HMMWV Glowplug Diagnosis

[rmgill]

So a neighbor has a friend who has one of the USMC/FMC batch M998s. He brought it over for a party Saturday night and left the ingition on overnight. Connected to a slave cable, the engine would turn over but never start. Smoke told me it was getting fuel.

I've never diagnosted a HMMWV before but I poked around and noted the following:

1. 3 checked glowplugs were showing open circuit both installed and removed from the engine.
2. The 3 pulled plugs were wet with fuel.
3. The Wait light never lit while trying to start it the next day.
4. He has a KDS smart controller.

I read the Glowplug gospel thread and noted details there.

It's a new vehicle to the owner and he had no manuals with it nor did he have any BII or spares. So, he's ordering a set of glowplugs (the better types) and a replacement/spare controller unit and the ground harness. It has the KDS Smart Controller so we should be good there. Extra stuff will be set aside as spares.

When parts are on site, I'll pull each glowplug and replace and then bench test the removed units just to see what the deal is. Any good ones will then be checked. I'll be working from the manual of course.

The little flat relay units, do those fail regularly? Perhaps another part to order and have on hand?

The batteries are getting a full deep charge with a smart charger unit that I own so they'll be good to go when we get to working on this Tuesday or wednesday.

We'll probably be doing some other remedial repairs on this truck (like the non functional parking brake).

Anyone have any nuggets of advice?

 

[rmgill]

Also, to add, the I've made sure the cannon connectors are clean and corrosion free during my work sunday. They were cleaned/lubed with CRC 2-26.

Additionally, the truck will be getting a battery disconnect to add some insurance against this and provide some security.

 

[emmado22]

i carry an extra PCB box with me all the time. It is one part, that if/when it fails, no NAPA, ORielys, Autozone, or any other parts store carries, nor can get.

 

[rmgill]

Pretty much my point to the owner if the PCB does end up being ok. The money spent means a part swap in the field vs a tow and substantial downtime where he may not want to be for hours. He agrees so isn't quibbling over ordering the controller box.

 

[Retiredwarhorses]

Ok....is it PCB or an EESS?

This issue has been beaten to death, its in the sticky Ted created....I know cuz I wrote.

but let me be clear....if you DO have an old PCB "protective control box" this will use a "GPC" glow plug controller....this is the old prone to fail system. It has been replaced with the EESS and TSU, these 2 units generally come in the same box, the TSU replaces the "GPC" in the water crossover...the TSU ONLY sends temperature to the EESS box....UNLIKE the Old GPC glow plug controller which sensed temperature and lit up the glow plugs....this system was highly prone to failure.
the glowplug controller feature is now in the EESS box under the dash.

So which box do you have under the dash? Maybe post a pic?

and yes...do the grnd harness.....and go read:

http://www.steelsoldiers.com/showthread.php?90657-LEO-FD-HMMWV-Check-List/page3

 

[Retiredwarhorses]

Oh......make sure the ground on the battery is disconnected....or you WILL fry your boxes.

 

[rmgill]

I thought I was clear.

The variation in units is greater than it seems based on initial checks. The KDS unit does have the extra diag port on it, but I think it's a green label unit and not a yellow label unit.

Why the heck do the units fry when you disconnect power from them? Seems a design fault.

 

[Retiredwarhorses]

You said green label...the boxes are black with yellow or green labels...well they used to be, now the box is green.
do you have the correct temp sending unit in the water crossover? It comes with S3 EESS box you state you have in the truck.
and I have never had a box fry from disconnecting the power from it....the S3 EESS is much more fault tolerant then the early yellow and green label units.

 

[rmgill]

The owner had time today and brought the parts over. Glow plug swap and installation of the aux ground harness yielded no start and nothing for power. Check the cannon connectors that had been left unplugged and we get the wait light, let it cycle, then start and vroom! A faster start than it normally used to do. Every single one of the old glow plugs was showing open circuit. I'm not sure how it was starting before unless some were bad. That right rear plug is a pain, but not impossible for my long arm.

 

[jwaller]

the right side is done from the inside of the truck. But congrats on getting it Fixed. I had many go issues with my truck the first couple years I had it.

 

[rmgill]

Hah, I was actually able to just reach the right rear unit from the engine bay. I had heard from another HMMWV owner how hard those were to reach. Working on British armor has helped me hone some contortionist skills.

 

[Bradyrw625]

When the PCB went bad we used to use a paperclip (wrapped in electrical tape) and jump it through the STE/ICE - diagnostic connection. Right above the gear selector. I believe it was pin S and T. I'm sure there are guys around who can confirm the pin letters. This also works on 5 tons. It's located under the dash on the passenger side.

 

[Dsc45shooter]

Can someone post a picture of and describe where this notorious cannon plug that corrodes is located?