hmmwv white smoke

[Mogman]

I am just trying g to figure if this could be from sitting so long or if it has happened after you drove the truck 3,000 miles.
Do you run a fuel lubricant? if not you should be.
Have you checked the idle speed?
Does it stop smoking and run evenly when warmed up?
Usually a bad (leaking) injector causes a knock.
I have no idea if BD glow plugs are any good or not, there are allot of poor ones out there.

 

[luke2pl]

I am just trying g to figure if this could be from sitting so long or if it has happened after you drove the truck 3,000 miles.
Do you run a fuel lubricant? if not you should be.
Have you checked the idle speed?
Does it stop smoking and run evenly when warmed up?
Usually a bad (leaking) injector causes a knock.
I have no idea if BD glow plugs are any good or not, there are allot of poor ones out there.

when it warms up runs great. If I pull on throttle lock seems to smoke less. Once engine warms up some is gone. Today it smoked like crazy when I started it. When warmed up it was gone. Someone mentioned maybe TPS or Thermal advance switch.

 

[luke2pl]

when it warms up runs great. If I pull on throttle lock seems to smoke less. Once engine warms up some is gone. Today it smoked like crazy when I started it. When warmed up it was gone. Someone mentioned maybe TPS or Thermal advance switch. Previous owner did 2800 miles with no issues of any kind.

 

[Coug]

That really sounds like you have at least one glow plug not working properly.

 

[luke2pl]

That really sounds like you have at least one glow plug not working properly.

Today was raining and air was moist. It smoke like crazy. Got glow plugs last year from BD customs. Maybe they went bad.

 

[Coug]

Today was raining and air was moist. It smoke like crazy. Got glow plugs last year from BD customs. Maybe they went bad.

You need to check resistance on every plug, then also check to make sure every harness connector is showing 24V. It's not unknown for wires to look good on the outside but have high resistance or damage internally.

The fact that it goes away when you increase the throttle or after it warms up suggests it is a cylinder temperature related issue, which is what the glow plugs do.
I suppose there might also be a cylinder with poor compression when cold, or just lower than the others that could cause the fuel to remain partially unburned until warmed up.

My truck smokes badly when cold, because I still haven't gotten around to changing the glow plugs on the passenger side. Lots of smoke, then tapers off when warms up. Also decreases if I press the accelerator pedal.

Glow plugs are one of those hit or miss items. They should last for a decently long life, but all it takes is a couple times where you turn the start switch, turn it off, and back on again too quickly to start burning them up.

Just to be clear, you said this truck has 3k miles on it since rebuild, and the previous owner put 2800 of those miles on it?
Add to that, the start box and glow plugs were replaced 8 months ago, was that by you or the previous owner?
Has it smoked like this the entire time or did it just start recently?

 

[mgFray]

With my vehicle I ended up:

“new” glow plugs were counterits and failed, replaced them with good ones… found the start box was now bad. Replaced that. Then the cold advance sensor was bad… replaced that. And then found the head gasket had a coolant leak.

only reason I mention this. With your symptoms start with the obvious, glow plugs.. even if “new” verify. Then move to the start box/EESS.. then the cold advance temp sensor.. seems like that was the easiest order for me to diagnose this sort of problem, and I basically had all of the problems.

 

[luke2pl]

You need to check resistance on every plug, then also check to make sure every harness connector is showing 24V. It's not unknown for wires to look good on the outside but have high resistance or damage internally.

The fact that it goes away when you increase the throttle or after it warms up suggests it is a cylinder temperature related issue, which is what the glow plugs do.
I suppose there might also be a cylinder with poor compression when cold, or just lower than the others that could cause the fuel to remain partially unburned until warmed up.

My truck smokes badly when cold, because I still haven't gotten around to changing the glow plugs on the passenger side. Lots of smoke, then tapers off when warms up. Also decreases if I press the accelerator pedal.

Glow plugs are one of those hit or miss items. They should last for a decently long life, but all it takes is a couple times where you turn the start switch, turn it off, and back on again too quickly to start burning them up.

Just to be clear, you said this truck has 3k miles on it since rebuild, and the previous owner put 2800 of those miles on it?
Add to that, the start box and glow plugs were replaced 8 months ago, was that by you or the previous owner?
Has it smoked like this the entire time or did it just start recently?

Previous owner installed smart box from BD customs. He was the one that changed glow plugs. He did replace injectors as well but forgot to put a washer on one or couple. Not sure if that matters. Maybe will give glow plugs a crack. Someone told me could be injector pump.

 

[Coug]

Previous owner installed smart box from BD customs. He was the one that changed glow plugs. He did replace injectors as well but forgot to put a washer on one or couple. Not sure if that matters. Maybe will give glow plugs a crack. Someone told me could be injector pump.

All it takes is one failed glow plug to cause smoke. Several of the glow plugs are difficult to access, so not everyone bothers to replace them if the truck is still starting. I think for a while there I was starting my truck on only 2 or 3 good glow plugs in freezing conditions.

 

[luke2pl]

With my vehicle I ended up:

“new” glow plugs were counterits and failed, replaced them with good ones… found the start box was now bad. Replaced that. Then the cold advance sensor was bad… replaced that. And then found the head gasket had a coolant leak.

only reason I mention this. With your symptoms start with the obvious, glow plugs.. even if “new” verify. Then move to the start box/EESS.. then the cold advance temp sensor.. seems like that was the easiest order for me to diagnose this sort of problem, and I basically had all of the problems.

Worth a shot. Ordered cold advance. It can’t be the coolant leak because the Humvee mechanic I spoke with said if you do throttle lock and it stops smoking it’s TPS or cold advance.
Also there is no missing coolant and it does not bubble up or build pressure. No blow by in the engine as well. The other option could be injector pump as well.

 

[Coug]

Have you actually tested the glow plugs yet, or are you just going to throw money at it and hope you get lucky?

Until you put a multimeter on the glow plugs and check resistance on each of them, and verified that you are getting 24V to each glow plug connection, you are potentially just wasting money, as glow plugs are the usual failure point, and age of plugs means nothing, especially if you didn't do the replacement yourself to know exactly what was installed.

I haven't seen where you've actually done these checks, and if you have a multimeter they don't cost anything to perform or take very much time.

 

[Mogman]

Worth a shot. Ordered cold advance. It can’t be the coolant leak because the Humvee mechanic I spoke with said if you do throttle lock and it stops smoking it’s TPS or cold advance.
Also there is no missing coolant and it does not bubble up or build pressure. No blow by in the engine as well. The other option could be injector pump as well.

The TPS has absolutely nothing to do with the fuel system, I suspect your "mechanic" has less knowledge than you think, Coug (and others) have given some good advice, until you positively ensure the glow plug system and plugs are working correctly throwing money at it will not get it fixed.