, coil, wires).

One detail that had me think it's fuel pressure related was the fact that when after it occurred I pulled over and let it idle for a couple of minutes, I had a good amount of range up the mountain before it would cut out again. If I powered it off and started again it would cut out much sooner. Just stopping for a brief moment would almost immediately have it cut out. It seems that the pump just couldn't keep up.

I never got an answer if low fuel pressure would cause these symptoms, but then there was nobody who had a better idea.

The fuel filter was dirty, but I have seen worse in photos of other people's Minis, and the pump clearly worked, but possibly not at full pressure.

Regarding the symptoms - if I did not keep the car in gear, it would just die. In gear, it would bump start itself after a second or two and then run, but if I continued to go up a steep grade at that point, trying to maintain or gain speed, it would immediately cut out again. The heat soak I think had nothing to do with it and just distracted from the fuel delivery issue. One time the car did it on Vail Pass, and I was able to pull over at the crest - opened the hood and the whole engine compartment was nice and cool.

My car never had any codes when this happened, so the O2 sensor is probably an independent issue, or the dealer was just trying to make a quick buck while he had you in the shop. I know my codes are caught fine my the OBD-2 scanner I was using at the time, because recently I had a P0300 random misfire (bad gas? Hasn't happened again), which it recorded just fine.

I am not sure if I ever resolved it, so I keep looking for possible fuel line issues. Today I am going to inspect the return line from the fuel pressure regulator (under the intercooler), because I am told it could be related to that misfire. And while there, I will check that regulator. If it's not too expensive, I'll probably order one and replace it this summer as well, although I just saw a fuel pressure test gauge on Amazon that's just $32 and has the proper Schrader valve on it. I'd actually like to have a permanent fuel pressure gauge in the car, because those would measure what matters when actually running under load, but those are expensive.

Thing is, I feel the problem will only be evident when the car has been run hard, which is not something you can do with the test tool connected. I was able to do hard pulls with the car without any issues if they were limited in time. Just the long uphill runs and continued sub 20mpg realtime fuel gauge numbers would lead to the cutout.


Good luck isolating the problem. please post here if you ever figure out definitively what caused this condition.

 

Thanks for posting. I'll keep you posted on what I find. Do you happen to have any mods on your car or is it stock?

 

intake and 15% pulley are the only engine mods.

 

One more thing that can interrupt fuel flow is the purge valve, which MINI/BMW calls "fuel tank breather valve". It's very easy to replace, worthwhile to try and eliminate it as a possible cause.

http://realoem.com/bmw/enUS/showpart...77#13907572086

It's actually a generic part used on many brands of cars and you can get it much cheaper than MINI's price (search the web for a part number cross reference).

 

hey, I know that part - its the first thing you have to remove when you are replacing the belt tensioner. I had this thing off the car many times this year without knowing what I was actually holding in my hands. Seen it for less than $50 so it is on my to do list for later this summer.