R53 starts.....then dies sometiems? Why?
 

I’ve started having an issue with my 03’ R53 over the last few weeks. It seems to only happen if the car has been sitting for more than a few hours…..I usually notice it in the mornings when I go to work, or at the end of the day when I leave work. It doesn’t do it all the time…maybe just once or twice a week.

When I start the car up, it runs rough for just a second or two.…and then dies. Then when I try it again.…it always fires right up without any issues and acts normal. About 3 months ago I put in a new fuel filter, plugs, wires, and the normal routine maintenance stuff….so I wouldn’t think it would be any of the simple stuff like that. The motor runs nice and strong…with no issues at all. The only issue is that every now and then right after it starts it wants to die on me.

No CEL’s, no other issues….Any ideas?

battery.

The battery isn't very old. Why would the battery cause the issue?

you have anything else hooked up to the battery? like an amp, capacitor, ect?
it just seems like the battery in these cars is a culprit 7/10 times for weird stuff.

how old is not very old?

No, nothing else hooked up to the battery. It's around 5 months old. If the battery was the issue, I would think I would have a slow cranking issue. It cranks up nice and fast...just dies as soon as it fires up. It will only do it one time...the second time you try it, it fires up just fine.

my guess is bad gas. try another company/gas station

Make sure the terminals are tight on the battery..

Since you said you changed your fuel filter I would check that the gaskets for the filter are sealing correctly. If these are loose you will lose prime in your fuel lines after the car has been sitting for a bit.

Check your fuel pressure thru the Schrader valve by the injector rail to rule out pump or in-tank hose leaks.

Mine does the exact same thing. When it sits for a while, it sometimes doesn't start the first try. I am positive it's not the battery. Second try, it fires right up like normal. I have tried turning the key and letting the car run it's course, until the dash lights turn off, and it doesn't make any difference. I have also tried giving the car gas when turning it on. I might give resetting the ECU a try.

Minsanity - I think the fuel pump is a good thing to rule out.

You wouldn't believe my journey....just had 22psi fuel pressure instead of 50+. Discovered the hose from pump to filter was split. Fuel was just circulating back to the tank.

How that split was pure mystery. Pump & filter were untouched from new. Had to swap in a submersible fuel hose. A Gates 30R10 should do.

TMAP Sensor failing?

The reason I say this is that mine just went out (thats the front one) and I think it had been going bad for a while. The car occasionally ran a little rough and started to get a little hard to start.

It can be tested if you know of a shop with a Launch tester (or similar) or maybe have a MINI dealer do a diagnostic test on it.

Thanks for all the info guys. I'm leaning towards a fuel issue also. The strange thing that I don't understand is that when you first turn the key on you can hear the fuel pump running to prime itself and pressurize the fuel line.....so even if there was an internal leak somewhere, it still should start after the system is primed. Right?

If it won't start on the first try.....what magical thing changes that makes it start right up on the second try and run like a top?

I guess I need to get a fuel pressure gauge and see how much pressure I'm getting out of the pump.

Mine just worsened gradually. First occured after I switched car off briefly & it took 2 attempts. Randomly, it started right up cold, at times after 5-6 key turns regardless of engine temp. Ruled out coolant temp sensor after swapping it w/o any improvement. Most of the time it ran well w/ random hesitation when pushing.
Hope you'd hunt it down.

Thanks for the info on the hose, I may have to check that out. That and fuel pressure are what I want to look into first. :thumbsup:

Do the fuel pressure check first. If pressure is good, pump & hoses should be fine. Pump extraction must be handled w/ detailed care to avoid gas spills & drips on the carpet.

On my 2006 R52, I had a startup and idle stalling problem that was resolved by replacing the fuel purge valve (MINI calls it a breather valve).

http://realoem.com/bmw/showparts.do?...=13&fg=15&hl=1 (item #1)

Thanks...if the fuel pressure checks out good, that will be the next thing I will have to try. :thumbsup:

Well, I did a little more trouble shooting today. I think it's definitely a fuel problem. It's happening more often now......any time the car sits for more than 3 hrs it seems to have the starting issue.

The one way I can get around the starting issue is if I turn the key on, wait until the fuel pump turns on and primes, turn the key off, and then turn it back on and allow it to prime again.....the it will fire up without any issues.

So....for some reason, it's almost like it's not pressurizing the fuel line on the first try......but if you let it prime twice, then it's fine.

I still need to check the fuel pressure....that will be tomorrow's project.

Multiple priming was what I did when it was worsening. Keep us posted on your pressure. You've to remove your intercooler to access the Schrader valve.

So I have to pull the intercooler to get to the valve? That stinks....I guess I'll have to hook the gauge up and then put the IC back on so I can fire up the car right? Or can I just turn the key on and see what the pressure is when the pump primes itself for a few seconds?

You can just check the pressure upon priming w/ IC off 1st. Re-install the IC & start the engine to check pressure at idle.

Thanks for this info!
 

I am pretty sure I have the same problem with my wife's R50. Changed out the filter with no improvement. Fuel rail always seems to lose pressure afte an hour or so. Will run a pressure test then go back in to check the hose.

Would you remember the hose size (inner dia.) and roughly how long a piece? Did you secure with new circle clamps or something special? Hope I can locate a submersible fuel hose here in HI.

Mahalo for the lead!

Mike G.
Chili Red '06 R53