Summer starts worse than winter starts!?

simt · 10-26-2020, 07:23 AM

Hi all,
wondering if this had been anyone else's experience: that the way their s65 starts up varies with the air temperature, and that it's smoother in winter and lumpier in summer?
Here in Australia, we're heading into summer, and this week with the mornings being distinctly warmer - I got my first 'super lumpy very low revs almost going to stall' cold start in the morning. I'd missed that start up, for me it's part of the engine's special character. And I realised that all winter it's been starting up much more briskly, with no theatrics or fuss.
If this is normal behaviour, I'd hazard that perhaps it could be because the computer senses the ambient air temp is over a certain threshold, and it'll go for lower rev start to minimise internal wear whilst the oil starts circulating.

Anyone confirm they notice this same startup behaviour with their car?

-Simeon

shimmy23 · 10-26-2020, 09:11 AM

How high are you reving it? My engine will always be lumpy if I try to push it before it's warmed up.

My car starts the same weather cold or warm weather. The only thing I've noticed is in the fall with brisk cold air it loves to accelerate once warmed !

BeaterM3 · 10-26-2020, 01:50 PM

Temps here range from highs of 100 with 95 percent humidity and as cold as 1 digits. Starts the same regardless of temp. Haven't had any issues in the dead of winter at cold start up in the morning.

simt · 10-28-2020, 08:41 PM

Hmm,
I might post up a video of my starts. try and get a cold morning start vs a warm morning start. But at least the warm morning start with all the lumpiness. - For people to compare.

Richneerd · 10-28-2020, 11:52 PM

I don't know but I used to have this till I replaced all my oxygen sensors.

All the car now wants to do is make loud noises.

torrque · 10-29-2020, 10:36 AM

It is because you live in Australia, which is in southern hemisphere. The magnetic fields over there influence the gas intake as it warms up, so it is rarefied in the summer being warmer, hence the lumpy idle.
I would not worry too much... Just apply full throttle as soon as you start up in the morning for 5 seconds every day, and it will go away.

10-26-2020, 07:23 AM	#1
simt Enlisted Member 7 Rep 30 Posts Drives: F22 m235i, F10 m535i Join Date: Aug 2018 Location: Melbourne, Australia iTrader: (0)	Summer starts worse than winter starts!? Hi all, wondering if this had been anyone else's experience: that the way their s65 starts up varies with the air temperature, and that it's smoother in winter and lumpier in summer? Here in Australia, we're heading into summer, and this week with the mornings being distinctly warmer - I got my first 'super lumpy very low revs almost going to stall' cold start in the morning. I'd missed that start up, for me it's part of the engine's special character. And I realised that all winter it's been starting up much more briskly, with no theatrics or fuss. If this is normal behaviour, I'd hazard that perhaps it could be because the computer senses the ambient air temp is over a certain threshold, and it'll go for lower rev start to minimise internal wear whilst the oil starts circulating. Anyone confirm they notice this same startup behaviour with their car? -Simeon
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10-26-2020, 09:11 AM	#2
shimmy23 F15 daddymobile 2350 Rep 3,510 Posts Drives: GS X5 Join Date: Aug 2011 Location: WA iTrader: (3)	How high are you reving it? My engine will always be lumpy if I try to push it before it's warmed up. My car starts the same weather cold or warm weather. The only thing I've noticed is in the fall with brisk cold air it loves to accelerate once warmed ! __________________ -brandon F15 Glacier Silver journal
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10-26-2020, 01:50 PM	#3
BeaterM3 Lieutenant 167 Rep 420 Posts Drives: E92 335XI (sold)/E92 M3 (sold) Join Date: Jun 2018 Location: Just outside of Boston iTrader: (0) Garage List 2010 BMW M3 [0.00]	Temps here range from highs of 100 with 95 percent humidity and as cold as 1 digits. Starts the same regardless of temp. Haven't had any issues in the dead of winter at cold start up in the morning.
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10-28-2020, 08:41 PM	#4
simt Enlisted Member 7 Rep 30 Posts Drives: F22 m235i, F10 m535i Join Date: Aug 2018 Location: Melbourne, Australia iTrader: (0)	Hmm, I might post up a video of my starts. try and get a cold morning start vs a warm morning start. But at least the warm morning start with all the lumpiness. - For people to compare.
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10-28-2020, 11:52 PM	#5
Richneerd The WEEBM3 469 Rep 782 Posts Drives: E90 WEEBM3 Join Date: Nov 2019 Location: San Jose, CA iTrader: (0)	I don't know but I used to have this till I replaced all my oxygen sensors. All the car now wants to do is make loud noises. __________________ BMW E90 Alpine White Slicktop Stripped 6M 03/2008 IG: @Richneerd
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10-29-2020, 10:36 AM	#6
torrque Banned 298 Rep 650 Posts Drives: Ferrari F430, E92 M3, 335xi Join Date: Apr 2014 Location: Newton, MA iTrader: (0) Garage List 2005 Ferrari F430 [9.08] 2009 BMW M3 [10.00] 2008 BMW 335xi [0.00]	It is because you live in Australia, which is in southern hemisphere. The magnetic fields over there influence the gas intake as it warms up, so it is rarefied in the summer being warmer, hence the lumpy idle. I would not worry too much... Just apply full throttle as soon as you start up in the morning for 5 seconds every day, and it will go away.
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