Glow plug questions

[CubMon]

When you pulled the glow plugs, how did they look? - very much soot? Was the soot greasy or dry?

The best way to test a glow plug is with an amp meter in series with the power lead and compare readings between the three. The heater coils have such low resistance that the normal digital multimeter will only indicate that the heating coil is in tact. Rare that you would need all of the glow plugs at the same time......

Hard to believe that the ignition switch feeds all that current...most glow plug circuits go through a relay so that the switch only carries a small relay coil current.

Check your fuel filters. One of the first symptoms of dirty filters is hard starting.....the fuel to the injectors is 'wide open' at starting so any starvation would show up then and at the WOT position as well. Not many people run their engines all the way up against the governor so this condition shows up when cold starting.

 

[handirifle]

Cubmon
Thanks. I was looking at the engine yesterday, oddly enough, because after doing a major no-no, running it out of gas , I got to see it a lot closer. Thankfully I had read threads on this forum about how to get it started again, and after 15 min of cranking and bleeding, off she started. Whew!

Anyway, being totally new to diesels (not to engines and I have a fair understanding of how diesels work, fair) , I assume the 6" square box with the fuel lines coming out is the injector pump, and the filthy greasy hard to recognize blob next to it is most likely the fuel filter housing.

Doesn't look like it's been removed in years.

Does this filter go inside this unit or is it a spin on type affair? It LOOKS like a cartridge type filter.

Would a NAPA store handle these? There are no MF dealers anywhere in this area.

 

[handirifle]

I checked and NAPA does carry the filter and will pick one up. Tried it this AM with various throttle settings, andno difference. There is a ton of black smoke that comes out the exhaust when the throttle is wide open, and trying to start, so I'm betting the filter isn't the issue. I hosed the engine off and the filter actually looks fairly clean (I can actually see it now), but will change it anyway to be sure.

CubMon
How many amps should the glow plugs draw? I do have an Ampmeter, left over from my AC repairman days.

 

[CubMon]

I checked and NAPA does carry the filter and will pick one up. Tried it this AM with various throttle settings, andno difference. There is a ton of black smoke that comes out the exhaust when the throttle is wide open, and trying to start, so I'm betting the filter isn't the issue. I hosed the engine off and the filter actually looks fairly clean (I can actually see it now), but will change it anyway to be sure.

CubMon
How many amps should the glow plugs draw? I do have an Ampmeter, left over from my AC repairman days.

I'm not sure what they draw, but that's some data that is stated in your service manual though. I would make a current draw comparison between them....

I believe you're right about the filter not being the issue - black smoke when it starts and WOT - like an injector is dribbling fuel. That's probably the next check - the injectors. Sometimes you can remove them and reconnect the lines with the injector inverted to see what sort of pattern they spray. Other than that you could take them to a diesel repair shop have have them popped with a tester. If an injector is dirty, they'll stick and will also drip fuel into the chamber - that fuel is hard to ignite that is wetting the surfaces - the fuel needs to be atomized to a mist.

Was the soot on the glow plugs greasy wet?

 

[handirifle]

Yes it was sooty, not wet, although not super heavy. I am saving for a factory owners manual. At $183 , I don't have that much free cash. Retired!

 

[ray66v]

If the smoke on start up gets worse, when the cold weather gets here, it is the injectors.

You can try a large dose of a ULSD fuel approved injector cleaner.

Auto trans fluid always did a good job at cleaning diesel injectors, however, it is no longer recommended with ULSD fuel.

 

[CubMon]

Yes it was sooty, not wet, although not super heavy. I am saving for a factory owners manual. At $183 , I don't have that much free cash. Retired!

I feel for your situation...I can never retire. I started too late investing and then the crunch took what I had gained. I should have taken that union job way back when it was offered so that now the tax payers would be paying my way - easy street for union retired...

The owners manual shouldn't be that bad...you must mean the factory service manual. That would be good to have but a lot of info that you don't really need.

Have you looked at the air filter? I'm thinking about this rich start condition with black smoke and the revved up black smoke with the dry soot in the chamber. The engine appears healthy but just is either getting too much fuel or not enough air. Looks like at medium speed, the ratio is OK....

 

[handirifle]

Yup! Pulled it out this afternoon. FILTHY! I know better, should have looked at this first off. Will see in the morning how well it does. Got some "amazing oil" for the fuel injectors, supposed to clean em up. Will put that in the tank.

Went to pull the fuel filter filter out and fuel kept pouring from the tank. Does not appear to be a cutoff valve. So I tightened it back up till I get better light, to see if I am missing something.

 

[Transit]

As far as warm here, it's usually somewhere in the low seventies or later in the day, mid to upper eighties. Once the tractor has been started and running it doesn't need anything but turning the ign switch and cranking it over.

At 70-80 deg. F. you should not need to use any glow plug heat. Above 40 Deg. F. there should be enough compression heat to start the engine. Going by my engine, a plug will draw about 5 amps cold and as it heats up the current will drop to 1.5 amps each. You should also see the tip glow?

On the plugs, what would I use to clean them if, hopefully, that's all they need, a wire brush or some solvent?

This may come as a shock; the glow plugs are always ON. The heat from the last combustion cycle will keep the plugs glowing all the time and the plug tip should be hot enough to burn any soot off. Shock # 2, the engine is not a true Diesel but a Hot Bulb engine, the hot Bulb being the glow plug.

http://www.spiritus-temporis.com/hot-bulb-engine/hot-bulb-pseudo-diesel-development.html

 

[ray66v]

the plug tip should be hot enough to burn any soot off.

As engines get old, the world gets imperfect.