I have a 2000 7.3 and the past month I have had a very random issue with my truck not starting in weather below 50. Some mornings when it's below 50 and I plug in the block heater I have no issues. There have been a few morning when I haven't plugged it in and it starts fine then as well. This morning it was about 40 and I didn't plug the heater in and now it wont start. I just replaced the glow plug relay and still wont start.

Once I get it running it runs perfect and starts back every single time. As it cranks it sounds like it's not firing if that makes any sense.

Any help would be greatly appreciated.

 

Test the relay. Dose it stay on? Mine would click off to soon there by not heating the cylinders. Could also be a glow plug problem. Two or more bad glow plugs will cause hard starting or no start at all.

 

If no glow plug led mod, then go by the seatbelt icon. Once it's off, then try and fire ur up. The WTS light is bogus.
. Can also ohm out the gp's at the valve cover plug. There's a method somewhere on here/google for a how-to and numbers to go with...

 

First step would be to determine that the GPR is working. When the engine is cold have someone turn the key on but not start and test the right post on the GPR for power. You could also jump across the GPR with a big screwdriver for a minute or more then try to start the truck and see if it starts.

 

As several members of the team have said, this is the place to begin the trouble shoot.

 

Thanks for all the reply's. What was odd was when I hooked up jumper cables from my wifes suv it started immediately. Unhooked the cables, turned off the truck and it wouldn't start back until I hooked up the cables again. I did go through and clean all the batter connectors very thoroughly and it starts better but it hasn't been cold enough to see if it fixed the issue. I went to autozone and had them test both batteries and they way there were good batteries.

 

Did they isolate each battery when they tested them?

Have you checked all your ground connections on the block also? They can start to corrode over time.

 

I would put a Volt meter on the batteries with the key OFF (should be 12.5 volts) and then do the same with the key ON engine OFF and see how low they are going with the GPR on. These trucks need a lot of juice to get the glow plugs running, turn the starter and fire the injectors. Start with batteries before you start chasing parts that may be fine.

 

autozone might not test them for 1000 amps, maybe only 500


if jumping them works then you might have weak batteries like me


I also have a corroded pos cable on pass side that might be working against me too