Glowplugs worn out ??

[Dirtball]

TC33D 500hrs. , difficult to start in cold this year. Lay on the glowplugs long enough and it turns over eventually. Fuel not gelled or air in lines. Never had this problem down to 10degF before. Never had to use the block heater before-just let it warm up after stsrt up. Tried newer fuel, running extra additive. What's the life of a glow plug and any guess on cost? thanks

 

[art]

IT would be strange if they all went out at once. They can be tested when removed with a battery charger. I wonder about the cranking or not cranking as being a problem more then the glow plugs.

 

[stillwater]

Not all glowplugs have to be bad to cause a hard start. Even if one or two are bad, it can cause starting difficulty. Plugging in the block heater in this cold weather helps tremendously.

 

[kensfarm]

I'd try cycling the glow plugs twice.. and only try starting on the 2nd cycle. Plus.. check your battery.. the cold really does a number on the cranking amps.

 

[djradz]

Not sure about how the glow plugs on the 33 work, but on my 40D, they only stay on for about 6 seconds, no matter how long you hold the key. If you want it longer, you have to turn the key to "off" then back on. My old 1720 was different in that as long as you held the key in the "acc" position, the plugs were heating, even thought the light went out after 4 seconds. Are you sure you're really supplying power the whole time you're holding the key?

 

[thcri]

Dj,

Your exactly right on the 29 and 33 the plug will still be energized even though the light goes out. But you do have to make sure you don't move the key any otherwise you will turn them off. I also was told and this has come up in the discussion group before that you should crack the throttle some before starting. Now I know a lot of people are against this and is open to a lot of discussion but I did ask my dealer about it. He told me to crack the throttle some after you cycle the glow plugs and that way you warm the fuel. If you don't like the idea of having the throttle open some then back it off before you start. But this way you do have some warm fuel in the cylinder and you will start better. I done this now on mine and have noticed a better start. Give it a shot and see if it works out.

murph

 

[Dirtball]

Battery is good. Fuel flows good once it's started. This my 4th or 5th winter and I haven't needed the block heater in the past, even in the lo teens. Tractor lives in unheated barn. A diesel friend said I've been using the glow plugs needlessly in the summer cycling them on hot starts on hot days- I didn't realize that they weren't needed on restarts until this year. Did i wear them out prematurely? anybody have clue on price of a glowplug?

 

[RalphVa]

All modern glow plugs operate in parallel. So, it's highly unlikely more than one would go out.

I've had 2 Benzes, one sold at 195k miles and one now with 184k miles. None have ever worn out their glow plugs.

Ralph

 

[thcri]

Dirtball,

Even in the summer I find that I have to use the glow plugs for a good start. On restarts in the summer I still will run them a bit like 4 seconds. A diesel will cool down a lot faster than a gas engine. So if it has sat for over a half hour your cylinders may be cooler than one would think.

No you didn't hurt them buy using them. They do have protection on them if you run them too long.

murph

 

[gorm]

Dirtball,

I just looked at the wiring diagrams for my 33DA. There is a timer relay that feeds power (actually it makes ground) to the glowplug relay. The wire from the glowplug relay ends in a ring terminal that connects to the first glowplug. I have not looked at mine yet, but I assume that the glowplugs are attached daisy-chain-style from one to the next.

When glowplugs fail, they usually "fail open"; that is the heating element breaks and there is no electrical path between power (the ring terminal) and ground.

The Glow plug light on the dash is powered from the output of the glowplug relay, so when the light is lit, power is being sent to the glowplugs, when the light goes out there is no power to the glowplugs. So if the light on the panel lights you can assume that you have power to the glowplugs.

Just the same, you can verify power to the plugs using a simple test light. Just hook one side to ground, and the other side to the top of the glowplugs. Turn the key and the test light should light as long as the glowplug indicator is lit.

To test the glowplugs you will need a test meter that measures resistance (ohms). First disconect all the terminals on top of the glowplugs. Then set your meter to ohms (1-10 range) and connect one lead to ground and the other lead to the top of the glowplug.

The glow plugs should measure around 1-2 ohms or so. If it is broken (open) it will read infinite ohms, if it is shorted out (unlikely) it wil read 0 ohms. I say unlikely because a short would have blown the main fuse.

Anyway, that's my two cents. I hope it helps.

gorm