so this morning my truck wouldn't start. Occasional fire, some white smoke, tach bouncing but no running. It's around 40F and the truck had sat for the weekend. After letting the glow plugs run for 1-2 minutes per attempt about 10 times I finally gave up, plugged the truck in and went inside. The truck hadn't been plugged in before as it's not really getting down to freezing yet. I tried again an hour later and the truck started right up and drove to work.

After sitting all day at about 45F it started fine. I pulled into the shop and started checking the glowplug system. First thing I notice is a nasty looking cooked terminal on the glowplug relay, I check for power on the switched side of the relay with the key on and got nothing.
OK, must be the relay... buy another. Stupid $55 part. When I pull the other out the battery side falls apart, it'd been really hot. OK, thats probably my problem.
Check for voltage again... nothing. Hmmm... weird. Pull the wires off, jumpers to the relay, it works fine. Positive trigegr wire is hot with ignition, like it should be. I can put ground to the other side of the relay and make it work, but the switched ground from the computer doesn't do anything. My multimeter says it's got ground, but it's not enough to light my test light or pull the relay on. I checked for current and there was to small of a number to remember.

Why wouldn't the signal be there? Bad temp sensor somewhere? Any suggestions?

Thanks!!

 

Why not install a momentary-contact push-button switch in the cab to supply this ground? Manual control is not a bad thing when you know what to do.

I'm going to do that, and I live in the sunny Southland!

Pop

 

hmmm.. because my wife or who knows who else might drive it, or because my dash is busy enough, or because the only time I want my truck to not do what it's supposed to is when I make it better, not because it's broke.

BUT, I did make a jumper for tommorow morning, and plugged the truck in.

 

sometimes when wires get hot, they melt a small portion of insulation somewhere around the connectors. Ive had it happen, if it were not so I would have told you, lol...
could it possibly be you are getting only a faint ground because of such a condition?
just my dumb 2.5 cent's worth...
Tom

 

You said the GPR was hot when you took it out. Wire could have burned in two.


CHeck this thread for more info:https://www.ford-trucks.com/forums/3...ting-gpr.html?

 

yeah, I'm an idiot. When I checked the relay after replacing it, the truck was hot from picking up the part. The temp sensor that I mentioned in my first post was just doing it's job, and the glow plugs weren't cycling when the motor was already hot. Checked it this evening and it worked fine. Thanks!

 

kbeefy, glad to hear that.

its still just a little funny

 

hey beefy, i have a friend w/ a 99 sd & he had the same symptoms. pulled the valve covers & the push rods had been rubbing on the injector & glow plug wires & shorted out. you can buy new wire sets @ the international dealership alot cheaper than @ the ford stealership. it fixed all his problems but the connector where it goes into the valve covers was melted pretty bad. looking thru wrecking yards now to find used wire loom. new one cost about $750. ouch hope this helps

 

My '99 had the same problem with rubbing pushrods.
https://www.ford-trucks.com/forums/2...or-wiring.html