I have a 2001 7.3, hard to start when cold.oil is good and correct weight,cam sensor new gpr new.Plenty of smoke when cranking over.If not to cold (above zero) it will start,but very hard,cycle the glow plugs,crank it over it will start but shut right down,if you give it a little fuel it will stay running,but it will lobe if you keep giving it fuel it will start to run normal.I`m thinking glow plugs,is there anything else it might be.

 

Sounds like glow plugs...

 

How long are u waiting for your glow plugs to cycle? Let them cycle about 20 seconds and see how that works.

 

Still have cold start prob here`s what i`ve done so far,oil change to correct wgt,glow plug relay,checked glow plugs,all good,cam sensor,good fuel,still will not start when it`s cold unless plugged in.any suggestions?

 

X2 glow plugs, possibly also loose undervalve cover harness plug. $18 at dealer for clips to keep it together better, and if you replace the GP's, you'll be in there anyhow

 

Do you have good/big batteries

 

2 die hards new two years ago,spins motor out of truck when warm or plugged in,any other suggestions?

 

Do you know the GPR is working? Have you tested it? Ground a test light, then touch one side or the other until you find the hot side. Then turn the key on and check the other side.

It sounds like a GPR issue.

How are you testing the glow plugs?

 

not gpr,that is new,test glow plugs by pulling them out and touch them directly to a battery.could it be idm or ecm?

 

Thats not a good test. You need to see if they have resistance and what not. Theres a post somewhere on how to check them