Reluctant Duramax

[BlackSilver]

Engine is 2003 DuraMax, 82,500 miles

 

This fall/winter the engine is a reluctant starter on cool mornings (20's and 30's). Previous winters it started easily on even the coldest morning (it gets down to minus-20 here in Minnesota).

 

If I have the block heater plugged in, it will always start. If I don't have the block heater plugged in, it is a bear to get started.

 

Once started, it runs beautifully, good power, good mpg, and restarts easily all day long.

 

Fuel filter is new. Air filter is new. Batteries check strong on a load test. Glow plugs are drawing power (meter on the battery shows voltage drops about 1.5 volts when the glow plug relay clicks in, then rises back up nicely after the relay drops out).

 

Any ideas?

[GM-Tech]

There's not an easy answer for this. SOmeone needs to plug into this thing and take a look at a whole bunch of different parameters.