Lights on while cranking?

[colinmitchell111]

When its cold out without the truck plugged in, do you guys have everything turned off when you cycle and crank the truck. I know how finikey these trucks are with voltage, I don't want to kill my ficm. My turque app doesn't start reading for about 20-30 seconds after the key is tured on so I can't see the voltage at inital key on when the glow plugs and the ficm is going. I was wondering how much the lights, heater, and whatever else affect the voltage. My truck has the auto lights but I haven't been leaving the switch on auto because its dark when I have to cold start my tuck at work.

[dfuzz78]

Voltage when the glow plugs are on is 11.5-11.9. Lights & heater use 1.5-2.0 volts, and the alternator won't kick on until the glowplugs are off. So I would wait 30 seconds to 1 min before turning on all your stuff.

[RRF985]

I always have as much stuff off as possible when cranking the engine cold.

[Lilpooh]

Originally Posted by RRF985

I always have as much stuff off as possible when cranking the engine cold.

Me to, maybe we're just anal!!

You Tube

You Tube

[Coach73]

lilpooh, your voltage is much better than what I'm reading on my SG2, I pulled my batts out today, 3 yo Exide 850 CCA, because I was seeing 9.5V at the start on a cold day and just over 13 running down the road, the terminals were extremely dirty and water level was low. I have a digital battery load tester and they both passed, so I topped them off and cleaned the terminals and actually saw 14 running around town. I'm going to run it down the road tomorrow and see how high it gets. Coach. (by the way I was gonna put Motorcraft batts back in).