Glow plug heat.

[steve 444]

I have 12v at no 4 plug, but they will not heat up. Manual that i have says that the system is neg ground, but one i got (original) from international says that the system is pos ground??. Can anyone help with this heating problem.

 

[Owen Aaland]

Without telling us what you are working on you are not likely to get a good response.

 

[Janicholson]

If the plugs are getting 12v, it does not mean they are getting hot. They are a "light Bulb" like thing. If the volts are there, it probably burnt. Some IH are series plugs, and when one goes out, they all quit. I do not know which yours is, but it is common to find 12v in the open circuit. Even if they actually operate on about 3 volts each. If they are parallel, all will get 12v. if series they will collectively get 12v. Testing series is disconnecting and checking input terminal and output terminal (to next plug) with a ohm meter. Near zero ohms is good, high resistance or open is no good.
If parallel wired, disconnect and check continuity from terminal to ground. Near no resistance, good, open Bad. Jim

 

[Allan in NE]

Polarity doesn't matter. Voltage does.

There are both 6v and 12v glow plugs. If you were sold a 6v plug, they will fry on a 12v system.

Put a test light between 12v and the plug. If it doesn't light, the plug is bad.

Allan

 

[rustred]

myself i like to visually see them work, even after checking with ohm meter. such as on the 282 diesel. i remove them and check each one on a battery, for 3-4 sec.once starts turning red disconnect it, as its good.
the old 5.7 olds diesel did use 6 volt glow plugs on a 12 volt system but it used a relay to cycle them on and off about 3 times to prevent burnout and faster heat up and less battery drain.

 

[steve 444]

My mistake OWEN. I have a inter 444.

 

[JimB2]

Hi Steve, if you have a 444 then the glow plugs are wired in series and each glow plug measures about 1.2 Volt to ground. The heater on the dash drops the voltage from 12V to 6V then each glow plug drops about 1.2V. Take note of the way they are wired. If you are measuring 12V at the one closest the rad, that glow plug is either burnt out or the ground to the block has a bad connection.

On these glow plugs, DO NOT test them on a 12V or they will burn out.

There is a replacement kit that will replace all these older glow plugs with newer faster heating 12V glow plugs.

See conversion of glow plugs by jdemaris at: http://www.yesterdaystractors.com/cgi-bin/viewit.cgi?bd=farmall&th=959462

JimB
Glow plug conversion

 

[Owen Aaland]

(quoted from post at 00:45:56 07/19/15) My mistake OWEN. I have a inter 444.

That is why I asked. There is a big difference between the two systems. JimB2 has given you the correct solution.