i seem to have narrowed my no start when cold to a temperature issue. when it is cold, no start, no fuel to injectors, no lift pump prime, and no glow plugs. if i leave it plugged in overnight it fires up fine and runs all day like the issue isn't even there. my problem is that some times i just can't plug it in. (school, work, etc). is there a sensor for this circuit anywheres that could crap out when cold? or maybe a bad relay getting stuck open in the cold(water got in it or something)? i know that as long as the GPs are on the lift pump runs as to prime the injection pump. where ever these 3 circuits connect is where i'm interested in. has anyone ever seen something like this before?

I sent you a link via PM's that might help.

Need to see if there is any voltage under the hood on ENG-1 fuse (20 amp) with the key on.

Has the ignition switch been done on this unit?

as far as i know the ignition switch is original. i've never replaced it and the last thing the previous owner said he replaced didn't look replaced either. would that cause my no start when cold issue??

Mine always started cold but would stall any time after there was heat in it and I guess more current flowing through the switch.

If it's not the switch sounds like a cold contracts bad connection, have verified the ground connections from and to both batteries?

If you measure from the battery - to fuse box under the hood is there any voltage?

Have you tried "ohm-ing" the ground cable from the battery to block?

At your ENG-1 fuse when cold, do you have voltage on one terminal with the fuse pulled and the Key ON?

If not, you can verify the same at the ECM-1 fuse and Fuel Soleniod fuse. These circuits are feed from the same switch in the ingition switch.

Why plugging in would help ... don't know.

The other thing is to check your grounds. Make sure they are clean. Many of those circiuts share a common ground. I think they are on the passenger side rear of the engine.