Air-Cond On When Starting

[clint]

Guys, Need some advsie. How can i keep my air-cond off when starting ? All this while i thought all E46's air-cond will automatically come on when starting. Until i saw my cousin's E46. When he switch off his air-cond, it remains off even after you've start your engine. Regards, Clint

 

[Mouse]

Guys,

Need some advsie.

How can i keep my air-cond off when starting ? All this while i thought all E46's air-cond will automatically come on when starting.

Until i saw my cousin's E46. When he switch off his air-cond, it remains off even after you've start your engine.

Regards,
Clint

no need switch off lar, i never turn off my aircond and radio, just start vroommmmmmmmm.........go china. If u r paying a few hundred $$$ k for a car that need to switch off aircond b4 starting, then i think can save $$ buy proton better

 

[LCP]

I think Proton also no need to switch off aircon when starting... Kancil too...

Bottomline is when you crank the engine, electrical power to other "non-essential" items are automatically cut off... it is a basic design rule for all self-respecting car manufacturers when designing the ignition switch.

 

[8080pbmw]

only make sure you have your ICE volume turned low after the previous night blasting. just joking.
I never bothered with these steps, not even waiting for the check engine or service indicator to be switched off before driving off.
But I do practice on be gentle on the throttle when the engine temp. is in the blue section.

 

[meetoo]

Begging your pardon guys, but the AC compressor is driven directly by the engine through a belt and magnetic clutch. This is the same whether Kancil or BMW. There is a bit of extra load for the starter motor and battery if the clutch is engage when you crank the ignition. It's not a big deal, but the idling speed drops about 200rpm if you switch off the AC, so it's small but still substantial amount of power. I always switch off AC before switching off the engine.

Clint, my E46 AC stays off like your cousin car. Maybe you have a faulty switch or relay?

 

[clint]

meetoo, what year is your E46 ? My cousin is a 2003.

 

[absidian]

Begging your pardon guys, but the AC compressor is driven directly by the engine through a belt and magnetic clutch. This is the same whether Kancil or BMW. There is a bit of extra load for the starter motor and battery if the clutch is engage when you crank the ignition. It's not a big deal, but the idling speed drops about 200rpm if you switch off the AC, so it's small but still substantial amount of power. I always switch off AC before switching off the engine.

FYI the clutch is electronically controlled. So it goes without saying that the clutch is already automatically disabled during cranking on the bimmer and most new cars.

 

[pussy]

aiya.. just listen to LCP's reply..

if the e39 has this problem, i bet the air con techician made tons of money already..

when you start the car, even the radio cuts off, air con is disengaged..so dun worry on the air con load..the ecu will adjust the idle speed load..

 

[meetoo]

I don't think the ignition is designed to cut the AC, radio, lights, wipers and whatever else you leave on. They just experience a stop because of the current drain to the starter means not enough juice to power them momentarily. When we have a weak battery and the car take longer crank to start, we will automatically make sure everything else is switch off first.

It up to the individual whether to switch off or not. I've always practice that and will continue. Clint, mine also 2003, but I don't think the AC will designed to automatically come on, regardless of year of manufacture. What if you live in a cold country? My sister only uses her AC in the summer in UK.

 

[David Yong]

I don't think the ignition is designed to cut the AC, radio, lights, wipers and whatever else you leave on. They just experience a stop because of the current drain to the starter means not enough juice to power them momentarily. When we have a weak battery and the car take longer crank to start, we will automatically make sure everything else is switch off first.

+1 very true & agreeable!

It is only lazy people who don't switch off anything especially radio & aircon when they switch of their car.

 

[tchdaniel]

air con on

Agreed with Meetoo,he is absolutely right,switch off ur AC n start ur car....ur starter will last longer also due to lesser load to turn ur engine.

 

[E46Fanatic]

Someone told me that this behaviour is programmable. Just like the the re-circulation function of the A/C. For 5+ years I pressed the re-circulation button each time the air cond comes on. Only recently found out that its programmable to stick to re-circ mode when A/C comes on. Apparently its a simple few second job to re-program the A/C.

Hence the different behavious of your E46's. Newer batches of E46's have this preferred settings already set I believe.

 

[Whalesith]

Clint,

E46fanatic is right. To determine if your air cond can be switched off everytime you start you car depends on your YEAR OF MAKE. apparently those 2002 and above or certain 2001 model can be reprogrammed to off the air-cond when you start your car.

To check if your car can be programmed to do that, you can go to M-Speed, ask Meng to plug your car to the diagnostic, then he'll tell you if it can be done.

my ride is e46 2001 and mine cannot be reprogrammed.

 

[SarJeePekAi]

Buddies 'n' Baddies,

Can this procedure be done to an E36 vintage 1998?
Do pardon me but all I have read so far applies to E46ers.
Any one kind enough to enlighten us E36 owners.....?

banyak thanks.

 

[LCP]

I don't think the ignition is designed to cut the AC, radio, lights, wipers and whatever else you leave on. They just experience a stop because of the current drain to the starter means not enough juice to power them momentarily.

Actually, I hafta disagree, when the key is in the "crank" position, items wired to the "non-essential" category will experience a full cut-off, I have studied the wiring diagrams of most cars, BMWs included and can confirm this. The aircon, radio, wipers, etc., "stop" experience is really a full power cut-off experience. If it is not a full cut-off, the effect will be just like the slight flickering/dimming of dashboard lights (oil pressure, charging lights, parking brakes, etc), when you crank the engine.

Unless of course the car wiring has been illegally modified, then the effect can be different from what the manufacturer intended it to be...

 

[meetoo]

Maybe you are right LCP. I haven't studied the ignition process. BTW, where do you see it in the wiring diagram that there is a cut-off?

Anyway I think it's a good habit to switch off everything before switching off the engine. Then the accessories don't come on immediately after the cutoff (or brownout) when you release the crank position. That still a big drain on the battery right after the huge drain of the starter crank. I like to sequentially switch things off and let the engine settle into lowest RPM before switching it off. And sequentially switch things on a few seconds after starting the engine.

It's the process control engineer in me...that is the way we do things to put the least stress on the entire system

 

[pussy]

once i had my e34 fan run direct from battery if the key is turned on, so when i crank up, it was hard to get the engine to fire up.. once i relayed it to a switch, then it was just 2 cranks to start up.

 

[ramsing]

before i crank the engine, i will turn the key to an on position, wait a few seconds then crank. but during the waiting period, the radio will on. and when i crank, the radio doesn't cut off. its still playing.

i haven't tried with the aircon on before starting. i'll try tomoro. hmm....funny.

 

[INNOVATOR]

My year 2000 E46 318i !.9, cudn't switch the aircon off. This means when the aircon is switched off manually and the engine is shut down; the aircon will start up automatically when the car is started.

But in both my year 2004 2.0s, the aircon remains off even when the car starts up. Its a choice and I believe the guys can just reprogramme your aircon to remain off.

 

[David Yong]

Mine got a very special function which I'm sure u guys dun have it. When I get into my car and either before or after I start my engine, I just clap my hands and the aircond will switch on automatically! hehehe.....