I am still trying to find out why my '05 r53 cuts out completely whenever I go up a long mountain grade.


Symptoms:


car runs fine here unless under load for several minutes, such as going up a 5 mile mountain grade in the Rockies. Example Vail Pass heading east. Doing ok all the way from Grand Junction to Vail, but then the grade picks up. Taking it very easy (i.e. 50mph in 5th gear or even lower in 4th), I made it 95% up the pass, but then the engine just shut down. That means, no fire, instantly, no warning. No rough running, just dead as if the ignition was turned off. Tach shows revs dropping as the car slows, 2-4 seconds later the car bump starts and continues, but once this problem surfaces, the car will do it over and over again, slowing as the grade continues, forcing me to shift into lower gears to keep moving. So far the only way I have found to remedy this for a while is to pull over and let the car idle. It will idle fine. When I pull over and shut it down, then start and get going again, it will still cut out. I did that test only once, but it was quite obvious that parked in idle is better.


There are no codes, not in the ECU, no warning lights before or after. Coil, wires and plugs were replaced, no change. I can get to WOT fine, but then it'll just cut out faster. First time it did this was going up a grade with a lot of boost, but it will do this at low loads as well, just later up the mountains.


My latest guess is obviously fuel. But the 4 cylinder shutdown is not consistent with that theory, unless the ECU shuts down to protect the motor from a lean condition. Is that something the Mini ECU does?


Fuel filter? pump? It just feels like I have a certain amount of fuel available, but once the engine load is high and throttle is above 33% consistently (I was running Torque app monitoring what I was doing), it is only a matter of time before the motor will cut out.


Any other ideas? Car runs like stink here in the flat states, and it will be very difficult to test any remedy here unless I break spead limits massively for 5-10 minutes at high loads/throttle position/speed. Ordering new fuel filter to replace next (90k miles on original).

 

I have just had the same issues on my 03/2002 R50. I suspect in my case that the injector cleaner I used, plus running the tank low before a refuel contributed to it.


Driving home in traffic was tentative at best but corners or any gradient saw the same issues as you described.


With the rear seat removed all week, I did notice that the fuel pump at idle was changing pitch from high to low. After a week of running a full tank each day ( I drive 120km round trip to work) I noticed the symptoms have ceased and the fuel pump now runs at a constant pitch (when at idle). No engine codes but I feel that the injector cleaner may have loosened up some varnish build-up inside the tank and running the tank low also contributed. I cant comment on the fuel filter as mine is the older tin can style that is not serviceable. I am currently in the process of swapping the old style filter unit for the new serviceable style. That way I can monitor the fuel cleanliness at least in the future should it re occur.

 

Anybody ever look at the cat? If melted/partially blocked issues are usually seen at higher rpms/high load situations....
Been over that pass many times when I lived out that here.....
Sorry to hear you still have an issue...good luck.

 

wouldn't a bad cat be immediately noticeable, not just after a 10 minute grade? I can go flat out for a while if the car has been cruising on level roads, so much that I'd be hitting terminal velocity long before the first hiccup when on level roads around here.


Also, this is not directly rpm related. These things all happened around 2500-3200 rpm. It has more to do with how long you run under load, rather than how high you rev, although I am sure you get there faster at higher throttle positions.


I can put 150 zippy miles on the car in the hills here and it runs like a champ all day long. In fact, I just drove it 150 miles yesterday, and every opportunity I got, I put a good load on the car, lots of throttle. Nothing. Runs fine. I simply can't get it do to this here (good thing, I guess). It literally takes miles of strong grades to get it to cut out. On the other hand, unless I can find a clear answer, I will never go west of Denver in this car again.


Again, no engine codes. It is a major malfunction when your motor goes completely silent for 2-4 seconds (until the rolling wheels bump start it again, keep clutch down and it will roll to a stop until you turn the ignition off and on). All other electronics in the car are still working. It appears to me like a radical form of "limp mode" implemented to keep the engine from being damaged by low fuel pressure, but I figure somebody should know if such a mode exists in the stock ECU.

 

Oh, and I don't have a rear seat in the car. Don't really hear my fuel pump, or at least I can't hear any sound changing pitch back there.

 

Having the same issue here. Mine appears to be heat related. 05 MCS.

 

id check the fuel filter, injectors and your fuel rail

limp mode would cut power, not the whole engine.....

did you replace coils and pack with aftermarket or OEM?

 

This is not limp mode that is happening. The engine is shut off. No throttle response. The engine just goes dead. It is still showing RPMs, and the dash warning lights are not on. Most of the time, while coasting, the engine will refire. But if I clutch in, the engine may not catch, but I can turn the key and start the engine and keep going.

 

engine shuts off, but tach shows rpm's because crank position sensor is working and the electronics do not shut off.

Obviously it is not limp mode - I know that mode too well from my Toyota Tundra. This appears to me like some sort of engine protection mode where "reducing throttle" isn't enough to keep it from going ultra lean on heavy load, as that could cause instant terminal engine damage. I am guessing it is something the ECU is meant to do, because there are no codes. Or it is just how low fuel pressure manifests itself in the Mini?

Like it's either there, or not there. No in-between. If it was just running out of gas, wouldn't there be a moment or so of rough running? The engine runs 100% fine at full song, and then when the problem occurs it's like somebody pulls the cord from the vacuum cleaner, and then 3 seconds later plugs it back in and everything is fine, for about 5 seconds, and then again, and again.

On a typical uphill grade, I'd experience the problem like this - dashes is running fine, x is engine is off:

-----------------x---x--x--x-x-x until I stop because I am out of lower gears to keep it going. Once I let it idle I can go back but if I go as fast as before and the mountain grade is long enough, it will repeat the process.

 

the rear o2 sensor should fire off a code if the engine was running lean, have you checked your plugs recently? they could be technically misfiring if worn out enough but not igniting, plus the engine shouldnt be spinning long(a second maybe) if there is truly no power

 

Plugs were fine when replaced in California. They are still fine (and brand new now).

There is no misfire. The engine runs 100% perfect when it is running, and it is DEAD DEAD DEAD when not running, There is no in between. No misfire, nothing is off when it is running. When it is not running it is dead for at least 2 seconds, probably more like 4 seconds, before it will refire by getting bump started if you stay in gear.

Coil was Mini original, replaced with a Bosch (I think) meant for Subaru and similar cars. Needed different mounting bolts. Replaced wires (which were crappy Alta) with Bosch. But like stated earlier, nothing has really changed after replacing plugs, coil and wires.