Glow Plugs

   / Glow Plugs #31  
Yes, I did remove the bus bar. I even removed the glow plugs from the engine. Results each plug measures less than 1 ohm. #1 measures .2 ohms #2 measures .3 ohms. and #3 measures .5 ohms which means they should be good, right? Now the kicker, when I test with a 12V batt. They will not glow and they never get warm to the touch. The batt. I used is at 12.6V. I rechecked the voltage to the bus bar I am still getting 12.6V
Sounds like you are on the right track.
BUT how about grounds?
A weak ground often can conduct voltage at low amperage and fail to carry high amps.

Another test would have been to power each plug individually outside of the engine.
For that even less than 12 volt source should warm them up.
Momentary powering @12 volts should make each one glow or at worst warm/hot to touch.

A glow plug is nothing but a fancy resistor designed for momentary usage.

Easier still is to create a good ground from battery immediately adjacent to the plugs and then apply power to each plug and feel for heat.
 
   / Glow Plugs #32  
I tested them by using a 12V batt. Neg. lead went to the threads on the unit. (-) and the pos. lead went to the electrode (+). held the leads for about 30 sec. The plug never lite up and never even got warm to the touch. So I think they are bad, unless I am doing something wrong. What do you think?
I think you found your problem. The glow plug is shot. As long as you know you had a good connection on each end, it seems the plugs are shot. Get some new ones.
I also noticed that the glow plugs are 10.5V. Do think that I might have blown them by testing them in this way?
What do you mean the plugs are 10.5V? Is that the rating marked on the plug?

I doubt they would fail with a 30sec test at 12v...

I don't think you should have to wait 30 seconds on a good plug. I'd expect that in a few seconds you would have a hard time holding on to it!
 
   / Glow Plugs
  • Thread Starter
#33  
Sounds like you are on the right track.
BUT how about grounds?
A weak ground often can conduct voltage at low amperage and fail to carry high amps.

Another test would have been to power each plug individually outside of the engine.
For that even less than 12 volt source should warm them up.
Momentary powering @12 volts should make each one glow or at worst warm/hot to touch.

A glow plug is nothing but a fancy resistor designed for momentary usage.

Easier still is to create a good ground from battery immediately adjacent to the plugs and then apply power to each plug and feel for heat.
I tested the plugs out of the engine with a 12V batt. and they would not even get warm. I plan on replace the plugs. Thanks for your input.
 
   / Glow Plugs
  • Thread Starter
#34  
Sounds like you are on the right track.
BUT how about grounds?
A weak ground often can conduct voltage at low amperage and fail to carry high amps.

Another test would have been to power each plug individually outside of the engine.
For that even less than 12 volt source should warm them up.
Momentary powering @12 volts should make each one glow or at worst warm/hot to touch.

A glow plug is nothing but a fancy resistor designed for momentary usage.

Easier still is to create a good ground from battery immediately adjacent to the plugs and then apply power to each plug and feel for heat.
Pulled all the plugs and tested them using a 12V batt. and didn't even get warm. I am going to replace the plugs, thanks for your input
 
   / Glow Plugs #35  
It sure sounds like your plugs are shot. The .2 ohms reading is a little confusing it should be an open reading. It should not change when you touch the tester terminals to the plug. I suppose there is a slim chance that when they burned out the shorted internally but for you to get any reading on a burned out plug is highly unlikely.
When you get your new plugs, test them with your ohmmeter before installing them, just to check and see. If you decide to test with a 12V source, be sure you are not touching the plug when you do. Remember a 12W soldering iron will melt metal and these plugs should be putting out about 80W!
 
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  • Thread Starter
#36  
It sure sounds like your plugs are shot. The .2 ohms reading is a little confusing it should be an open reading. It should not change when you touch the tester terminals to the plug. I suppose there is a slim chance that when they burned out the shorted internally but for you to get any reading on a burned out plug is highly unlikely.
When you get your new plugs, test them with your ohmmeter before installing them, just to check and see. If you decide to test with a 12V source, be sure you are not touching the plug when you do. Remember a 12W soldering iron will melt metal and these plugs should be putting out about 80W!
Got my new plugs today. Checked them with the ohm meter. they test the same as the old ones. 0.5-0.9 ohms. Have not tested them with a batt. yet. It has turned cold here so I will wait a couple of days, it should warm up by then. I am really confused, when I watch the internet on how to check them with a ohm meter, It tells me to set the meter at 200 ohms (which is the lowest setting) and test them. When I do that, I get nothing. 0 reading. both the new and the old test that way. don't know what is going on.
 
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  • Thread Starter
#38  
Hi Bob, Good video. I Watched the video and done what he did. I have a Fluke 175 true RMS Multimeter I used to test them. It turns out that all the old compared to the new ones where very different. The old ones were wide open and the new ones run about 0.2 ohms. So I am glad that I bought new ones. Have not glow tested them yet however. PS Just got home from town. Tested the glow plugs using a 12V batt. They took about 30 sec. to start glowing. I installed them and checked my amp meter, it was drawing around 30 amps. I started the tractor. I was disappointed because the tractor did not seem to start much better. Thanks for your come back.
 
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   / Glow Plugs
  • Thread Starter
#39  
Hi People, Replace all three glow plugs. They were bad, would not glow. The new ones takes about 30 sec. to glow. Thanks for all your feed back.
 
 
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