1994 M1123 won’t start. Please help!

[MrLucky7137]

Hello everyone thank you for adding me. My M1123 cranks just fine but won’t start. I have 2 good batteries, I’ve replaced all of the glow plugs, cleaned and replaced the fuel filter and the air filter, I did try a little bit of either just to see if it would fire and it sure wanted to. The fuel injection pump is only getting 4.9 volts to the A wire on top. I have cleaned and tightened every battery connection and ground I can find. Thank you

 

[Mogman]

You need 24V to wire 54A, check the voltage on 5A at the gen. with the switch in run there should be 24V there, if not it may be a bad EESS

 

[MrLucky7137]

You need 24V to wire 54A, check the voltage on 5A at the gen. with the switch in run there should be 24V there, if not it may be a bad EESS

I’m sorry this is my first humvee and I’m still learning. Can you tell me which lead is 5A please.

 

[Mogman]

Every wire has an aluminum tag on it, the one going to the fuel solenoid on the IP is 54A, the one that excites the alternator is 5A, just look for the tag numbers.

 

[Mogman]

This would be a good time to welcome you to SS, and suggest it is a good idea download and learn how to use the TMs they are all here to download for free.
There are allot of folk's here that are willing and able to jump in and help but the sooner you come up to speed on the TMs the easier it will be for you to understand your HMMWV.

 

[MrLucky7137]

Every wire has an aluminum tag on it, the one going to the fuel solenoid on the IP is 54A, the one that excites the alternator is 5A, just look for the tag numbers.

yeah my humvee doesn’t have tag numbers not anymore anyway lol.

 

[Mogman]

I have never seen more than 1 or 2 missing tags on ANY military vehicle I have looked at, look again they are small aluminum tags, looks like something that would be on a pigeons leg for identification, I am looking for a pic but I will bet they are there.

 

[Mogman]

Something like this..

Every wire on a HMMWV has a tag, with the possible exception of added accessories

 

[Milcommoguy]

Quick question. Do you have a key ignition or military switch. Using the meter, have you measure the battery voltage and report back.

Had to ask, CAMO

 

[MarkM]

You really should not use ether on the Hmmwv motors. It will work but you will be playing with fire.

Mark

 

[MrLucky7137]

Quick question. Do you have a key ignition or military switch. Using the meter, have you measure the battery voltage and report back.

Had to ask, CAMO

it has the original military switch. Good voltage im getting over 24 volts. Thanks

 

[MrLucky7137]

Something like this..
View attachment 881712
Every wire on a HMMWV has a tag, with the possible exception of added accessories

That makes sense. I did find some but they are quite unreadable.

 

[MrLucky7137]

You really should not use ether on the Hmmwv motors. It will work but you will be playing with fire.

Mark

i was waiting for this one lol. I only did it to test the ignition system. One quick spray and it tried to start

 

[MrLucky7137]

Something like this..
View attachment 881712
Every wire on a HMMWV has a tag, with the possible exception of added accessories

any chance you have some type of diagram or something to go by for me to locate 5A?

 

[Milcommoguy]

This link should help. Pages 1 and scroll down and some Scotch Tape >https://hmmwvsystems.com/hmmwv-wiring/

5A is the "SENSE" lead from the control box to the alternator. 24 Volts in the RUN position. Some might call it the exciter or field.

Sticky subject. And there's the TM's too, CAMO

 

[Mogman]

A diesel has no ignition system, it fires on compression and fuel, work on getting fuel to the injectors first.
The tags are readable unless it has been submerged in salt water for a long time, if it is in such bad shape you cannot read the wire tag numbers you are in deep do do...
Wire 5a is at the gen as I said before, big kinda round thing on the drivers side of the engine.
Try carefully cleaning the wire tags with a tooth brush and a little WD40, the numbers are there...

 

[jkcondrey]

Do you have fuel coming up? While cranking open the fuel filter drain located on the driver fender well. It should flow pretty good with a working pump. Follow the fuel hose leaving the bottom of the filter to its terminus. Should have a little elbow valve on it.

 

[MrLucky7137]

A diesel has no ignition system, it fires on compression and fuel, work on getting fuel to the injectors first.
The tags are readable unless it has been submerged in salt water for a long time, if it is in such bad shape you cannot read the wire tag numbers you are in deep do do...
Wire 5a is at the gen as I said before, big kinda round thing on the drivers side of the engine.
Try carefully cleaning the wire tags with a tooth brush and a little WD40, the numbers are there...

you are correct. I was referring to the glow plugs at least I know they are getting hot

 

[MrLucky7137]

Do you have fuel coming up? While cranking open the fuel filter drain located on the driver fender well. It should flow pretty good with a working pump. Follow the fuel hose leaving the bottom of the filter to its terminus. Should have a little elbow valve on it.

i do have fuel coming from the pump on the motor for sure. I’m positive im getting fuel to the injection pump just not to the injectors.

 

[Mogman]

you are correct. I was referring to the glow plugs at least I know they are getting hot

No you do not, that engine will fire off of ether without the glow plugs, you said you replaced the glow plugs, a simple volt meter test will tell you if you arre getting power to the glow plugs and if the PCB is cycling them correctly.