7.3 Crank but no start - batteries or glow plugs?

Quick302Pony · Nov 1, 2013

I have a 1997 7.3 that will crank, but no start. I put a charger on the batteries last night, and it fired this AM, but it took some cranking to do so.

I have also noticed that the battery gauge won't move until about a minute or so after you start the truck, and when it does move, it will go straight to the middle.

The batteries are from 2011. I'm leaning towards batteries, but someone mentioned the glow plugs as well.

Bugman · Nov 1, 2013

Get your batteries load tested. From what you describe on the volt guage the glow plugs are working but you could have some bad ones and even a couple can cause problems starting when it is cold out. So if you batteries test OK then the next thing to do is to test the relay and glow plugs.

jschildm · Nov 1, 2013

I agree with getting your batteries load tested. The volt meter will stay down for a minute or two while the glow plugs are cycling, that is normal.

You can use a volt meter to test continuity of your glow plugs through the UVCH harness. It definitely doesn't take but 1 or 2 to make these trucks hard to start.

Quick302Pony · Nov 1, 2013

Great, thanks!

jschildm · Nov 1, 2013

There are 4 plugs to the valve covers (2 on each side), each plug has 5 wires. The two outside wires on each plug each go to a glow plug. If you use a DVM and check continuity to ground, they should be from 0.1 to 2 ohms (I believe). If they are higher than that or an open circuit then they are bad or going bad.