I have been reading threads on this issue for days. The threads always seem to be open ended with lots of gray areas. I'll start with it being an 05MCS with 70,000 miles. Last night it took almost 15 minutes of trying at work and it finally started. This issue only appears if the car is parked outside, when it's parked in the heated garage it starts normally.

Before I just start changing fuel filters, fuel pumps, spark plugs, coils, I wanted to pick some brains here. I am getting no check engine lights, so no codes yet.

 

If the spark plugs have those 70K on them, replace them. Also find out where the Coolant Temp sensor is for the engine management system and test it with an ohm meter. Coolant Temp. sensors on a vehicle are generally negative thermistor types, which means their resistance value goes UP as the temps or coolant gets colder, and goes DOWN once an engine is running. If your sensor is off from where it should be reading on a cold engine with these outside winter temps, it will make starting harder since the Engine ECU isn't fueling the car via the injector opening times correctly[ time that the injector is held open to allow fuel into a cyl.]
Having an easier time starting the vehicle once it's in a heated garage points to these 2 things to check, since spark plugs will be getting more fuel thrown at them to ignite when your car is parked outside and it's much colder, versus being in that heater garage, and if they're worn, they aren't as likely to do their job correctly.
You could have a fault coolant temp sensor that hasn't gone open, or gotten SO far out of spec that it's setting a Check Engine light yet.
If your spark plugs ARE newer/ not original, then the fuel system is where I'd start for a hard cold starting issue.

 

First thing I would do is test the battery...and check to see all connections are clean and tight...
It is possible for it to have ample capacity, but low voltage, so a slow crank...
The fact it starts when warm, but worse when cold makes me think that it should be tested...
I had a battery in my car that would still start it, but was actually about 10 volts after it sat..crank was a bit slow...The battery, a 6+ year old redtop optima, tested as "sulfated" or maybe an open cell...in either cases, sound fine in my garage. But cranked slow outside...
It still has lots of capacity....so could still crank, long, but not fast...
Any mods?
If running excessively rich...like it has injectors, but no tune...could also cause this...

 

+1 Battery is always the best place to start with cold weather issues. It also turns out to be a fairly easy and cheap fix.

 

Thanks for the replies. The battery is newer, but that doesn't mean it's good so that's where I'll start. Plugs are easy as well and it's probably due since they may be original. The car has absolutely no known mods on it, but it was purchased used. The temp sensor doesn't look like its that bad to get to either.

12.62v sitting
14.23 running

It's an actual BMW battery, only 4 months old. So I guess I'll rule that out.

 

Battery voltage looks good anyways...
Might want to try gas from a different station...
In cold weather, fuel typically is sold in a different winter blend...one reason us emissions rules, other reason is vapor pressure...the winter stuff evoprates easier, helps starting.....
This can be an issue with cars stored it transported to a diffent area until they get fresh fuel.

 

Changed plugs today, the ones removed definitely looked like originals. It's been pulled outside so it will be a good test to see if it made any difference.

I still believe this is a fuel issue, but I am willing to try anything at this point.

 

Okay, we will wait for good news,

 

Does the car have a pulley?
With the stock pulley, the plugs are good for about 100,000 miles...they are NGK, and say BMW or mini on the insulators, and have 4 prongs....
Once a pulley is done, the sparkplugs should be changed on the JCW schedule, which means at each "inspection", with is every 30,000 miles....

 

No pulley. It was on the TO DO list, but this little issue needs to get straightened out first.

 

Changed the coolant temp sensor and still the same starting issues. Its has to be a fuel issue at this point, I need to get some fuel pressure readings in the morning, but the saga marches on.

 

Whoa, you jumped ahead to just changing the sensor without just taking an ohm reading of its resistance when parked outside?
Hopefully it's cheap and easy to change??
Okay, the saga Does continue..

 

$20 and 30 minutes to change. I tried to get some Ohm readings, but its hard when the temperatures get real cold. You will only know if its working or not, not if its working correctly.

Here was a good chart to go off of.
http://workshop-manuals.com/mini/coo...ams/page_1361/

Actually if you make it down to the point you can pull the plug off the back of the sensor, you might as well take the extra 30 seconds to change the sensor.

 

The fuel pressure is just shy of 60lbs so I can rule that out also. Zippy mentioned that it may be bad fuel, and I am starting to think he was/is right. I have pretty much run out of things that could be wrong.

 

One thing you can try...
Next time you buy fuel...and it will be cold, try putting in a few gallons of midgrade...then mostly premium... And see if it starts any better.... I know a few folks at one point were told by dealers to try using slightly lower octane if they had starting issues....guess if you poured a bottle of iso-heat...the isoproplol gas line antfreezse, you would be doing the same test...getting a slightly more volitle fuel mix in to see if it fires up better in the cold.
I take it the voltage is still good after it sits?
Car sounds good when running right? Smooth and good power right?
Know that very low compression motors (worn rings) can be hard to start when cold...doubt it is your issue. But kinda running out of simple stuff...

 

The fuel was actually something that crossed my mind last night and I topped off the tank with 87. As far as the compression is concerned, my compression tester won't be able to reach down in the spark plug holes without an adapter. The adapter should be too difficult to make and wouldn't be a bad idea to test periodically to watch for any signs of degrading engine life.

Yes, the voltage sits right where it should be, running and sitting. Except for the starting issues, the car run perfectly.

 

I know you said you've checked the battery voltage, both running and sitting, but have you checked the voltage drop when starting? I don't think it's supposed to drop below 10.0v. I had a car about a month ago that would drop to 4-6v when trying to crank. That meant the cold cranking amps weren't high enough to turn the engine, and consequently a bad battery. (The battery was 'fine' unless I left a door open or something stupid that ran the battery down.) Turning the lights on for two minutes prior to cranking will bleed off any residual charge and give you a better reading.

Easy thing to check, just thought I'd throw another idea on the pile.

 

I hadnt thought of that, probably because I was doing it myself. I will give that a shot. All ideas are appreciated, thanks.

 

Definitely check the voltage drop, I lost a starter in the dead of winter. It had been taking longer and longer to crank out in the cold until it literally melted the wire that goes to the starter housing. Couldn't for the life of me figure out why it wouldn't start, but a new starter made it fire up within 2 cranks.

Funny enough, when the wire did melt, it took an 8 month old battery with it.

 

Well, battery voltage checked out fine, it looks like an instantaneous loss of less than .5vDC then it returns to over 12 volts. It has evolved into a newer issue that may start to narrow down the problem. Now since the weather has warmed it fires instantly, but about 80% of the time it sputters and dies on the first few start ups. When it is doing it, no amount of throttle will correct it.

 

Might want to do an advanced search on cold start stutter.

 

I just spent the last two hours reading through threads that ultimately lead nowhere. My biggest gripe with this whole thing is trying to read fuel pressure. It pretty easy to get to the Shrader valve, but the fact that I had to rotate the drivers side IC mount down to get the gauge on makes it impossible to get reading while it running. The noise it makes with the IC off was a nice surprise early in the morning.

The fuel rail looks to a system made for the NA motor that was adapted to the SC motor.

 

Has anyone had any luck taking it back to Mini to have this issue fixed. This car has very little time left at this rate. As much as I enjoy driving it, I purchased it as a work beater and since I never know if it will start or not, it doesn't go to work, just sits in the garage.

I'm just tired of trying to find a fix to a problem that really doesn't seem to have a fix.

I'm not opposed to dropping it off at Mini, but I know it will be a full raping.

 

Where are you?
Maybe you are near a local shop with good mini experience somebody can recommended.

 

ne il.