Still having starting issues. Glow plugs not working. Changed everything I can think of PLease Help

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MarkM

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Still can't easily start the truck and finally figured out the glow plugs are not getting power. Have two spare take out boxes and no power to the plugs. New harness NEW!!! HMMWV engine harness P/N: --------. New plugs. New batteries. Shows no voltage at the plugs. Wait light comes on for around seven seconds as goes out. Flashes once when starting after engine is hot. Any ideas at all where to go next? Has to be something dumb. . Everything works as it should once started but needs to be warm out. Thank you.

Had listed wrong part number and sent the inquiry in the wrong direction. Please see my post below for the correct part numbers. Very sorry for the screw up.

Mark
 
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I see you’ve had some recent issues, and have swapped out a bunch, but don’t know the current configuration of PCB’s. The glow plug controller seems to be partially working, as it’s sensing temp, but have you Ohmd out all the leads from it? It’s something easy, but you need to be methodical about it. I would start with the Glow plug controller, then it’s harness, then pcb, then glow plug harness. There is a great procedure in the HMMWV troubleshooting guide starting on 12-4, but the guts are on 12-6. It’s that or an alternator, but feels to me like one of those 3, and you’ve replaced one. But electricity doesn’t lie, do the ohms and continuity as laid out, and I think the gremlin will surface... I am assuming things like PCB and controller mismatches is already done. And remember to disconnect the battery before starting..

Good luck, report back.
 

Milcommoguy

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How does the ENGINE HARNESS connector look. Check the pins REAL carefully. May even have to open it up to see what's going on. VOM with sharp probe to poke into the insulation at the plug can work to. PIN "D" is the one of interest. Remember it could be cycling on and off, so might need a helper on the RUN switch. No 24 Volts...funky "DUM " box.

Can be lots of current flowing thur that 1 pin, Leter "D"... which is a little small to handle 100 Amps IMO.

Corrosion and crud, burned, bent or busted, CAMO
 
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TOBASH

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Like Cam O says... pin D on the engine sided plug on the PCB is the pin that gets hot and sends power to the glow plugs. If it is not working and never powers up to 24 Volts, you have your answer.
 

papakb

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I recently worked with a friend here in California and when we opened up the control box we found the cheap ChiCom relay they used for the glow plug circuit had fried. Checking online we found them for $1.87. What does that tell you about the quality of the relay? Panasonic makes an identical relay that's $9.00 from Digikey Electronnics that we hope will fix the issue. Like what's already been mentioned here, check for voltage on the engine harness connector. If it isn't there, disconnect the negative lead from your batteries and pull the control box, open it up and take a look inside. Since the wait light is working you have a good chance of being able to repair it if it's just another garbage Chinese relay!

With the prices these manufacturers charge the government for their products it's almost criminal that they would use substandard parts inside, especially when lives depend on their products working! Let's go back to when everything sold to the government had to be made in the USA.
 

Retiredwarhorses

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Still can't easily start the truck and finally figured out the glow plugs are not getting power. Have two spare take out boxes and no power to the plugs. New harness NEW!!! HMMWV Glow Plug Distribution Box Interface Harness P/N: 12379865. New plugs. New batteries. Shows no voltage at the plugs. Wait light comes on for around seven seconds as goes out. Flashes once when starting after engine is hot. Any ideas at all where to go next? Has to be something dumb. . Everything works as it should once started but needs to be warm out. Thank you.

Mark
that part number is for a LAU industry box...the absolute worst.
I think most folks think you changed the engine harness, that is where the GP connections are, that harness you have spares the engine harness GP leads and uses a separate harness that plugs into the LAU box...you might want to post some pics.
trucks were starting on there own with the LAU box and burning in the motorpool.
 

TOBASH

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So Cam O and I had it all wrong.

You have a separate plug for your glow plugs. Don't bother checking pin D.

Most boxes activate the glow plugs via a one plug engine harness strategy. On the more standard units, the D pin controls the current for the glow plugs.

You need to get rid of that box in a hurry, as it known to cause issues.

Best,

T
 

papakb

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Steve is 100% correct on this! If you have one of the LAU boxes installed remove it immediately! They are a fire hazard. They were known to randomly crank trucks until the batteries died or they caught fire. Lau did a software upgrade for free but by then they were all branded 666!
 

Milcommoguy

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I did read that about the changing of the harness and though that was a quick swap. Wasn't thinking (Me real BAD) that someone would still running one. So sorry about the BAD info.

So one quickie test is to check for voltage there on the glow plug feeder connector on the box with helper cycleing the RUN switch. Quickie #2 check each of the glow plugs at each of the pins of the engine harness cable, one at a time looking for a very low resistance of 1.5 to 5 Ohms +/- of each pin to a good ground. Pin with no resistance fried plug. (basically go with that)

Good plugs and no voltage showing up... Quickie try and start. Could apply 24 Volt battery to ALL the pins same time, 6 seconds on, 6 off, 6 on, 6 off and attempt to start. Question how warm is it there?

More pictures and description of what one has and the goings on is most helpful in a logical guessing process to help out.

AND as stated............ TIME to ditch the box.

Rolled the dice and scratched... AGAIN, CAMO is a BAD BAD boy.
 
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MarkM

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Thanks for the replies guys.

I worded my post poorly and put in the wrong part number. Let's start again. The engine harness that is now in the truck is part number 12339350 (See pic)

New glow plugs Part number 2920011883863

I have a yellow stripe glow plug sensor in the intake manifold part number CR-2696A (see pic) .

The PCB box that is currently in the truck is a yellow label Part 32498 (see pic)

Installed a grounding kit.

Two new Optima Red Top batteries using adaptor trays.

Glow plugs are not working. No power to the glow plugs. Wait light works as it should (about 7 sec on with starting when cold)

Again sorry for the misleading post and I sincerely appreciate all the help. Please respond.

Mark

20190801_172137.jpg

s-l500 (1).jpg

hmmwv-6-2l-engine-wiring-harness-12339350-13.jpg
 
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TOBASH

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Is that KDS glow plug sensor compatible with that Nartron box? Not all boxes can work with all sensors.

There is a guide somewhere.

Best,

T
 

MarkM

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I just used the pic I found for reference as mine is a older unit and I tried another used one I had same issue.

Mark
 

TOBASH

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When you post pictures, we use those pictures as information. You need to post exactly which sensor you are using otherwise there is an assumption that you are using the incorrect sensor.

[EDIT - I Reread my post... I don’t mean to sound harsh. Just trying to help by getting accurate information. ]
 
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MarkM

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LOL understood I will snap a pic of what is in there. It came off the same running truck that the PCB bax came from.

Mark
 

Milcommoguy

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Oh, I see said the blind man. Nice pictures worth a thousand words. Go back through some of the previous posts. I feel they will apply this go around.
HumV not always as easy as "plug and play"

There's these little gremlins known to hang out under the hood. Going to need "Buster Tool Kit" and the guys here to catch them in this virtual world..

BTK list. Eyes,ears and a good sniffer. VOM or test light. (see 'CAMO can, you can too... post and NO winners) and some of the basic test. I point to this easy read > https://hummerhuren.files.wordpress.com/2013/01/hmmwv_test-diagnostics.pdf

You can jump right in... BUT clear out each test and don't catch yourself going in circles. Set the trap on those little buggers.

Say got fuel..SAY IT.... GOT FUEL ? good pressure to IP, Check.

Crack one of the injector lines, got fuel, Check. Next voltage to IP solenoid with good clicking action, Check. Voltage to glow plug, Check.(The PIN ("D" thing.)
Resistance of glow plugs, Check. These tests will provide data to narrow down the little buggers.

Keep batteries charged up. and when cranking give it time to cool the starter down. (I just saw a video here. It seemed to me to be a bit long on the run time IMO, may needed to be purged ??)

We all feel your frustration. Learning lesson together, CAMO

Boy, I sure hope I read this right this time. :rolleyes:
 

papakb

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Your post starts with "still won't start". When was the last time it did?

The HMMWV has an interesting characteristic where when the tank is full the IP can get the truck started all by itself, meaning if the truck has a bad mechanical fuel pump it will still start and run. When the tank gets low the IP can't pull enough fuel to get it going. Something to keep in the back of your head.

Also, what's the outdoor temperature where you are? Above a certain point the GPC or temp sensor tells the control box it doesn't need to power the glow plugs. Is this the situation your currently experiencing?
 

MarkM

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As long as the temp outside is 65 or above she starts with no issue it's below that temp I need to glow plugs. Drove the truck today without issue as the temp was 80.


Mark
 
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