TC29D glow plugs

[Mtsoxfan]

Is there a way to test if glow plugs working? On cold mornings, 20s, sometimes warmer, tractor has trouble starting. The glow plug light only goes on when cranking. I set throttle to where I believe 1500 rpm will be. Cranks good, but puffs black smoke and won't start. I tried putting in gear and turning key to crank so glow plug light goes on for 10 seconds. Then put in neutral and try starting. Very hard time starting. Today, when it finally started, it struggled to maintain 1000 rpm and after a minute, rpm shot up to 1600 on its own, and even with throttle returned to lowest, it took a few minutes to settle in at 1100.
My Yanmar used to make noise which I thought was glow plugs. Any help pointing me in right direction would be appreciated. BTW, cranks strong.

 

[keony]

Well, on mine the glow plug indicator light comes on with the key and goes out after 4 seconds and then is ready to start. Either your glow plugs or the relay are not working. I'm not sure how to diagnose it.

 

[Roadworthy]

Black smoke and difficult starting can be attributed to a dirty air filter. Don't ask. If you put a voltmeter on your glow plugs you will get a reading (nominal ten volts or so) on the meter. If they are getting power they can get quite hot. You can check each glow plug with an ohmmeter to see if it's good. Each individual glow plug will read about half an ohm if good. With many tractors turning the key to the left activates the glow plugs. Check your owner's manual.

 

[RickB]

The most common failure in this preheat system is the glow plug lamp timer relay. Your symptoms seem to indicate that with erratic/abnormal indicator lamp function.
Test the plug buss bar for power, ohm the individual plugs then go from there.

 

[dlctcg]

I'm not sure but I believe all the TCxxD tractors have the same concept for the Glow Plug Timer... It should energize & illuminate the glow plug dash light for 4 -5 sec's when the ignition switch is turned to the ACC/RUN position...

I can not confirm this is the correct testing procedure because it is for the TC35 - 45 series... but maybe it will help...

 

[rScotty]

SNIP....
My Yanmar used to make noise which I thought was glow plugs. Any help pointing me in right direction would be appreciated. BTW, cranks strong.

Glow plugs may or may not be powered while cranking - but usually they are not. In fact, the typical starting sequence is to turn the key to "on" and watch the glow plug indicatior light. Once the indicator turns "off", you can crank the engine.

It sounds like your glow plugs, or relay, or timer, or the wires from relay to the glow plugs are bad. It could be any of those things or all of them. Cranking while the glow plugs are being powered will drastically shorten the life of all those parts I just mentioned.
I've done a number of glow plug repairs. Old Fords were notorious for that.

You can test those parts by looking to see if the wires are burnt, turning the glow plug circuit on and feeling if the glow plugs get hot, and listening to the solenoid and timer. But best is to use a "clamp on ammeter".

The good news is that even if all those parts are bad, none of the above is harmful to the engine. You just have to replace the bad parts and they are fairly inexpensive and easy to do. Your next set will last longer as you learn more about them.

BTW, glow plugs are silent. The noise that your Yanmar made is because they alone use a different type of pre-heating system instead of glow plugs. Yanmar's "Thermostart" system is located in the intake manifold instead of within the head like glow plugs. And Yanmar's system makes a sizzling noise when it is working - just as you've heard.
good luck,
rScotty

 

[Mtsoxfan]

Thank you all for the replies. I have something to work with, now to figure out how to remove the dash out of way. Looks like 6+/- bolts inside engine area and 2 below steering column.
Snow coming to upper Vermont mountains this Friday where I live, want to make sure I can clear end of driveway.

Happy Thanksgiving

 

[Mtsoxfan]

A related question, where are you finding these pdf s? Can someone supply a link?
Thanks to all who help on here. Starting very late in life using a tractor and the support is awesome.

 

[RickB]

Take the black panels off below the instrument cowl. Two bolts below the steering column and two rearward facing bolts on each side under the hood.

 

[Mtsoxfan]

Thank you. Just waiting on temps to get into the 30s