M1123 Glowplug issues

[Cluongo]

Hi guys, im just looking for some guidance with an issue I have with my 99' M1123 6.5l NA glowplug system. The wait light functions like normal but i still get a hard start/heavy white smoke on cold start with cold weather. Last winter I replaced all 8 glowplugs with a fresh set when the hard start issue began. It was better for awhile but now its back to starting hard. Last week while idling it spit out the center probe of cyl 8 glow plug. Obviously i have a bigger issue with the system if its frying glowplugs and spitting them out of the block. Ill attach pics of the controller box. Any ideas of how to diagnose what the heck is going on with this thing?

 

[Cluongo]

 

[MarkM]

First question. What size is the glow plug nut? 3/8" or 10mm?

 

[Cluongo]

10mm

 

[Cluongo]

First question. What size is the glow plug nut? 3/8" or 10mm?

10mm

 

[MarkM]

Those are extra cheap chicom trash that should never be used. Change out the glow plugs with Wellman plugs. Only way to go with the HMMWV. Sorry you wasted your time with junk. Hopefully the old ones come out easy and use copper never seize on the threads.

They must be 3/8" to not be chicom.

After you install the new plug please check out the operation by getting the voltage off the pass rear plug and test the system to make absolutely sure they don't stay energized for more than around seven seconds or you risk frying them. Wish I had as my relay in the box was stuck closed and I cooked my plugs. Made the little vid below.

Good luck

Mark

 

[Retiredwarhorses]

Get rid of that old Narton box and TSU, buy and install an S3 EESS with new TSU, change out all your plugs.
Im certain your exsisting box is not turning off the 24v after 9 second, to verify ….use a a voltmeter on a glow plug boot, after the GP light expires, you should not get a “constant“ flow of 24v, it should pulse for 2 mins on and off, if it’s solid? You have your culprit.
Lastl, stop buying cheap Chinese glow plugs….I stock OEM, as well as boxes, also only buy from distributors like HPG, MAC, Kascar and verified sellers.

 

[Cluongo]

Those are extra cheap chicom trash that should never be used. Change out the glow plugs with Wellman plugs. Only way to go with the HMMWV. Sorry you wasted your time with junk. Hopefully the old ones come out easy and use copper never seize on the threads.

They must be 3/8" to not be chicom.

After you install the new plug please check out the operation by getting the voltage off the pass rear plug and test the system to make absolutely sure they don't stay energized for more than around seven seconds or you risk frying them. Wish I had as my relay in the box was stuck closed and I cooked my plugs. Made the little vid below.

Good luck

Mark

Thanks for the info, ill swap in a new set and test the voltage to make sure its not getting constant voltage. Is a set of plugs from midwest military equipment quality stuff?

 

[Coug]

You should test the output before trying to put in a new set.
If you put in the new set then test, if it's failed then it won't turn off and you might fry the new set you are using to test.

 

[Cluongo]

Get rid of that old Narton box and TSU, buy and install an S3 EESS with new TSU, change out all your plugs.
Im certain your exsisting box is not turning off the 24v after 9 second, to verify ….use a a voltmeter on a glow plug boot, after the GP light expires, you should not get a “constant“ flow of 24v, it should pulse for 2 mins on and off, if it’s solid? You have your culprit.
Lastl, stop buying cheap Chinese glow plugs….I stock OEM, as well as boxes, also only buy from distributors like HPG, MAC, Kascar and verified sellers.

How much do you get for a S3 box, 8 plugs and a tsu?

 

[Cluongo]

I threw in a set of wellman glowplugs, pulled the nartron box and installed a push button to essentially jump the solenoid and give 24v to the glowplugs while the button is pushed. Works like a charm and the truck cold starts with no problem. Only issue is the truck isnt charging. Im guessing it has something to do with the alt sense wire in the eess box.. any ideas? Does the alt sense wire need ignition power or constant power?

 

[TOBASH]

Diagrams and legends will explain which terminal does what.

How to bypass PCB? I am aware some HMMWV owners have done it. TOBASH

I'm not trying to speak sacrilege here, and I don't want to precipitate a war of words. :shock: How might I build a manual control box? My 24Volt Landcruiser just uses a glow wire to show glow plugs are ready, and then she just starts right up with the twist of a key. Civilian 6.2 Diesel...

www.steelsoldiers.com

 

[Mogman]

The alt sense needs switched run power, also check the heater fan, on the same circuit as the alt.