I am having a hard time starting at mornings below freezing. I'm getting a lot of white smoke at initial start up, and a very rough idle. What I'm curious about is whether this is a grid heater problem or a fuel heater problem. Any thoughts?

 

watch your voltage when your wait to start light is on first thing AM.

my guess is your sucking some air in through small cracks in the fuel lines. The small cracks seem to suck more air when the fuel becomes heavier (thicker) with cold weather.

 

But would that small amount of air getting in cause it to put out so much white smoke? It seems like that would only smoke a lil bit and just make the start real hard on my pump more than anything.

 

Plug it in below 40F.

 

It won't be the fuel heater. It's main use is to prevent gelling while driving and idling. It doesn't do much during starting.
It sounds to me like you might have a failed preheater relay, and only one grid is coming on instead of both. It's fairly common.

 

Allright, looks like I'll start tearing into the heater grids once I have time and a multimeter.

I would be plugging it in, unfortunately I live in a shady apt complex and there are no outside outlets (fortunately my extension cord didn't get stolen with all my stuff because it was frozen to the ground that night ).

Thanks for the help, if it is the relays, what type of relay should I use to replace them (i.e. is there another car or make that I could buy them for that would be better)

 

Use a non-grounded Ford starter relay. Available at any autoparts for around $10.

 

Not sure on your year, but on the first gen trucks it is very common for the "thermistor" to fail which causes the pre-heat grids to not work. If you unplug it, if it is bad the grids come on for the full 40 seconds, then the wts light flashes. I tried this on my 05 and all it does is give a couple codes, so I know it doesn't work on the third gens.

 

any particular year or model on the ford?

 

79 f150

4 barrel

 

They used the same relay from the mid '50s until early '90s, take your pick.