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

Mike, run that pressure test before you dig.
My split hose:
Attachment 150930
My fix:
Attachment 150931

If this is causing your trouble, look for SAE30R10 submersible fuel hose. 5/16" or 8mm.i opted to use a U-shaped tube than letting the hose bend.

Well just a little update on my issue.....it seems to be getting worse. This morning I turned the key on and off two times to give the fuel pump two chances to prime the system......that's be working for about a week. Well, this morning that wasn't enough. It still fired up and then died.....I had to prime it a third time, and then it fired up and ran great.

The part that confuses me is that other than the starting issue....the thing runs strong. I can run it up through the gear under full throttle and it doesn't skip a beat. If the fuel pump was so weak that it can't even prime the fuel system with three tries......why would it be strong enough to supply enough fuel for wide open throttle running? And it still seems to only be an issue if the car sits for more than 4-5 hours or so....if it sits for anything less, it still fires up on the first try. Very strange. :confused:

I picked up a fuel pressure test kit at Harbor Freight last night......I guess this weekend I will be doing some trouble shooting.

Well, mine went thru what you're having now then gradually worsened to needing multiple priming & yoyo. The worst it got before I found the culprit, the car died on me a coupla times. That got me really stumped. Don't wait for it.

Well I just pulled the IC off and hooked up the fuel pressure gauge. When I turn the key on and the pump primes, the gauge jumps right up to 51psi. When I turn the key off the pressure seems to be holding. After the car sat for about 15min the pressure was down to around 49 psi.

It sounds like the fuel system is good to go. Now what to check? Could it be a MAP sensor? I'm a little stumped ...I was expecting to find a bad fuel pump.

Tried the purge/breather valve yet (mentioned earlier)?

No, I guess that will be the next step. Could someone explain to me what the purge/breather valve actually does...and how it works?

That should be good news that your pump is good!
Aside from the vent valve, try a new Coolant Temp sensor. It's near the T-stat.
A failing or bad Coolant Temp sensor will feed the ECU erroneous readings. You might be starting lean when you're supposed to go rich or vice versa resulting in hard starts. This cheap part was among those I swapped out. Mine turned out to still be good so I got into the other suspects 1by1.

Other causes are the ignition system. Plugs, wires, coil pack. Go OE w/ all these if you decide to do refreshing.
You can do easiest or cheapest 1st. The breather valve is pricier than the Coolant Temp sensor, leads & plugs.
Hope you hunt it down soon.

Fuel vapour is created in the fuel tank when the engine is not running. The EVAP system stores this fuel vapour in a charcoal canister.
– when engine is cruising: purge control valve opened, small amount of fuel vapour is drawn into the intake manifold and burned.
– when the engine is idling (starting cold): purge valve prevents any vapours from entering the intake manifold and causing excessively-rich fuel mixture.

A faulty EVAP system will only affect engine driveability when the engine is warm.

The plugs and wires are brand new...only about 2000 miles on them. Whatever it is...it's related to the temp of the engine. After its totally cooled after sitting for 4+ hours it takes a few tries to start. If its already warmed up, or only been sitting for an hour or so it fires right up.

I'm thinking that my next step will be the coolant temp sensor. That makes sense... I can understand why that would be causing the problem. Is it pretty easy to get to the sensor?

The fuel breather valve doesn't make much sense to me...so I'm going to leave that alone for now.

One quick question on the coolant temp sensor....if it was bad and giving strange readings, wouldn't the temp gauge in the car be acting funny also?

Do you have a scangauge or anything alike? It'll tell coolant temp from the obd unlike our temp gauge that constantly sits at the middle. This will help you check the sensor's health. If it says cold or hot when it's supposed to be the opposite, you'd know its bad.
Again, be glad you won't have to dig into the pump.

I have a copy of the BMW diagnostic software on my laptop....and an OBD2 cable. That's a great idea! I will hook it up tomorrow morning after the car has sat all night and see what the coolant temp is saying when I hook up the lap top.

The only thing that I can't figure out is that when I try to start it for the first time and it dies, it doesn't run long enough to heat anything up at all....so why does it start on the second try. And why does it start when I turn the key on and off a few times....what would that have to do with the coolant sensor?

Very strange...but I guess I will know more in the morning when I do some more troubleshooting.

In this electronic age, nothing is simple anymore. In your case, I'm guessing 2nd starts run the engine instantly as fuel has already been fed into the injectors from the initial start.

But when I first turn the key the fuel pump will prime and run the pressure up to 50psi before I even try to start it. With that much pressure, those injectors should already have plenty of fuel at their disposal before they even need to open.

Getting ready to hook up the laptop this morning and see what other kinds of info I can collect.

Let's see what you'd find thru the obd.