is it bad to leave the car idling?

[beatle]

Originally posted by: Asharus
Why don't you guys just RTFM. Both my last and current car stated in the manual to start the car and immediately start driving, keeping the RPMs below 3k until out of the "blue zone".

I too, doubted the logic in this, until I presented the issue to the bimmer message boards. They informed me that the oil pressure is very low at idle and the oil will not properly circulate throughout the engine.

Not in my car. The oil pressure gauge pegs @ 90psi (only goes to 90) at idle when the car is warming up. It doesn't take long for the rpms to drop slightly.

On cars with 1-wire O2 sensors, they have to be properly heated to provide an accurate reading (something like 800F). Otherwise the car's ECU will run in an open loop that delivers a rich mixture for safety's sake. With a 4-wire sensor (many cars built in the last 10 years) 2 of the wires are used to power a heating element, allowing the sensor to come online faster and maintain a proper temperature, even if the sensor is far "downstream" from the exhaust manifold. FWIW, I have a 4-wire sensor (aftermarket) and I drive my car 5-10 seconds after starting it.

 

[arcenite]

Originally posted by: conjur
I think anything beyond 30 secs is just a waste.

I read somewhere recently, on this subject, that oil doesn't circulate as well when just idling and it could potentially cause damage.

<shrug>

My car, on avg... Takes 2-3 mins to warm up (after sitting all night)... Idle slowly drops from ~1200 to 600 as the car warms up... On a cold day, 5 mins does the trick. BTY engine is a Buick 3.3L

Bill