On our last trip we had a number of issues which resulted in replacement alternator and one of the three start battery's ( other checked and rechecked )
On a sub zero morning engine was sluggish and required boost switch to start , as it fired up the volt meter fluctuated between 11v -14v for about 4mins then settled to 14v , started as normal rest of day .
Next morning sub zero and same fluctuating voltage .
It's now in shop and after 2hours of diagnostics they want another 2hours ! Anybody had this problem
Jimmy,
Are you running any engine preheat (block heater) before starting in the sub-zero conditions?
When to use block heater (http://www.foreforums.com/index.php?topic=16970.0)
Fluctuating voltage is NORMAL in really cold starts, as the INTAKE MANIFOLD HEATER cycles on/off. And, it is a BIG draw.
And, absolutely, use the block heater if you have shore power for 2 hours or so before starting.
Great advice , thanks you
Yes I left block heater on overnight , will call garage now
My guess is also sketchy main ground. I would pull and clean the ground to the chassis and the one to the starter itself.
Easy to diagnose. Just put a test light or voltmeter on the intake manifold heater and see if voltage drops coincide with the heater turning on and voltage rises with it turning off.
Brett
You were on the money .
Thank you