This topic has been talked about a lot, so I thought I'd throw my 2 cents in.
Like many of us, my Mini (Emily) is prone to "stumbling" when started after sitting for any length of time. As I sat waiting for the idle to smooth out, it sounded like the engine was starving for fuel. The next morning, I turned the key to the "on" position, and waited for a count of 5, then started the engine. She started right up, with no stumbling or rough idling.
I don't know whether this is due to the weather being warmer, or Emily's being cantankerous, but it seems to work consistently.
Could it be that simple?
Any thoughts?
I figure if anyone would know, it would be the people at this forum.
Hegira

 

What year? There was a problem back in '02 or '03 but software updates mostly fixed it. It could be a change back to summer blend at gas stations.

 

Sorry. I should have mentioned that. She's an '02 MCS. The dealer in Peabody supposedly performed all possible updates last September. The car just turned 25,000 miles.
On a slightly different topic, I just started using Sunoco Ultra exclusively, and I'm seeing quite an improvement in my mileage. I didn't think it would have that big an impact.

 

Your "trick" makes sense. First, the engine computer sets air/fuel mixtures and cold rpm based on several factors, including temperature. If there was a significant change in those factors, it will take it a brief period to adjust. Additionally, if there is a bleed down of the injector pumps, they can be restabilized by the method you described.

 

I have an 04 and it was stalling on start up after sitting all night. I started using the 4 to 5 second method a few weeks ago and no more stalling.

 

I also have an 04 and agree that waiiting a few seconds with the key in accessory mode does help reduce the cold start issue.

 

I have an 05 MCS, and it stumbles when starting. Letting the fuel pump prime (waiting like 5 seconds), does help a bit, but my car will still stumble when starting sometimes. Differnt brands of gas seem to affect the stumbling issue too.

Leads me to beleive its the summer gas formula here in the North East. Car ran and started like a champ in the winter.

On a slightly related note, my Triumph motorcycle does this exact same thing. I blame it on the crappy 10% ethanol in our gas. (I only use Mobil, exxon, or sunoco.)

-Jay

 

my car does the same thing but only if the temp out side is really cold

 

I always go to the start position and wait until the red light on the fuel guage turns off before cranking. I saw a thread once that indicated the computer is initializing various systems and when that light goes off, it is finished. It works for both of our MINIs.

 

+1

 

I'll have to try this on my 03 MCS, it also has this problem. However, it may be a while before it gets cool enough around here for the problem to resurface. Summer's Here!

Edit: Hey, I just got to shift gears! yay!

 

The fuel alone can cause the cold start stumble. We changed fuel in an 04 and the cold start stumble went away.

 

i do that too on my 03. i also check my voltmeter to see how much
charge is left in the battery before cranking.

 

My stumble is off and on (05 MCS) and tends NOT to stumble after being parked for week or two, go figure. In addition to waiting thru the initializing cycle described above, I give the gas pedal one gentle press down and let up, then crank it over. This tends to lessen the stumble's severity.

 

In my '05 S, the stumble was pretty bad. Nothing seemed to help at all. I asked the dealer about an ECU re-flash for the stumble. They seemed to know what I was talking about, did the re-flash, and the stumble was gone!

However......in the past 3-4 weeks (after probably 6 months), it has returned slightly. I can only think it's reformulated summertime gas that brought it back. I have nothing else to blame. I use premium (93oct).

Ken

 

My '06 S had the stumble, but I read about the "Wait until the red light goes off" angle. Tried it and haven't seen the problem since, regardless of summer versus winter fuel.

-- mike

 

Guess I need to give this a try.