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Old 05-11-2008, 11:26 PM   #30 (permalink)
diesel_john
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"With a fully charged battery and with the alternator off, when the engine is cold it uses about 7 amps, but when it warms up it drops to about 3 amps. All in daylight with no accessories on. I still haven't figured out what is on when cold that draws the extra 4 amps, not that it it matters much."



during cold startup many cars have heated 02 sensors which draw more current, as well as the injectors draw more when cold because they are open longer, and their resistance is lower. the mass air flow goes thur a burn off to clean the wire sometime during startup. the idle air control is open further during startup. the ignition coil is cooler and has lower resistance. the fuel pump is cooler. all the relays are cooler and have lower resistance.

Last edited by diesel_john; 05-14-2008 at 01:01 AM..
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