When I was removing the glow plug wires to check the glow plugs, some of the insulation on 3 of the glow plugs disintegrated in my fingers as I was turning the glow plug wire before pulling the wire off of the glow plug. This is the insulation at the top of the glow plug. I wasn't removing the glow plugs just checking them for continuity. These plugs checked good. 3 others checked bad. Will this hurt the glow plug to run them like this? I'm planning to replace the bad plugs and now figure I need to replace these without the insulation to. Just not right this week. By the ay, my truck is a 1987 F250 with a 6.9 N/A.

 

no, it will not hurt anything to run without the insulation on the wires.
the insulation prevents you from getting a short if a piece of metal hits the engine and wire when the glow circuit is working.
when you change the glo plugs, buy some heat shrink tubing and put it on the wires to cover the connectors.. that is all you will need to do.

 

I'm talking about the ceramic insulation on the glow plug, not the insulation on the wire. Sorry if I described it wrong.

 

well, if the ceramic came off, i would change the plugs.

for the small price of the glow plugs, i would just change them all and be done with it for another 15 years.

 

That's what I thought and that's what I'm going to do. Just wanted to know I wasn't the only one who thought that way.

 

AMAZING!! New glow plugs and she starts the first time. Went to the Oreilly's close to me (they told me they had the ZD9's) and the guy pulls out AUTOLIGHTS. NO NO NO!! Ended up going for a bike ride to get the plugs. Oh well. it was a beautiful day for a ride.

 

i am testing my glow plugs with a fluke multi meter set on resistance. i notice that when the glow plug is out of the truck, sitting on a bench i get no resistance. an open. when i put said glow plug in the engine i get 1.5 ohms. why is this? also, what caused me to test them is last night i went to start my truck and upon turning on the key the glow plug relay went on and off repeatedly really qiickly. i figured bad g/p. i tested all of them, found one bad one and replaced it. now the relay comes on for about 5 seconds then goes of and on really quickly. it used to come on for 10 to 15 seconds depending on how cold it was. could this be a bad relay?

 

If it's a solid state unit you may have one more bad glow plug in the system.

 

If you are testing between the threads on the glow plug and the electrical connector on the glow plug, and it shows open, replace those glow plugs.

1.5 ohms is higher than normal, you are probably getting resistance from somewhere other than the glow plugs.

.5 to 1 ohm is ideal resistance