B7100 glow plug indicator

[Sazhen86]

Hi

This is my first post on this forum, although I have enjoyed reading other members' posts for quite some time. I'm astounded by the friendliness and helpfulness of the members.

I've owned my B7100DT for a few months now and I'm delighted with it. Over the past few weekends I have been fixing things up and this weekend it was the turn of the electrical system. Following the wiring diagram in the owner's manual, I have it in good working order afer replacing the horn button, headlight switch and oil pressure lamp. The only thing left to do is to sort out the glow plug indicator.

The glow plugs themselves work fine and the engine starts with no problems. I have measured around 9.5V between the plug and ground whilst heating. The indicator on the dash never glows though. I measured the voltage across it and it's around 1.5V.

Unfortunately, I don't know what the voltage should be. Can anyone shed any light on this as it would be nice to have it working as well.

Thanks in advance for any help and I look forward to being a member of this forum.

Cheers
Rick

 

[Theekillerbee]

I'm not sure what the voltage should be, but the element is likely burned out. It is a fairly common problem for them to stop working after a period of time. Fortunately the part is pretty inexpensive and not too hard to replace.

 

[Sazhen86]

Thanks for the information. I'll order a new one and give it a try.

Cheers
Rick

 

[Theekillerbee]

One other thing to consider, and perhaps you are already doing this, but it takes a good 20 secs to get any glowing from the indicator, and 30-40 seconds to really get the thing bright. I think even on the new tractors Kubota recommends about a 30 second (or more, depending on temp) preheat of the glow plugs.

Good luck with your new tractor, I'm sure you will really like it.

 

[Sazhen86]

Thanks! You saved me buying a new glow plug indicator. I tried it in the dark and it took quite a while for it to glow, but glow it did. I guess it's not easy to see it glowing in full daylight.

 

[bubbaboss]

Yes... They take about 20 seconds to show up .....

After 30 seconds it does not get much brighter, but for winter strts keep holing it there for a bit longer....

 

[stuart]

I have the same engine in my B7001 - the D750. I have never seen the glow plug indicator light up. I just time it - 20 seconds in good weather, 40 or 50 in the snow. The first 2 seconds of cranking tell me if I have given it long enough.

 

[Sazhen86]

Thanks to all for the advice.

 

[Blackjack]

New to the forum, and was reading through the posts and found this one...which reflects exactly my situation.I didn't see anyone respond with what the expected voltage should read. Let me open my mouth and remove all doubt that I know little about "trons".

If my battery is fully charged (somewhere above 12.5V) - with the glow plug wire (that attaches to the #1 glow plug) disconnected, when I turn the key to warm the igniters, the voltage at that wire is 12.5V.

New glow plugs installed, wire (and connectors to the other plugs) re-attached, turn the key....and now I see only 9.3 volts between the wire (top of the glow plug) and ground. Battery remains somewhere around 12.4 Volts.

Shouldn't the voltage at the top of the glow plugs still read battery voltage?
Why the significant step-down in voltage?

It just seems as though if I had a full 12V there, those babies would glow red, AND the panel glow plug indicator would glow bright RED....sooner. As it is now, I need to cup my hand over the indicator, throw down my bifocals....and imagine it is glowing...it is, but it's very faint and takes a little imagination.

Should it still read 12Volts in a perfect system?

 

[SockPuppet]

When you add the drain of the plugs, the voltage will read lower. This is a function of the resistance of the wiring leading to the plugs and the high resistance of the plugs.

The indicator on my B8200 really never glows in daylight but it is working. If you want to see if yours works, try putting a tiny amount of oil on the element with a small brush. If it's working, it will smoke a little as it heats up.

 

[B7100]

Its exactly the same voltages on my B7100 with a new battery fitted. The voltage drop is understandable when you consider the power it take to make those 3 plugs glow and might be the reason you can't heat and crank at the same time!
Dave

 

[traildust]

New to the forum, and was reading through the posts and found this one...which reflects exactly my situation.I didn't see anyone respond with what the expected voltage should read. Let me open my mouth and remove all doubt that I know little about "trons".

If my battery is fully charged (somewhere above 12.5V) - with the glow plug wire (that attaches to the #1 glow plug) disconnected, when I turn the key to warm the igniters, the voltage at that wire is 12.5V.

New glow plugs installed, wire (and connectors to the other plugs) re-attached, turn the key....and now I see only 9.3 volts between the wire (top of the glow plug) and ground. Battery remains somewhere around 12.4 Volts.

Shouldn't the voltage at the top of the glow plugs still read battery voltage?
Why the significant step-down in voltage?

It just seems as though if I had a full 12V there, those babies would glow red, AND the panel glow plug indicator would glow bright RED....sooner. As it is now, I need to cup my hand over the indicator, throw down my bifocals....and imagine it is glowing...it is, but it's very faint and takes a little imagination.

Should it still read 12Volts in a perfect system?

Now that's classic

Scott

 

[Blackjack]

"classic"?
Thanks for the outstanding advice Trail! HUGE HELP....Keep it up!

After digging a little deeper in the shop manual, I found that the glow plugs are rated at 10V....20 amps with a resistance of 1.35-1.65 ohms. So, given that info, the readings are close to correct.

 

[Blackjack]

B7100 and Sock Puppet.
Thank you.

Blackjack

 

[traildust]

"classic"?
Thanks for the outstanding advice Trail! HUGE HELP....Keep it up!

I need to cup my hand over the indicator, throw down my bifocals....and imagine it is glowing...it is, but it's very faint and takes a little imagination.

Drinking my morning beverage after a good nights sleep your post was the first I read.

When I got to your description of observing the glow pluck indicator I found it humorous. Absolutely no sarcasm intinded. I just got a chuckle out of it, that's all. If I ofended you then I apologize.

Have a nice day,
Scott

 

[Bellinghamster]

The indicator is a wire resistor in series with the (parallel wired) glowplugs. It's glowing is an indication of current flow to the glowplugs, not voltage applied. If the glowplugs are burned out you'll still read voltage on their terminals, but they won't draw current so the indicator won't glow (or won't glow as bright if only some of the glowplugs aren't, well, glowing). If it's glowing dimly or not glowing and there is voltage on the glowplug terminals, there's a chance you've got burned out glowplugs, or (more likely) a bad connection on the buswire that connects the glowplug terminals together. Clean 'em up and tighten the knurled nuts snugly and try again. If you don't get voltage on the terminals, there's a problem in the keyswitch, wiring or the glowplug indicator is burned out (unlikely).
With all the glowplugs working properly, it takes my indicator about 20 seconds to glow visibly in the shade.

 

[Blackjack]

I did as suggested on this forum, replaced all the plugs, cleaned the connectors.
The glow indicator does glow, but poorly. The gent who suggested to paint a light amount of oil on the indicator was right on the mark....that really lets you know it's working...no doubt.

Thanks for the help.
John

 

[rednecklimo85]

When i first got my B6100 home, the indicator wouldn't work and it wouldn't start with out a lil aid. That was the very first thing I took care of. Put new glow plugs in and it fires right up, but the indicator still dont work, I'm gonna guess its just a bad indicator. My B7200 has a very bright inidicator, so for those of you that say there barley visable, they are probably at the end of their life.