Having an annoying cold start issue. 97 7.3. The truck will not start without a fight if temps are under 50* outside. If i plug in, shes fine. Checked glow plug relay, all is good there. Check resistance on all my glow plugs. All read at 1.5 ohms, but cyl #2 is up around 5.7 ohms. How does one have that much resistance? Also, terminal in the pig tail for cyl #3 is burnt out. I have 12v power to every glow plug, however. Could the one glow plug with high resistance, and the one with burnt out terminal cause this hard start? Any info appreciated

 

Also, new engine and glow plugs 2500 miles ago. Its my first diesel so im still getting used to the thing.

 

I can't see 2 bad glow plugs make it start hard in 50* weather

but if you have one burned out one in 2500 miles you have a problem.

What brand are they? If ANYTHING other than Beru or Motorcraft, pull them NOW

 

They are zd-11 right from the dealer. What could cause one to burn out so quickly? Im pulling my hair out on this.

 

1.5 should work, but based on my personal observations, it's not quite ideal.

All 8 of my new ZD-11s were 0.8 ohms dead on. So were all 8 of the Berus that I pulled out.

Are you sure the relay is good? 12V to the glow plug side when someone first turns the key? And for how long does it stay at 12V? Maybe the controller is bad.

 

Yes i only lose maybe .5v across the relay. And if i check voltage at the plug for the glow plug, i have a 12v reading. Glow plugs stay on for roughly a minute. Give or take.

 

You have me stumped

 

May be your problem. Loss across the large terminals should be no more than 0.3v.

 

The feeling is mutual haha

 

The relay is a cheap one. About a year old.

 

^^^^ Easy confirmation - use a jumper cable, jump across the two big terminals (or go direct from the battery + to the big terminal that connects to the GPs). 20 seconds or so, then see if that helps it start.

 

I will give that a try in the morning when the engine is cold.

 

I have been doing as modpogue suggests to start my truck the last two days (awaiting my new relay), but after 5 seconds of jumping to the glow plug post, the truck fires right up.

 

Check your - battery to engine cables for corrosion and tightness.

 

Connections seem okay all around. I will see about jumping the relay in the AM