Strange but True!!! Our 04 mini died on the road a while back. Diagnosed a bad fuel pump. Replaced that and filter. All fine. Drive it for a few days and it drives great BUT dies again while driving. Here's the weird part.
For some reason when we take off the gas cap, it will restart. Happened again today. Mechanic said we do have a small leak in an evap hose but it probably shouldn't cause it to die. Has anyone heard of these same strange
tales?
cheers
RKL

 

Dies how? More details are important to try to understand what is happening. I'm wondering is there is some kind of pressure issue in the tank, which could be alleviated when you remove the gas cap. Just spitballing.

 

Clogged PCV maybe? Something is building pressure that gets released with cap removal. Replacing the PCV is most likely your cheapest first option.

 

Right. So, while driving, just city driving, the engine just cuts off. I figure it's a fuel pressure thing, but it's not easy to diagnose and my mechanic is stumped. He's worked on minis for 35 years. cheers, R

 

Hey, thanks. That's the first time that's been suggested. We'll take a look. Cheers, R

 

Code ?

 

I guess I should get it diagnosed. I'll have that done. Cheers, RKL

 

To assure the gasoline vapors are caught by the carbon canister, the system pulls a vacuum and detects a leak, (like from a busted vacuum hose). If it cannot maintain a vacuum, it throws a code.

On the other hand, if it generates too much vacuum, it might not be able to draw fuel into the fuel pump and the engine dies of fuel starvation. When you open the fuel cap, you release the vacuum and it can pump again.

So when it dies, and you open the cap, is there a sucking sound or a pressure relief sound?

regards,
Peter

 

I can drive sometimes for a day or 2 and then sputtering and stalling then have to wait about an hour sometimes longer to start again. And sometimes it won't run even 10miles before sputtering and stalling and will start rote back up. I've changed plugs, wires, coil pack, fuel pump, cam sensor, position sensor, fuel cleaner, the f3 fuse which u found to be rhe cam fuse was blown. I changed the fuse and long behold it was great I thoigjt I fixed it. Nope ran about a day and same thing. It did blow the fuse and I replaced the fuse again and yet again sputtering then stall. As if its starving for fuel. This time the fuse did not blow. This time I took the gas cap off a drove home which was a 20 min drive and I made it. Unsure if it's the reason becaise the issue occurs so randomly. Any opinions lol I know its a long shot

 

The gas cap could be totally unrelated, could be just coincidence with time you take to wait before attempting a restart. Usually there's an evap or gas cap issue a code is present and yellow CEL...usually.

Fuse F3 (15A) is for: Pre and post cat O2 sensors, Camshaft position sensor, fuel tank ventilation valve solenoid, relay K19 control power.

Now since you have inadvertently connected this anomoly with the fuel tank, I would be inclined to change this part first. The Tank Vent Valve Breather Valve...MINI Part no . 13907572086 Engine compartment passenger side. https://www.oembmwminidiscountparts....ve-13907572086

 

I had an ‘81 Honda that was acting the same way, except for the blown fuse, and I also tried many of the things you did with no luck.

After a bunch of time, parts, and money, I decided to go to dealer and talk directly to a mechanic in the shop who told me there was a good chance it was a problem with the exhaust. Turns out the muffler was clogged and slowly built up back pressure like a clogged drain until the engine couldn’t breathe anymore and died. Sitting on the side of the road allowed to gasses to dissipate and let the car start and run until they built up again. How long I waited and how hard the engine was working determined how long it would run which originally made the problem hard to diagnose due to the randomness of the problem.

I would think the computer, sensors, and codes in a modern car would help diagnose the problem, especially if it was a problem with a clogged cat. Besides buying new parts that might not solve the problem, maybe someone here knows how the exhaust can be checked. Or, do you know anyone locally that might have a spare exhaust to try, or a junkyard that you can pick up something for cheap?

On the other hand, it might be an excuse to upgrade the exhaust and possibly solve the problem.