View Single Post
Old 09-02-2009, 04:48 PM   #12 (permalink)
cfg83
Pokémoderator
 
cfg83's Avatar
 
Join Date: Dec 2007
Location: Southern California
Posts: 5,864

1999 Saturn SW2 - '99 Saturn SW2 Wagon
Team Saturn
90 day: 40.49 mpg (US)
Thanks: 439
Thanked 532 Times in 358 Posts
jkp1187 -

Quote:
Originally Posted by jkp1187 View Post
Well, I've had to replace starters on several of my cars - 1988 Chevy Celebrity, 1995 Chevy Beretta, 2000 Chevy Impala. Granted, all of them were beyond 100,000 miles at the time of the replacement, but I take it more or less for granted that I'm going to have to replace a starter at least once.

Note that the above replacements were made before I made it a point to turn the engine off at long lights.

For what it's worth, BMW's owners manuals claim that four seconds of idling is the break-even point for idling versus shutting off. Of course, shutting down and starting up for every 4-second delay sounds like you're asking for trouble. My rule is that I'll shut down if I know the wait will be more than 20 seconds AND if the oil is at operating temperature.
I haven't replaced my starter yet (knock on virtual wood), but at 182K miles, it's gonna happen sooner or later.

I believe the 4 second idling number. In colder climates, one caveat to this is unheated oxygen sensors (aka oxygen sensors that only start to work when exhaust gases heat them up to "temperature X"). Heated oxygen sensors are heated using electricity from the battery, so they stay heated as long as the car's key is in the on-position. At extended stops in cold weather, an unheated oxygen sensor could cool off to the point where it is no longer operating normally. The ECU/PCM can detect this state and will spend more time in open-loop mode, which would burn more fuel.

I also wait for the engine to warm up before employing engine off. I won't using engine-off unless I already know the timing of the light. 20 seconds sounds about right for me too.

CarloSW2
__________________

What's your EPA MPG? Go Here and find out!
American Solar Energy Society
  Reply With Quote