Ford 1910 Glow plug voltage

[Jeff Gammon]

What should be the voltage at the glow plug when the key is turned to the preheat position? Right now I am getting about 9.5 volts. I looked at a wiring diagram and believe there is a resistor (the indicator on the dash) in the circuit that would cut the voltage but I am not sure by how much. It seems to take quite a bit of time for the glow plugs to heat up enough for the little tractor to start.

Thanks,'
Jeff

 

[PILOON]

There will be a voltage drop as the plugs draw heavy current, that's normal.
The dash resistor is most likely your glow indicator. It will glow when ready to start.
On a tired battery you probably won't read 12 volts after a heat cycle or 2.
A good battery will still read 12 V even after a couple of heat cycles.
Also there are 2 types of glow plugs, fast heat and slow for want of better description. Theory being that the fast glow units will burn out faster and more often than the slo types.
My guess is that you have no problem. My 3 cyl engine often wants 2-3 glow cycles on colder days even when plugged in for an hour or 2.
Just looking at the wire sizes leading to the glow plugs are your indicator as to current draw.
Make sure that all contacts and grounds are clean and tight.

 

[rayikeo2]

What should be the voltage at the glow plug when the key is turned to the preheat position? Right now I am getting about 9.5 volts. I looked at a wiring diagram and believe there is a resistor (the indicator on the dash) in the circuit that would cut the voltage but I am not sure by how much. It seems to take quite a bit of time for the glow plugs to heat up enough for the little tractor to start.

Thanks,'
Jeff

How long are holding the key to the glow plugs, in seconds?
What is the outside temperature when you are having delayed starting?

I give my 1700 20 seconds when temp is above 50 and 30 seconds when temp is 30 or lower.

 

[Jeff Gammon]

I gave it about 40 seconds the other morning when the temp was 38 F. I had to do it 2 times before it would start. I hadn't checked the glow plugs yet to determine if they are all good. I have never had a diesel, but assume if I had 1 bad out of 3 it might cause a problem

 

[rayikeo2]

I gave it about 40 seconds the other morning when the temp was 38 F. I had to do it 2 times before it would start. I hadn't checked the glow plugs yet to determine if they are all good. I have never had a diesel, but assume if I had 1 bad out of 3 it might cause a problem

That is more than enough time to get things heated up. Next question, where do you have the throttle set when heating the plugs? What works for me is to have throttle closed for the first 30 seconds and then open it to the running position (about 1500 rpm to start) for the next 10. Then crank with the throttle in that position. Other posters may do it different.

Sometimes a bad ign switch can cause a slow starting problem. How many hours on your tractor?

 

[Jeff Gammon]

1800 hours on my tractor. Why does it make a difference what position the throttle is in while heating the glow plugs? I never thought of that making any difference till you get ready to start it, but I am new to diesels

 

[jinman]

There will be a voltage drop as the plugs draw heavy current, that's normal.
The dash resistor is most likely your glow indicator. It will glow when ready to start.
On a tired battery you probably won't read 12 volts after a heat cycle or 2.
A good battery will still read 12 V even after a couple of heat cycles.
Also there are 2 types of glow plugs, fast heat and slow for want of better description. Theory being that the fast glow units will burn out faster and more often than the slo types.
My guess is that you have no problem. My 3 cyl engine often wants 2-3 glow cycles on colder days even when plugged in for an hour or 2.
Just looking at the wire sizes leading to the glow plugs are your indicator as to current draw.
Make sure that all contacts and grounds are clean and tight.

+1! A good battery and tight connections are the keys to a good glow lamp cycle.