TC29D glow plugs

[mopwr2004a]

There is no temperature measurement. The glow plugs run on a timer then go off after 4 - 10 seconds, depending on your tractor model. At that point, yes, the light goes out. If yours does not, that probably indicates that there is a bad ground in that circuit.

I can count to 20 and the light never goes out until tractor starts

 

[tmeric7]

I'm not sure if that 20 seconds is with the key in RUN or START, or both, but if you just turn to RUN and leave it, it should go for the 4-10 seconds then stop. Whenever the key is turned to START, the glow plugs will energize for however long the key is in that position.

 

[rScotty]

I can count to 20 and the light never goes out until tractor starts

In that case I would put a voltmeter on the glow plug and see if it is still getting power. All the glowplugs I've seen do not get power that long. It's a big load on the battery, and might burn up the glow plug.


Also, the glow plug circuits that I am familiar with all control the glow plug based on how long it has been on, NOT on how hot it gets.

In most circuits, your ignition switch is just a trigger for the glow plug relay. The relay sends the high amps to the glow plug for a certain number of seconds and then turns off. The take-away is when you troubleshoot glowplug circuits where the light stays on or the glowplug doesn't seem to be heating, the problem can be in the glow plug relay OR in the glow plug itself OR in the heavy wire between the two.

rScotty

 

[mopwr2004a]

In that case I would put a voltmeter on the glow plug and see if it is still getting power. All the glowplugs I've seen do not get power that long. It's a big load on the battery, and might burn up the glow plug.


Also, the glow plug circuits that I am familiar with all control the glow plug based on how long it has been on, NOT on how hot it gets.

In most circuits, your ignition switch is just a trigger for the glow plug relay. The relay sends the high amps to the glow plug for a certain number of seconds and then turns off. The take-away is when you troubleshoot glowplug circuits where the light stays on or the glowplug doesn't seem to be heating, the problem can be in the glow plug relay OR in the glow plug itself OR in the heavy wire between the two.

rScotty

I just put new glow plugs and injectors.
Have to crank along time and starts puffing black smoke out the exhaust then finally fires up

 

[rScotty]

I just put new glow plugs and injectors.
Have to crank along time and starts puffing black smoke out the exhaust then finally fires up

Sounds like she is still too cold.

I once put in new glow plugs that didn't work any different until I put in new glow plug relays. Then it worked half a dozen times until the combo of new glow plugs and new relays pulled enough amps that it burned up the contacts and then the wires between the relays and glow plugs. Replaced the wires.... and now the old battery was not up to the chore. Replaced battery. Finally, it worked.

I think that Yanmar's "thermostart" in the intake manifold is superior to glow plugs. A few years back, several places online were selling a universal aftermarket version of a "thermostart" that is mounted in the diesel intake manifold.
rScotty