Hard Start, white smoke despite good glowplugs and 24v at each lead??

[Kevin Donahue]

Really at a loss with this one.

Tested all the electrical stuff and it looks perfect yet my Humvee is very difficult to start. Doesn't seem temperature dependent.

So more than likely fuel issue. What tests do you recommend I perform next? What's common failure points in the fuel system?

Runs and drives perfect once started btw.
2003 M1123 6.5

 

[jkcondrey]

If your truck sat for awhile at auction, replace the mechanical fuel pump. If you haven't changed the filters do that as well, and some fuel system cleaner. If this doesn't clean it up, start working through the glow plugs. Just my history with them.

 

[diesel dave]

White smoke tells me 2 things;
It’s getting fuel
Bad glow plug or plugs.
Are you sure you checked all 8?
In cold weather it only takes 1 bad plug to cause hard starting,especially on a worn engine.

 

[Kevin Donahue]

White smoke tells me 2 things;
It’s getting fuel
Bad glow plug or plugs.
Are you sure you checked all 8?
In cold weather it only takes 1 bad plug to cause hard starting,especially on a worn engine.

Yep, all 8 ohmed out at under 7 and all 8 leads are supplying ample power. Not to mention I just changed them all about a week ago thinking the same thing. I am wondering if the cold advance solenoid has something to do with this. White smoke to me definitely indicated its getting good fuel too honestly but I am stumped.

 

[Kevin Donahue]

If your truck sat for awhile at auction, replace the mechanical fuel pump. If you haven't changed the filters do that as well, and some fuel system cleaner. If this doesn't clean it up, start working through the glow plugs. Just my history with them.

Thanks will do.

 

[Kevin Donahue]

Another update:

Started checking over other suspect electrical components. Thought maybe the cold advance solenoid could be bad. Seems as if the switch is doing its job and supplying 24v when engine is cold according to my multimeter, also clear that the solenoid itself is getting power.

I don't really know how to verify the solenoid is doing anything but I guess the obvious way would be to unplug it and plug it back in with the truck idling. Probably will give that a shot tomorrow. I tried firing truck up with the solenoid unplugged already tonight and no noticeable difference what so ever so I think I may be on to something.

When I jumper the switch I do hear a faint "click" but it doesn't sound like its coming from the solenoid or anywhere near the injection pump. Sounds lower and driver side of the engine maybe.

What do I need to do if that solenoid is bad? Hopefully not have someone rebuild the IP lol....

 

[Deals7]

I'm going through the exact same thing on an M1123 I bought from GP. Was told it was driven onto the trailer but wouldn't start when arrived. Was low on fuel and batteries were low so I assumed it wasn't getting fuel the whole time I was cranking it. Finally out of desperation I ran a strap to the starter switch and stuck a Leaf Blower in the Fuel Tank opening. Started to sputter and later, after charging the batteries again sputtered and finally started. Had to have really highly charged batteries but it started, drove around and then shut it off. Restarting was the same problem but finally started, third time no start but small sputtering.

It seems to help when the gas peddle is being applied FOR SURE. But seems like something is holding it back. Lots of white smoke while turning over and once started a large thick plume of white smoke slow to dissipate. Going to try the leaf blower again and a few other tricks I've read on here and on the Youtube site of the Jerry Rig guy, who didn't actually Jerry Rig, he gave up and pulled the motor....

Any tips welcome. This had 80 miles from GP and appears to have about that much use aside from just the odometer. Thanks, Scott-

 

[jkcondrey]

Sounds like glow plugs not lighting and fuel supply. Didn't see if you changed your filters too.

 

[Coug]

How do you know that the glow plugs are good? Have you put the multimeter on every one and checked for resistance, or did you just put in new ones and assume they are still good?
Plus, if you have to pressurize the tank to get it to run, then something not right there either. Commonly it's a bad lift pump or something plugged, but could also be a pinhole leak in the suction line letting air in and fuel to drain back down when it sits.

 

[papakb]

In cold weather the cold start solenoid in the IP opens to inject a little extra fuel to start the truck. What you may be seeing is that extra fuel burning off, especially if it goes away after a couple minutes.

 

[Deals7]

Thanks Coug, I'm inclined to leave all components that should not have failed in storage and just focus on consumables, such as the fuel suction line or "lift pump" but I'm not sure what the lift pump is. Then once the smoke comes out I'm thinking the blow-by I bought this with, is anti freeze leaking in but if that was the case it seems to completely stop after the motor starts running. Maybe there isn't enough of a head-gasket leak to allow that much coolant into the engine once it starts.

I have not checked anything including the plugs, and am hesitant to do so, as I have the most basic pathetic tools. I changed the tire and the run flat ring with, among other things a crescent wrench because none of my sockets would fit. So for me to fix anything is nearly the same effort as whomever created that which I'd be fixing. I'm not the one for that, but I have two of these M1123's and really just want to will them to run.

I saw a video of a Drain Valve in front of the driver side area, thought I'd try to see if it's leaking, causing what you suggested above, the fuel falling back to the tank and leaving the line empty. Also need to check a couple other things but your idea of the air in the line seems to make most sense.

I bought some Diesel Fuel fix-it stuff, Hot Shot Extreme I'll try, I'll also try some Starting Fluid in the Air Filter and will try adding some coolant Head Gasket Fix it Fluid in the hopes of fixing both things at once. I bought one that does NOT have Silicone Glass.......

Anyone know what that giant red button is behind the battery compartment on the passenger side?

Also, there is a huge thick cable that was cut-ff and left not covered next to the passenger side, like a power outlet. Thinking it could have just a slight contact within the 3 wire housing causing it to not fire cleanly.... I'll post a pic here if I can.

Thanks,

Scott-

 

[Deals7]

Yrd

 

[Deals7]

This is the red button behind the battery compartment, anyone know what it does??

 

[Action]

This is the red button behind the battery compartment, anyone know what it does??

It resets the trans circuit breaker, if it trips.
I would not use starter fluid in a diesel motor.

 

[Deals7]

It resets the trans circuit breaker, if it trips.
I would not use starter fluid in a diesel motor.

Thanks! Guess I don't need that one for now.

I* did get it running again, just kept pumping the peddle and finally roared to life. The feeling of getting it running after being a lawn ornament is so amazing..... Dang!

Video:

Still running in the front yard, hate to turn it off...... Not sure what to do. At least it's charging the batteries....

 

[Coug]

*snip*
I'll also try some Starting Fluid in the Air Filter
*snip*

These are a design that does NOT like to have starting fluid used on it. As in, you can damage the cylinder head/precombustion chamber and cause some serious issues that will cost a decent chunk of money to repair, that is entirely preventable by NOT using starting fluid.

Once again, DO NOT USE STARTING FLUID!!!

Not trying to be a jerk, just trying to get your attention and get the point across.

 

[Coug]

So it's hard to give good advice, when you are giving mixed information.
Not trying to be rude, but there is a big difference between "my glow plugs are good" and "I have not checked them because of inadequate tools, but the truck hasn't done anything in a while so I assume they are good."

All you need to do to check the glow plugs is unplug the wire to them, and use a multimeter set to continuity. If it says 0, they are shorted out. If it shows open, they are burned up/open circuit. Not that in depth or difficult. I believe the correct reading for them is around 1 ohm, but might be wrong. If so hopefully someone can provide the correct info. I'd not worry quite as much on the actual number provided they are all giving similar readings that aren't 0 or infinity.

White smoke is a sign of unburned fuel. Typical cause of unburned fuel at startup is bad glow plugs.
Until you actually test them, don't just assume they are good because the truck has been sitting and rarely ever started. If the control box fails, it can send voltage to the glow plugs continuously, until they burn up. Some people found out the hard way when their brand new glow plugs don't work on the second crank.

So once again, making assumptions that things are working properly, without testing them, means we can't give you accurate assistance as you aren't giving us accurate data to work with.