Smoke on start up (not glow plugs)

[thompsoncustom]

My humvee has started to smoke on start up quite a lot for the first 3 seconds and then cleans up and is fine.

Things I've checked so far:

Glow plugs have 22.9v going to them when the Wait light is on.
All glow plugs Ohm good but 1 is bad (open) on the rear drivers side cylinder.
Vent line and filter are clear back to the tank.

So that 1 plug has been bad for a couple month and you could just see some smoke if you were looking but now there is a huge cloud and heavy smoke for 3 second. Smoke smells like fuel so I'm thinking maybe one of the injectors is leaking into the cylinder. I'm thinking of pulling all the glow plugs and using a bore scope to see which cylinder looks washed to identify the injector.

Any other tips on what I should check, after starting humvee runs and idles good.

 

[Milcommoguy]

IMO... Fix the one glow plug, then move on to the other checks if necessary. First time cold start with one plug out can produce a puff of smoke like you describe.

Simple stuff easy, then get all dirty. CAMO

 

[Barrman]

What color is the smoke?

Fluffy white is coolant.

Blue is oil.

Dirty white is cold cylinders not firing. Glow plugs.

Black is too much fuel.

 

[thompsoncustom]

IMO... Fix the one glow plug, then move on to the other checks if necessary. First time cold start with one plug out can produce a puff of smoke like you describe.

Simple stuff easy, then get all dirty. CAMO

Pretty positive it's not the glow plug just from the amount of smoke but your right might as well replace it to rule it out 100% I have 4 other diesels but no other experience with a humvee maybe they are super sensitive to dropping one plug? I'll try to get a video of it in the morning.

OEM plugs on the way

 

[Pstyckiewicz]

Where do you park it? How long does it sit between starting up. Could be moisture/condensation building up in exhaust. Or somthing burning off that gets in there?

 

[thompsoncustom]

Where do you park it? How long does it sit between starting up. Could be moisture/condensation building up in exhaust. Or somthing burning off that gets in there?

Just in the drive way, gets started and drove around town almost everyday. Went to take a video of the smoke this morning and it wasn't all that bad. Started it again this after noon and there was probably twice as much smoke as this morning.

I did some looking last night and it does seem the 6.5 really doesn't like losing even 1 glow plug so maybe that's all it is when the plugs get here i'll install them and give a update.

 

[Mogman]

You could be losing more glow plugs.
There is a theory that when any plug opens up the voltage/current to all of the other plugs rises causing a cascade effect of plug failures