Hi. I have a 1984 F250 S/C 4x4 Diesel that has just started to experience a longer than usual cold start problem.
Specifically, when I put the key in the ignition and turn it to the position right before the start position, the WAIT TO START light does not come on nor do I hear the glow plug relay clicking. This just started happening this past week. It worked fine before (the light came on, the GPs clicked and then the light turned off & the clicking stopped after about 12 seconds).
The weird part is that once I do get it started (after cranking for a few minutes {in 30 second intervals}), the WAIT TO START light will come on intermittently until the engine is a bit warmer (this part of the process seems normal, as it used to this when everything was working good too.....) then it will go off (so I assume my WTS light bulb is just fine). Once the truck is started it runs fine.
Now just as FYI; I have a new GP controller in the engine that I replaced when I did a head gasket job (just weeks ago). And like I said it was working fine just a few days ago.
Does anyone have any idea where to look? Could the GP relay be bad (or going bad) and not work before starting but begin working once running?
Any help is appreciated. Thanks.
Scott P.

 

Check your connections on the passenger side firewall. this happens to me sometimes to, wiggle the wires around and it should go.
Marko