Today I had my batteries load tested, and they both tested to be good. The fuel filter was changed about 1000 miles ago and I have been using power service brand fuel additive in the truck. On my way back from getting the batteries tested I stopped by the local Ford dealership and picked up 8 new motorcraft glow plugs. I plan putting them in this weekend if my work schedule will allow. I beleive that the glowplugs are where my problem is at. Another question, I have read in the forum about people changing their fuel injector o rings while replacing the glow plugs. Is this something I should check on doing since I will have the valve covers off anyway? Thanks!

 

I replaced the glow plugs, and the truck was still hard to start. I took it to a reputable deisel repair shop today and they put it on a diagnostic computer. They recovered some stored codes and then told me that I had problems with the ebpv sensor and ebp valve tube & they both needed replaced and that a code was stored with the HPOP and that the HPOP was weak and needed replaced. I have not decided what I am going to do at this time, just wanted to let you all know the status of the truck.

 

The best tool for glow plug testing is a standard +-30 Amp ammeter. Glow plugs can fail in one of 2 ways. Either short or open.
Testing glow plugs with an open a continuity meter or Ohmmeter will work, but not if the glow plug is shorted. A shorted glow plug will pass current but it won't get hot, at least at the tip. When a resistive heating element gets hot its resistance goes up and the current flow for any given voltage goes down. When you put the ammeter in series with a glow plug and activate the relay the current will spike to about 40 Amps and decay to about 15 Amps over a 3 to 5 second period. If it's shorted the current will just go to 40 Amps and stay there because since the current is not flowing through the element (shorted at base of plug) heat build up doesn't occur and current doesn't decay.
6 inches of AWG #12 wire and standard male/female automotive bullet connectors is all you need. Also always replace glow plugs as a complete set not individually. As glow plugs age heat output per given current flows change. Replacing individual units will lead to cold jug starts (rough with white smoke) and generally harder starts in cold weather