Glow Plugs

[cjd]

As I sit around waiting for my SF97, I decided to replace the glow plugs on my M1123. Being my first time, I was pretty surprised at how cooked they were. Only 1 plug was in decent shape. The rest were bulged, bent, cooked, or had holes. Now she starts and runs much better!

So, what is it that damages the plugs? Is it just something that happens over time, from overuse of the heat cycle, hot starts, cheap plugs, or something else. I was wondering if there are techniques to extend the life of the plugs.

 

[tgejesse]

DO NOT TURN YOUR TRUCK TO RUN WITH NEW GLOW PLUGS BEFORE YOU KNOW YOUR BOX IS GOOD.
Check a glow plug lead and make sure you’re not getting a constant 24v. I have a 1123 that came from Yermo with the same situation.

I replaced the plugs and then burned them right out again.
If you have a bad box, get a new one from camotek and never have plug issues again.

 

[cjd]

I checked the leads for good voltage, and I checked one for voltage cutout. Is there anything else you recommend?

 

[tgejesse]

I checked the leads for good voltage, and I checked one for voltage cutout. Is there anything else you recommend?

If the wait light is acting appropriate and you’re getting ~24v for 5-8 seconds and then it stops you should be g2g.

 

[cjd]

Thanks!

That brings up the question...I am not interested in going to a manual box, but is there a more reliable plug controller worth buying?

 

[diesel_dave]

Thanks!

That brings up the question...I am not interested in going to a manual box, but is there a more reliable plug controller worth buying?

Which do you have now? I have a KDS yellow label that I thought was crapping out but it turned out the temp sensor had gotten water in it. I fixed the damaged sensor and it's been working great ever since. My old plugs were mostly all burned out but they weren't damaged looking at all. I'll keep an eye out for how long the new ones last. The yellow label seems to apply about 5 seconds of heat then 1 second blips every few seconds for about 2 minutes. I'm not sure if that afterglow is what damages the plugs or if they just died from old age.

 

[Action]

Just my .02, my last hmmwv had yellow label kds. I let the truck sit at idle until the afterglow cycle finished. I didnt drive right away. I never had an issue.

 

[cjd]

I don't know what's in it...still catching up on everything, but it's the one it came from the Marines with.

 

[TOBASH]

You need to go underneath the left side of the dashboard and take a picture of the box. That picture will also have a picture of the label. Above your left foot as you were sitting in the truck and behind the dashboard there is a 4 1/2“ x 10“ box that is upside down. That has a label on it. Take a picture of it and post it and then we will be able to tell you what type of box you are running in your truck.

Just telling us that it is from the Marine Corps does not give us information as the boxes are all interchangeable

 

[MarkM]

The label will look something like below.

 

[cjd]

Thanks, I'll get under the dash eventually...the last 4 days I have been under the floor changing fluids. Funny, I was rating the truck as one of the easiest vehicles I have ever worked on. Then I got to the tranny today. That sucks. I have owned Jaguars with the exact same 4L80 tranny that were many times easier to change the fluid than this truck. With minimal planning they could make it so you do not have to remove the cross member...and the exhaust crossover could have easily been located 1" forward.

Most of all, why can't they use a pan with a plug to drain it before you loose 3 quarts all over the driveway? Every truck I have owned has a drain plug, so you can lower the level before dropping the pan...or no obstructions so you can lower the pan level. Next fluid change I will be ready with a pan with a plug.

So, is there a "best" box, and/or a "bad" one?

 

[GuntherRommel]

You can thread your own drain plug for the future

 

[cjd]

My controller is the Nartron shown in your picture. Is it fairly reliable?

Yep...NEXT fluid change I will be ready for adding a drain plug. This time I didn't have the time to dig one up. I am just floored that a truck wouldn't have one from the factory.

 

[GuntherRommel]

Maybe they want you to change the trans filter every time you take the pan off

 

[cjd]

That is the case with all cars and trucks. Not having a drain plug has nothing to do with the filter, though. All the trucks (Cummins/Allison) I have owned have had drain plugs, along with all the upscale cars...Jag, Rover, Cadi. I've also had a lot of cars WIthout drain plugs. Bottom line, there is no way to change the filter without making a mess unless you have a drain plug to lower the fluid level before lowering the pan. It just seems strange the HMMWV is good on every level...then no drain plug.

 

[frauhansen]

That is the case with all cars and trucks. Not having a drain plug has nothing to do with the filter, though. All the trucks (Cummins/Allison) I have owned have had drain plugs, along with all the upscale cars...

Mopar did not... AMC did not... no of my 6 autom. trucks/cars have.

But.. is this still theh glowplug thread?

Do i understand this correctyl? First 4-8 seconds after tun the "Key" on 24V on the glow plugs.
And after this, there is a "after glow cycle"? How is it structured?
What should I read on the meter when everything is working correctly?

The permanently 24V if defective. Are they then always on all 8 glowplugs or only on individuals.

 

[blutow]

Bottom line, there is no way to change the filter without making a mess unless you have a drain plug to lower the fluid level before lowering the pan.

I bought one of these extractors years ago and they work amazingly well. Even for vehicles that are easy to drain from below with a plug, I often use the extractor because it's such a clean and easy process. You can also use it to quickly empty a power steering or hydraulic fluid reservoir with no mess.

 

[diesel_dave]

Mopar did not... AMC did not... no of my 6 autom. trucks/cars have.

But.. is this still theh glowplug thread?

Do i understand this correctyl? First 4-8 seconds after tun the "Key" on 24V on the glow plugs.
And after this, there is a "after glow cycle"? How is it structured?
What should I read on the meter when everything is working correctly?

The permanently 24V if defective. Are they then always on all 8 glowplugs or only on individuals.

Afterglow on my yellow label box runs the plugs for one second pulses for 2 minutes after cold start. You should see your multimeter pinging from 0 to ~28v if afterglow is running. I can also hear an audible change in engine pitch every time the glow plugs are energized on my truck.

 

[MarkM]

A very quick little video I made of the operation with my box.

Mark

 

[diesel_dave]

A very quick little video I made of the operation with my box.

Mark

Exactly the same as mine. I'm not sure I like the afterglow. It can't be helping the glow plugs to have a long life.