ANOTHER HMMWV GLOW PLUG PROBLEM!

decodeme2 · Jan 21, 2008

Hey Guys,
1987 M1044, 6.2...
Replaced the controler, replaced the engine sensor, even replaced the engine wireing harrness. Turn the knob, glow light lights up, then goes out..The light stays on longer when colder.., If I try and start it, nothing, If i crank the crap out of it , it will start. Check the glow pugs, with a ohm meter and its weird..I get 16volts for 1 sec, then 2 volts, then 8 volts, then nothing. Each timre I try it I get different voltage readings.. Even when the light is on I get no voltage. Maybe I got a bad controler?..Is the controler the black box under the dash?..Is there something else Im missed replaceing?..Yes, I put new Glow plugs in..
Thanks in Advance..

Kevin..

TedG · Jan 22, 2008

Cevon,

Do you have a ground harness installed? If not, buy one immediately from a vendor (kascar) or make your own. The engine block needs to be bonded to the grounds of the: dash stud, controller box, generator, starter.

Also, go to the manual section of this site and download the necessary manuals for extremely useful information. Else, buy the manuals on ebay.

Regards,

blackdog · Jan 22, 2008

Hi, does your glow plug light go on for like a fraction of a second and then off immediately? If you don't have a green or yellow label PCB I would replace the GPC because I was having the same problems...

decodeme2 · Jan 22, 2008

I will double chaeck the grounding of the engine, I will tempory hook up some jumper cables from the battary ground to the engine block, and to the dash bolt on the GPC..To see if it helps. The glow light stays on for 5 secs in 60 degree weather..(heated garage). I will check the label on myme...
I will check the ground harness..I thought the engine harness was also a ground harness..The engine was just installed, maybe they forgot a wire or 2...thanks for all the info!..Whats a "PCB"?...
Kevin...

sheriffsam6 · Nov 11, 2008

With what I have seen it is probably the PCB box, and along with that the long cranking is due to a check valve in the fuel filter assy that goes bad. Check voltage between 54A and I think (c) port going into PCB if voltage less than 2 V probably problem

actionpaintball · Nov 11, 2008

X2 on the additional grounding harness. You should have at least one running from battery ground to engine block, alternator bracket and PCB mount. I have had trucks blow through glow plugs with good new green KDS boxes because the system was not grounded correctly. Before you do anything else-go through and install good aux ground harness with minimum 12 gauge wire.

jwaller · Nov 11, 2008

also check the ohm's of each glow plug. should be at least 1ohm. if not then you have at least a bad one. I have about 1 a month that needs to be replaced.

emmado22 · Nov 11, 2008

I have had great sucess with KASCAR's non swelling glowplugs in my M998.

jwaller · Nov 11, 2008

emmado22 said:
I have had great sucess with KASCAR's non swelling glowplugs in my M998.

ya but arent they super expensive?

readyman · Nov 13, 2008

From my experience...
HMMWV - High Maintenance Money Wasting Vehicle

hummer4x4guy · Nov 24, 2008

Ya get what ya pay for. I 2nd the non swelling glow plugs. There is also a guy on ebay that sells pretty much the same style plug for the humvee and they are non swelling and one year warranty. Got an extra 8 sitting around here waiting for me to use em..
Joel (still alive n kicking) humvee price is down to 29,900 if anyones interested...

gem1410 · Jan 24, 2012

Kevin---what did you do to get the humvee glow plugs working--I am working on mine and have the same problem you had back in 2007---George

3ID ARMY BRAT · Jan 24, 2012

I know this has nothing to do with what the thread is about. But a good friend of mine whats to get a M988 HMMWV. So I'm Asking where to find One. If any one can help me whit this I would be much appreciated.

DEA AK · Oct 19, 2023

TedG said:
Cevon,

Do you have a ground harness installed? If not, buy one immediately from a vendor (kascar) or make your own. The engine block needs to be bonded to the grounds of the: dash stud, controller box, generator, starter.

Also, go to the manual section of this site and download the necessary manuals for extremely useful information. Else, buy the manuals on ebay.

Regards,

This ground harness that you mentioned… is that not already installed on the HMMWV?

Is it in the battery box? How do I know if I am good to go with mine? I had my glow plugs burn out - is that a ground problem?

I have wires on my NEG shunt, is that the grounding harness you mentioned or do I need more?

I am not a mechanic so all this stuff is new to me.

Thanks,
David

AAVP7 · Oct 19, 2023

That thread is more than 10 years old. At that time, an extra grounding harness was sometimes sold as the ultimate cure for all electrical problems on a Humvee.

However, the factory wiring harness already contains ground wires. There are very, very few electrical items on a Humvee that use the body as ground. All important items have ground connections in the stock wire loom.

So, IF your factory grounds are nice and tight, there´s no need for an extra grounding harness. If they are not tight and clean, well, instead of buying an extra grounding harness, why not just clean those ground connections ?

The one ground connection that seems to cause most trouble is the body stud hidden behind the heater controls. Remove the doghouse, remove the instrument panel then you can inspect and clean the wires attached to that grounding point.

Glow plugs in my view mostly burn out because of a defective control box that doesn´t stop afterglow. Always watch you voltmeter during afterglow. During afterglow, the needle will either pulsate or stay in the yellow for a few seconds. If the needle doesn´t go to green after a few minutes at the latest, you either have permanent afterglow, or a defective alternator.

Some users recommend to use only the latest S3 control box, others use manual afterglow control. Google Camoteksystems for a box with manual afterglow.

TOBASH · Oct 19, 2023

AAVP7 said:
That thread is more than 10 years old. At that time, an extra grounding harness was sometimes sold as the ultimate cure for all electrical problems on a Humvee.

However, the factory wiring harness already contains ground wires. There are very, very few electrical items on a Humvee that use the body as ground. All important items have ground connections in the stock wire loom.

So, IF your factory grounds are nice and tight, there´s no need for an extra grounding harness. If they are not tight and clean, well, instead of buying an extra grounding harness, why not just clean those ground connections ?

The one ground connection that seems to cause most trouble is the body stud hidden behind the heater controls. Remove the doghouse, remove the instrument panel then you can inspect and clean the wires attached to that grounding point.

Glow plugs in my view mostly burn out because of a defective control box that doesn´t stop afterglow. Always watch you voltmeter during afterglow. During afterglow, the needle will either pulsate or stay in the yellow for a few seconds. If the needle doesn´t go to green after a few minutes at the latest, you either have permanent afterglow, or a defective alternator.

Some users recommend to use only the latest S3 control box, others use manual afterglow control. Google Camoteksystems for a box with manual afterglow.

Search this forum keywords Tobash and bypass and learn how to easily build your own box. Won’t cost a lot.

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

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

DEA AK · Oct 19, 2023

AAVP7 said:
That thread is more than 10 years old. At that time, an extra grounding harness was sometimes sold as the ultimate cure for all electrical problems on a Humvee.

However, the factory wiring harness already contains ground wires. There are very, very few electrical items on a Humvee that use the body as ground. All important items have ground connections in the stock wire loom.

So, IF your factory grounds are nice and tight, there´s no need for an extra grounding harness. If they are not tight and clean, well, instead of buying an extra grounding harness, why not just clean those ground connections ?

The one ground connection that seems to cause most trouble is the body stud hidden behind the heater controls. Remove the doghouse, remove the instrument panel then you can inspect and clean the wires attached to that grounding point.

Glow plugs in my view mostly burn out because of a defective control box that doesn´t stop afterglow. Always watch you voltmeter during afterglow. During afterglow, the needle will either pulsate or stay in the yellow for a few seconds. If the needle doesn´t go to green after a few minutes at the latest, you either have permanent afterglow, or a defective alternator.

Some users recommend to use only the latest S3 control box, others use manual afterglow control. Google Camoteksystems for a box with manual afterglow.

Great info, thank you very much.

ANOTHER HMMWV GLOW PLUG PROBLEM!

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decodeme2

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TedG

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blackdog

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decodeme2

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sheriffsam6

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actionpaintball

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jwaller

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emmado22

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jwaller

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readyman

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hummer4x4guy

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gem1410

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3ID ARMY BRAT

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DEA AK

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AAVP7

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TOBASH

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

DEA AK

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