riss6270

Ive got a little problem. I have a 2004 F-250 diesel. If the truck sits outside and isnt pluged in at night it wont start. If it gets below 60 it wont start. This should be so. What could cause this? I have new glow plugs but dont want to tare it apart if thats not it. What can i check first that would save me time and money. could it be the glow plug relay?? Any help would be great

 

wwb

The glow plugs, if working properly, draw about 90 amps.... enough to keep the alternator output voltage well below the normal 14.5 volts.

When you start the truck, note the position of the needle on your voltmeter.... let the truck idle for a couple minutes, and you should see the needle suddenly rise a fair amount after a minute or two. Or, if it's dark in the early morning, start the truck, turn on just the parking lights and let it idle for a couple minutes... you should see the lights suddenly get brighter when the glow plugs are shut off after a minute or two.

If you don't see this happening, the glow plug relay is the likely culprit, though there could be other wiring problems.