kubota glow plug indicator not glowing/hard cold start

[gemini5362]

The glow plugs AND the indicator are all 'in parallel'.

One side is positive and other ground, the engine being the ground.
That being said, one side of the indicator is ground and the other positive.

In that way the plugs AND the indicator all heat (glow) at the same time.
(glow plugs, get it!)

The indicator is sort of 'an out of body' glow plug.

In parallel circuit they all get the same voltage at the same time and if one is burnt the others still work.

Series, one goes, none 'glow'!

Glow plugs being high amperage devices by nature are more suseptable to bad connections, so clean all contacts.

Piloon I will freely admit I have not looked at the manual so I am just guessing here. If you know for sure please advise me but here is how I would expect them to be hooked up. I would not expect a parralel circuit to the glow plug indicator that would not tell you if you had power to the glow plugs or not. I would expect the wiring to go something like this. +12 power from the switch to the glow plug indicator. then wiring from the glow plug indicator to the first glow plug, then run a jumper wire from the first glow plug positive terminal to the positive terminal on the second glow plug, then a jumper wire from the positive terminal on the second glow plug to the positive terminal on the third glow plug. etc etc. the current path would be something like this ( I am going to keep this simple I am aware that most current theory has current flowing from negative to positive.) The current would run through the glow plug indicator to the first glow plug then through that glow plug through the threads of the glow plug to the engine block which is ground. at the same time current was applied to the first glow plug it would be applied through the jumper wire to the second glow plug and through the jumper wire from the second plug to the third plug etc etc. You are correct when you say the glow plugs are in parralel and have the same voltage through them. However current in parallel circuits add up by wiring them in series with the indicator you see the result of the current through all of the glow plugs at that indicator. One possibility of a problem could be with jumper wires. If you have power to the first glow plug and their is corrosion on the end where it goes to the second one you would not have power at the second one and if that is jumpered to the third one then you would not have power to it either. Also if you have a DVM they only need a few microamps to read. It is possible to have them read a full voltage in a high impedance connection but the connection have too much resistance to allow the current to make the glow plug work. I would probably clean all my connections to the glow plugs. If that did not fix the problem then pull the glow plug out and see if it is heating.

 

[neucam]

My older Kubota's glow plug indicator has not worked for a long time, it has not effected the ability to heat the glow plugs, so it does not seem to be hooked in series, other tractors may be different, I just preheat a few seconds and the engine starts fine. I don't miss the indicator. If 15 secs does not make the the engine start right up when cold, I repeat. Never a problem, though it sits in an enclosed garage.

 

[PILOON]

Hi

My tractor setup (Mitsubishi) has the glow plugs AND the indicator in parallel.

My friends B7100 is also wired the same and in fact his indicator is missing but the plugs still glow! (confirming an all pareallel circuit)

Basic logic has it that they all need to be parallel

In my old GMC with 6L engine would actually start even with a 3 burned out glow plugs BECAUSE it was in parallel, started kinda rough however.

Another easy test is to turn the switch to 'heat' (or glow) and quickly place your hand on the plug body--it should feel warm! voltage at the plug terminal is no test, only confirms power is getting there.

In many automotive installations trhey use fast glow plugs as car drivers want it now!
by and large tractors are the slow glow variety which will last much longer as they are more forgiving.
The fast glow is almost a dead short so it kinda melts easily if the timing is off.

 

[gemini5362]

Hi


Basic logic has it that they all need to be parallel


Actually basic logic would have the indicator in series with the glow plugs. If the indicator is in parralel that just tells you that you have power to the indicator. I am not disputing the way you say that your stuff is wired just saying that basic logic would have that in series with the glow plugs in parralel.

My arguement on having jumper wires between glow plugs would still be a valid reason why you can have the first one or two work and then none of the others past that working.

 

[stubbornrichard]

Its running good again, first of all i would like to thank very much everyone who helped me out and gave me ideas on TBN. without them i probably still would be lost. Ok so now i get to explain what the problem was.... the first glow plug by the output shaft was shorting out causing all the other plugs to not even work and eventually that one burnt out and didnt work at all, so i took out the one right next to it and found out it works great, i put it back in and then disconnected the one that was shorting out and bypassed it so basically the other three were the only ones connected, preheated for 20 seconds and it fired up first try, even on 3 preheated cylinders, so now i have to spend the 15 dollars on a new glow plug and replace it wich takes me about 5 minuits, im glad it wasnt a big problem

 

[gemini5362]

congratulations on getting it working again. I am glad it was not something more serious than that

 

[Mr Hydroseed]

I own a New Holland l553 with the Kubota v1902 engine in as well. This thing has never started in the cold very easily. I installed a block heater that needs to heat the engine overnight to get it running. I haven't looked really, really hard yet but I can't find 4 glow plugs, only one thing that somewhat resembles one towards the rear of the block? Does this sound right? Also, does anyone have that part # for the generic auto parts store glow plugs? As soon as I say Kubota they freeze and can't do anything. Thanks!

 

[joecdeere]

All L553's & L555's with the Kubota engines have glow plugs. Attached is a page out of the New Holland Parts book that will give you an Idea of location. If you look under the injector lines you will see all 4 in a straight line with a heavy wire linking them all together. You need to learn how to activate them, you're really killing that starting circuit not using them. I can't remember on that model if there is a button you hold down by the key switch, or if you rotate the key to the left to heat, then turn right to crank

 

[orop]

Hello Stubbornrichard,

Its running good again, first of all i would like to thank very much everyone who helped me out and gave me ideas on TBN. without them i probably still would be lost. Ok so now i get to explain what the problem was.... the first glow plug by the output shaft was shorting out causing all the other plugs to not even work and eventually that one burnt out and didnt work at all, so i took out the one right next to it and found out it works great, i put it back in and then disconnected the one that was shorting out and bypassed it so basically the other three were the only ones connected, preheated for 20 seconds and it fired up first try, even on 3 preheated cylinders, so now i have to spend the 15 dollars on a new glow plug and replace it wich takes me about 5 minuits, im glad it wasnt a big problem

Not sure if you still monitor your post from 6 Years ago but I am curious to know if your glow plug indicator worked again properly after you fixed the problem?

 

[rono16]

I've got the same problem on my B7100 the glow plug indicator doesn't light and my hot feed from ignition switch to to glow plugs melt when trying to preheat. It keeps burning out my indicators. Please help.