Now that the weather has cooled a bit, my newly acquired 09 JCW hesitates every morning for the first 2-3 minutes, particularly on more aggressive acceleration. Once warmed up it is fine. Oddly, I drove a 07 "S" a few weeks back and it did the same thing with a cold engine.

I searched the threads using the search tool and scanned the archives but came up with nothin'.

Thanks for your ideas. taking her to the dealer this week to look at it while still under the 30 day warranty from from the selling dealer. BTW, I had the Timing Chain Tensioner replaced a couple weeks ago to fix the cold start "Death Rattle" issue.

 

are you using E10 fuel?

try some E0 no ethanol fuel

warmup is much smoother in my cms all4 with E0 than E10

the octane rating and brand can make a difference too

i bet the first question the SA asks is "what brand of fuel are you using?"

scott

 

Great suggestion, I didn't elaborate too much, but I was running with 91 E10 when I noticed the problem so I tried a tank of E0 with Fastrack gas (one of the few E0 providers that most of the Hot Rodders locally swear by) and the problem persists.
I also tried completely turning off DTC (hold down DTC for at least 3 seconds) to see if that had anything to do with it, but it did not help.

Thx for the response!

 

zaz22,

I think you have already answered your question; just let the car come up to optimum temperature before driving aggressively.

Maybe I'm just old school (okay, maybe just old), but I never get on the gas aggressively until I know oil and coolant are up to operating temp. Not sure why anyone would think it is okay to turn the ignition on a cold engine block, romp on the gas and expect everything to operate the same as when everything is warmed up and flowing (fluids), not to mention the damage/wear that is done to the engine with this practice.

Don't get me wrong, I leave a lot of rubber on the twisties around here; but only after the car is warmed up.

JMTCW...

 

Thanks again for the responses.. truthfully, I am not stomping on it when cold, just normal city driving, but in order for it to NOT hesitate I have to baby it. That should not be the case in a fine highly engineered car..

 

zaz22,

I hope you didn't take my response as trying to bust your chops, as that was not my intent.

As to normal city driving; even that can be considered extreme on a cold engine. As an engineer I can tell you, it doesn't matter how well something is designed, engineered and built; you still have tolerances and constraints that can't be avoided. Oil or coolant that starts at 30 degrees Fahrenheit, physically takes time to come up to designed operating parameters (which is usually well above ambient).

You just can't bend the rules of physics, and nothing is free. You can engineer something to operate in a wide variety of environmental conditions and meet specified performance goals, but it is always a trade off for something else (efficiency, wear, responsiveness etc). There are no free lunches.

Again, maybe I'm just **** about it, but when it's chilly or cold my Coupe gets started up in the driveway or garage for at least 3-5 minutes before she rolls down the driveway and onto the road (I use this time to wipe down the Coupe, so it's a routine I enjoy)...mainly because (like you) I like to romp on the gas a bit, heading to work (and here if you aren't driving 80 on the freeway, you're liable to get run off the road).

Motor on...

 

--

 

Hey thanks, guys. Good to know i am in good company with the cold hesitation problem. I scheduled a service visit at the Mini Dealer for this Friday..(I have been there so much in the last month that the Sales and Service guys offered to give me my own Mini of Rochester). I would prefer to know if it is or is not a real problem, or just an annoyance. Being an engineer originally myself I like to get to bottom of apparent problems.
I will let you know what I learn if anything.

 

oops.... Mini of Rochester Shirt

 

dealer's service team is working through the diagnotic routines and decided that carbon build-up could lbe the problem. Initiated an inspection (taking it apart to see if there were carbon deposits around the valves, etc, and yes , confirmed there was a high degree of build up, "worse they have seen".

Solution is to blast the deposits with walnut shell grit (yes, walnut shells) and expectation is the cold start issue will be resolved AND I will experience a noticeable improvement in performance.

The procedure was completed the diagnostic routine requires a reboot of the engine management software, and this turned out to be problematic. Deaer expects my car to be done today. But until test drive and cold engine hesitation is verified as fixed, there may be more to do.

Keep you posted..............

 

oh, and I ordered a case of Techron so I can avoid this problem in the future....

 

--

 

--

 

Thanks walk0080. I will check the threads on di engine carbon build up. It was covered under warranty and the bill was over $600.

 

I've driven a lot of different minis and feel like the auto trans hesitate when u give it gas...well I know it hesitates

 

My '13 hesitates like that for the first few minutes after a cold start too. My GTI did the same exact thing during the same time too. I almost wonder if it might be an open loop trait of the ECU, since both cars use very similar circuitry (Siemens MED17 vs MEVD17.2.2).

--Matt

 

So, this morning was the test. Cold engine and absolutely no hesitation. I did even horse it a little to be sure. I also noticed the frequency of Pop-pops out the exhaust on deceleration have nearly disappeared, whereas prior it occurred on almost any moderate to hard acceleration.

I can assume that the carbon deposits were the problem and blasting it away with walnut shells and a subsequent cleanup was the solution.

However, a final step in the process was reload of the software (lost all my custom settings, too). That puzzled me, as a carbon deposit buildup is purely mechanical. Still trying to figure that one out, unless MINI figured out that 09 factory setting for engine performance was a root cause of carbon build up and now have different settings? Maybe the software was the real solution? I need to learn more about the ECU and what software releases have come out since 09, if any. I assume that software is updated periodically just like any other system.

Thanks for everyone's thoughts and help with this.

 

My guess is that the computer adjusted its program over time to compensate for the build-up, and simply cleaning the engine would invalidate the adjustments and cause issues - at least for a while (which would make diagnosis/testing the fix very difficult), so they reloaded the default settings.

 

That makes build-up even worse. When an engine is cold, the detonation is not as complete as with a hot engine, leaving more residue in the cylinder. Therefore the best thing to do is to start the engine and drive off. Not to mention that those first exhaust gasses are pretty poisonous due to the incomplete detonation. So it usually is not a good idea to breath it in. In addition, it's also stated in the manual that you should idle a cold engine for more than 30 seconds. You should start the engine and drive off.

 

ViperNL,

I think Mini/BMW are arguing (in the owner's manual) that starting and driving immediately is the quickest way to warm up a car, not necessarily the gentlest way. If you look in the manual, the statement you point out is under the "Fuel Economy" section. If the engine comes up to temperature quicker, you get a better ignition sooner (not arguing that). My point is that doing so is at the cost of excessive wear on the engine components (like the timing chain, that requires oil to be pumped in, and has very small holes for the oil to get pushed through).

Ultimately, the engine is designed to run at an optimum operating temperature. How we get there is part of this discussion (and whether performance suffers and excessive engine wear occurs before it achieves that temperature).

If gas mileage is concern for people at large (which we all know is), and telling people to just turn the key and go gets better gas mileage (as well as wear out parts that they had to come to the dealership to replace) then as BMW/MINI, I'd being saying that as well...

Let's see...make people's mileage appear higher...and guarantee business for replacement parts...sounds like a win-win for BMW/MINI.

 

Ditto.

In a stick I shift early at low RPM, in an auto, I gentley let it get up to speed down the road, so it shifts at low RPM. Then when the motor is warm, you can do what you want.

I also really hate the lack of a temp gauge!!!!

 

...there isn't a temperature gauge? How did I miss that?

 

On both our minis, I wait till the rpms drop to idle then drive. My base model takes a lot longer to get to normal idle.

 

+1

that's what i do

scott

 

--