Electrical issue B7100hst

[jerhutch]

Been having trouble starting the B7100hst.
I note that I'm not getting any current to the glow plugs.
There seems to be a short somewhere. Using my test light for current, putting the ground end on neg side of the battery and probe anywhere that's grounded, I get a light. When I turn the key to activate the glow plug, the light goes off, i.e., no current to glow plug.
Does not look like anyone has messed with the wiring.
I'm wondering if the switch is bad???
Any thoughts?

 

[ve9aa]

Your test light actually measures voltage not current.
Putting the test light on ground and touching grounded surfaces (and seeing light) makes no sense whatsoever my friend.

Do you own a multimeter>?

The normal modus operandi would be to put your negative lead to ground and your positive lead to the glow plug bus bar and engage glow plugs and see if you have 9-10v. On some older tractors you may have a visible glow indicator through a peep hole in the dash. Do you have one and is it lighting up?

 

[85Hokie]

First thing first ......... a "short" is a circuit that is closed -typically grounded out - in your case you have an "open" circuit not a short.

this does not make sense:

" putting the ground end on neg side of the battery and probe anywhere that's grounded, I get a light "

IF you are measuring continuity then this could be very true - but you cannot measure voltage nor amp flow with that test.

You have one of several problems.

A fuse is bad
a glow plug is bad
the glow indicator is bad
a wire is off somewhere

 

[GreensvilleJay]

There is only ONE scenario that what he says happens, does make sense.
IF the big,fat 'ground' cable from the battery -ve to the chassis of the tractor is 'open', then the test light will turn on BUT the key has to be turned 'on' to get +12 'here,there,somewhere'...

However.he says light goes OFF when the switch is ON.....

sigh.....another 'have to be there to properly diagnose' problems....

 

[jerhutch]

Your test light actually measures voltage not current.
Putting the test light on ground and touching grounded surfaces (and seeing light) makes no sense whatsoever my friend.

Do you own a multimeter>?

The normal modus operandi would be to put your negative lead to ground and your positive lead to the glow plug bus bar and engage glow plugs and see if you have 9-10v. On some older tractors you may have a visible glow indicator through a peep hole in the dash. Do you have one and is it lighting up?

Guess I'm not making myself clear. I did use my multimeter , and the light, and I see 12 volts on any metal surface, e.g., fenders, etc. So there has to be a short somewhere. This is when the key/ignition is off. Also see a charge on the glow plugs, again key is off but when I turn the key to the glowplug charge, there's no current to the plugs. Only thing I can think of is a bad switch.

 

[jerhutch]

Guess I'm not making myself clear. I did use my multimeter , and the light, and I see 12 volts on any metal surface, e.g., fenders, etc. So there has to be a short somewhere. This is when the key/ignition is off. Also see a charge on the glow plugs, again key is off but when I turn the key to the glowplug charge, there's no current to the plugs. Only thing I can think of is a bad switch.

Note that I am not touching positive side of the battery.

 

[jerhutch]

There is only ONE scenario that what he says happens, does make sense.
IF the big,fat 'ground' cable from the battery -ve to the chassis of the tractor is 'open', then the test light will turn on BUT the key has to be turned 'on' to get +12 'here,there,somewhere'...

However.he says light goes OFF when the switch is ON.....

sigh.....another 'have to be there to properly diagnose' problems....

Does not make since to me either...that's why I am asking.....??? But I do understand all of your comments. I will look again when I get home to see if I have missed something. Hope I'm not just being stupid...???

 

[jerhutch]

Does not make since to me either...that's why I am asking.....??? But I do understand all of your comments. I will look again when I get home to see if I have missed something. Hope I'm not just being stupid...???

Ok...figured it out....I just purchased this tractor a few days ago....the battery was on backwards...posing vs neg.

 

[85Hokie]

and that was the only solution left!!!!!! But I did not want to mention that!

 

[ve9aa]

Your meter won't lie. (usually)

Glad you got that part figured out at least.

What else is (possibly) smoked?

 

[North Idaho Wolfman]

Now that you've got the reverse battery figured out, do you still have a starting issue?

 

[jerhutch]

Now that you've got the reverse battery figured out, do you still have a starting issue?

The glowplug worked - started right up, ran good for about 2 minutes, then very ban noise in the engine. I shut it right down, now it won't start. It will turn over but I think the engine is toast. Not sure what to do now.

 

[jerhutch]

I moved here in Kentucky from Kalispell Mt. Not far from northern Idaho....

 

[jerhutch]

I moved here in Kentucky from Kalispell Mt. Not far from northern Idaho....

The glowplug worked - started right up, ran good for about 2 minutes, then very ban noise in the engine. I shut it right down, now it won't start. It will turn over but I think the engine is toast. Not sure what to do now.

Here's what I think happened:
After I shut down the engine, I turned the key on and noticed that the glow plug light was on. Not sure why/how... I think it somehow stayed on...got to hot..

 

[jerhutch]

Here's what I think happened:
After I shut down the engine, I turned the key on and noticed that the glow plug light was on. Not sure why/how... I think it somehow stayed on...got to hot..

I did not change anything on /about the glowclubs other than %etting them to work via battery fix.

 

[jerhutch]

I did not change anything on /about the glowclubs other than %etting them to work via battery fix.

If my assumptions are correct, engine running with glowplugs lit up, would that cause engine failure within a minute or so? And, what is the likely damage?

 

[85Hokie]

If my assumptions are correct, engine running with glowplugs lit up, would that cause engine failure within a minute or so? And, what is the likely damage?

Short answer - no, you could run the glow plugs 24-7 and the worse thing that would happen is they burn out over time.

When the engine quit - did it slam shut? OR slowly die?

 

[North Idaho Wolfman]

First try turning the engine by hand, is it turning smooth or not?
Possible issue is that a glow plug got tooo hot and it fried, broke and is now in the cylinder with the piston.
Pulling the glow plugs will answer that question!
Also pulling the glow plugs will let you spin the motor easily.

 

[jerhutch]

Short answer - no, you could run the glow plugs 24-7 and the worse thing that would happen is they burn out over time.

When the engine quit - did it slam shut? OR slowly die?

The engine did not quit. I shut it down after making a loud scraping??? Like noise. It was not a clatter...kind of hard to explain. Sure sounded like something very bad...

 

[jerhutch]

First try turning the engine by hand, is it turning smooth or not?
Possible issue is that a glow plug got tooo hot and it fried, broke and is now in the cylinder with the piston.
Pulling the glow plugs will answer that question!
Also pulling the glow plugs will let you spin the motor easily.

The engine will turn over
...no problems there but will not start.