L210 Glow Plug Resistor

[jwage]

Hi Everyone,

I am back for more! I want to test the glow plugs now. I went back and read the directions you all provided to test but I'm having a difficult time translating that in to specifically what parts I need to touch with the meter and what the expected result should be. Thanks, Jon


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[100 td]

When you measure voltage drop, you measure ACROSS the item, meaning from the start to the finish of the resistor terminals, the start to the finish of each glow plug, so from the red/black wire to the link wire and from the link wire to the ground wire, terminals on each plug. So both probes on the same glowplug, but at each terminal

EDIT: I should have put this quote here instead of the one above, but the principle is the same, but different setting on meter. When you use resistance on you meter, make sure there is no power on the circuit

The plugs could be open circuit, disconnect top wires and measure from center pin to bottom contact on each, meter set to resistance. (Does the resistor warm up?)

Go and have a look at post 37, Dave's pic, there are 2 separate connections, you currently have 2 separate wires going to them on each plug. Select resistance on your meter (a low scale something like 2 ohms or auto range) and place your probes on those 2 separate connection points on the glow plug. Remove the top wires on each before measuring.

 

[jwage]

And leave the bottom wire connecting the two glow plugs? What should it read? When nothing is touching the leads on the meter it reads 1. When I touch what should it read?

Edit: I think it should read zero. I just now read more about it and I think I get it now.

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[Dave_eng]

And leave the bottom wire connecting the two glow plugs? What should it read? When nothing is touching the leads on the meter it reads 1. When I touch what should it read?

Edit: I think it should read zero. I just now read more about it and I think I get it now.

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The first test is to touch the two meter leads to each other. Your meter should go from reading 1 to a low value, ideally 0 but probably not exactly 0.

I would remove all wires from both glow plugs just to be certain of your test.

If when you touch the two terminals on a GP with the two test leads, the reading should change from 1 to a number. Exactly what the number should be is less important now than are the readings for each glow plug the same and not 1.

I would be surprised if at least one and possibly both glow plugs are burned out in view of the inventive wiring found on your machine. A burned out GP would read 1.

Dave M7040

 

[jwage]

I confirmed the meter reads 1 when not touching anything. It read .1 when I touched the two leads together. As for the glow plugs, the left read .3 and the right read .8

Here is a closeup pic of what I am touching. Am I touching to the right spot?

 

[100 td]

Please recheck my quote in post above, I had grabbed the wrong one. But it appears you are on the right track, it's difficult to tell from your pic about the bottom connection, possibly remove the bottom washer, it is essential to get a positive/strong connection at both points to get a correct reading, the bottom connection may not be adequate without the nut being done up. Also paint on the thread will hamper the readings. To be sure to be sure.... you can also take a reading on each plug terminal to ground, meaning the threaded part to ground and the other connection to ground, this will also show if they have shorted internally. Some of this may not be necessary, but because we aren't doing the testing, it's better to get all the readings, as if I or Dave were doing it, we would automatically do other readings if we got a result that was not within our approximate specifications.
Once again please note, never have your meter selected to resistance when near a powered circuit.

 

[100 td]

Forgot to mention, depending on the manufacture/design of the plug, the bottom washer may be nonremovable, ie. part of the plug. If it just pops of or spins then remove it to get a better connection on the plug

 

[jwage]

I don't think it comes off. I tried to give it a little nudge with a flathead and it seemed solid.


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[jwage]

When I touch black to ground and red to the threaded top bolt on the GP I get 1 on both of them. I made sure I had a good connection on the ground by touching red to the engine block and got 0. And for the threaded one I touched black and red to different parts of the thread and got 0.


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[Dave_eng]

This make make things clearer on where to place the leads.

If I recall you have already removed the GP's at an earlier time or am I confusing you with another owner?

For the amount of work, it is probably wise to remove them for a physical look as well as to facilitate testing.

If I was trying to do a repeatable test, I would make up short pieces of wire with ring terminals on them, any wire gauge will do, and tighten the nuts down on them on the glow plug. In that way you are connecting your meter leads to fresh bare copper wire.

Dave M7040

 

[Dave_eng]

When I touch black to ground and red to the threaded top bolt on the GP I get 1 on both of them. I made sure I had a good connection on the ground by touching red to the engine block and got 0. And for the threaded one I touched black and red to different parts of the thread and got 0.


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The test using the engine block is meaningless. Plse try the test I just described using made up short pieces of wire

Dave M7040

 

[jwage]

I haven't removed them yet but I will now and continue testing.


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[jwage]

Here are pics.

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[Dave_eng]

The GP's fro your engine seem expensive from Messicks at $105 each.
.

I think removing your would be wise to visually check them. I cannot find a catalogue resistance value listed for them.

Dave M7040

 

[jwage]

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[100 td]

The test using the engine block is meaningless.
Dave M7040

I'll have to beg to differ on that one Dave. It's possible a plug can be shorted to ground internally, and still have a circuit. In that case, if it were the first plug, then only it would operate, as no voltage would get to the second plug. Also it could be shorted internally and be open circuit, and in that case, when the connection was made originally to the bottom terminal, no current would flow in either plug, even if the second plug was OK, as it would go straight to ground, or if it was the second plug, then only the first plug would work. It's worth checking when you aren't at the location.

 

[100 td]

Personally if it were mine, I wouldn't spend any money on old style plugs, I would go with newer 12 volt plugs and chuck the resistor as well. YMMV
http://www.soggers.ca/tractor/glow_plug_info/glow_plugs.html

 

[100 td]

http://www.lrspareparts.com/eshop/replacement-plug-for-gam100-glow-plug-conversion-kit.html

 

[Dave_eng]

Here are pics

The area of your glow plugs at the base of the threaded part for the electrical wire looks like it cannot make a good connection.

At this point, after cleaning up the connections, yopu could do a real test with the glow plugs wired up but not installed in the engine. The ground wire from the second glow plug to the engine block completes the circuit and the resistor limits the current.

Don't do it for very long but the glow plug wire element should get glowing hot. The black soot I see on them now that they are removed make me think they are not heating.

Dave M7040

 

[jwage]

Ok wired it up like this on both of them and I got .3 and .5

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