7.3 Will not start when it is cold, I have the glow plugs wired on a toggle switch, I have replaced one side of the the uvc gasket it was melted on the each one of the connectors on the end closest to the front of the truck. If I keep the truck plugged in it will start up but if it is unplugged it wont start at all......the fuel line where it goes into the injector pump (think it is in the injector pump) it is behind the fuel filter anyways what ever that line is leaks would this cause it to be hard to start when cold.....Not hard it plain wont start

 

Are the glow plugs and glow plug relay good?

 

Well see the glow plugs all work they are hooked to a toggle switch inside the cab and when you turn on the key you flip the switch till the wait to start light goes away then flip switch down and start truck or try to...

 

But have you tested the glow plugs them selves to see if any of them are bad?

 

Yes they are all brand new, I replaced them...found out all the old ones are good but replaced em anyways

 

Ok, does the switch control the coil side of the glow plug relay?

 

I have not looked into it to be honest but i know when i flip the switch the glow plugs all get hot, and if you leave the switch off and try and shut the truck down it will stay running (not to sure how it is hooked not a mechnic of diesels and it was done before i bought the truck)

 

If all the GP's are working then its time to pull the valve cover and check the armature plate clearance on the injectors.

 

If the truck stays running when you turn the key off and the switch is on, then the glow plug relay is bad. It is back feeding power to the PCM and making the truck keep running. The two small wires on the GP relay are the coil wires. One is a constant 12v and the other is a ground controled by the PCM. that is the one getting power back fed through to the PCM. If it were mine, I would replace the relay, eliminate the switch and wire the relay correctly.

 

But is that goin to help it start when it is cold? And can I get a diagram of how it is soposed to be wired