And The Reason The Glow Plugs Burned Out !

[Borderpond]

Figured out the reason my JD 4100 CUT was starting so hard n the cold weather.The glow plugs were burned out! Put 3 new ones in the other day and it starts great now. Ran it for a while today .Came back an hour later and the battery was dead?? What the heck. My buddy came over and we jumped the battery and it started right up. He said ,"lets check the glow plugs while I am here ". Glow plugs were working full time.They never shut down. Battery was at 12V as plugs were taking all the power. We disconnected the glow plugs and the battery was getting 14V. Ordering a new relay switch tomorrow. I am guessing that is why the old glow plugs burned out, they were running nonstop.

 

[Tx Jim]

Ran it for a while today .Came back an hour later and the battery was dead?? I am guessing that is why the old glow plugs burned out, they were running nonstop.

If your diagnoses is correct that there's a "faulty GP relay" then why was battery "NOT in a discharged state" before the day of GP installation???? I'm just asking before you purchase elect parts as they're usually non-returnable. Granted prolonged activation of GP's will extremely shorten their life.

 

[Borderpond]

Thats a really good question. I will ask my electrician friend who was checking it out today. The old plugs were getting power before we took them out to check them. Hmmm ,now you've got me thinking.Any ideas ?

 

[JD 4520]

What is the best way to check for operation of glow plugs?

 

[Borderpond]

My friend removed the glow plugs and then hooked them up to his battery pack.One did nothing. 2 smoked a little but barely got warm. He showed me on a new one what it should do as I am pretty ignorant on diesel stuff. Hooked it up to battery pack and it quickly heated up and turned red (glowed) .I learned a little something this weekend anyways !

 

[texasjohn]

I learned something, too, thanks!

 

[SSdoxie]

Glow plugs usually fail to "open circuit", so voltage maybe present at the plug terminal but if burned out "open" the is no ground so no voltage is consumed. The relay may be stuck which caused the glow plugs to fail, and then continued starting and running charged the battery back up.
Easiest way to test glow plug is with Ohm meter. Disconnect all wires or the metal strip running to the glow plugs then test continuity & ohms across the terminal and to engine block. Glow plug resistence will vary but look for .5 ohms - 2 ohms.

 

[JD 4520]

I learned something, too, thanks!

Good information. Thanks.

 

[Borderpond]

SSdoxie, that makes sense and could explain my situation . Thanks for the info. I have been on this site for about 7 or 8 months. It has a wealth of information from a lot of experienced members.

 

[Borderpond]

Ordered the Glow Plug Controller today. $89. Should know if thats the fix in a couple days.