After a 6-month hiatus, the smoke is back!

Edis06

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When I bought my HMMWV, it smoked on startup and during acceleration. I tried to sell myself on the idea that the smoke was white, but honestly it was blue. Like "OIL BLUE." After starting, I would have to back out of the garage quickly otherwise my eyes will nearly seize shut with pain. I had some techs look at it and they all said it's burning oil and there's nothing I can do about it except a rebuild.

Well one HMMWV-only mechanic in Florida told me just "drive it. Many problems like that just go away." Shortly after that the harmonic balancer failed and tore apart the keyway on the crank. If you saw on my previous posts, I repaired it and it worked! Not only did the repair hold up, the smoke magically disappeared! I can sit and ponder over why, but instead I'd rather not complain or ask questions. I'm thinking more along the lines of coincidence (correlation over causation) but whatever.

Here's the interesting part of the story. Last week the SMOKE APPEARED AGAIN! Same blue fog on startup and when revving. On the road at speed, there is a lack of power (same as before-I noticed when the smoke problem cleared up, the truck was significantly faster) and I can feel a "bump" of hesitation followed by a puff of smoke repeatedly while driving at highway speeds. Acceleration time is cut by about half.

HERE'S THE STRANGE THING - the next day after the smoke re-appeared, the balancer failed again. The keyway fix lasted 6 months and about 10K miles but it failed this time for good. Seems to me like there is a connection.

Anyway, rather than sourcing a new engine in a hurry, I had the balancer professionally welded to the shaft. It was a new balancer and pully anyway, so I'm sure it will outlast other parts of the motor. I repaired the keyway once again, replaced the key, and coated the entire area with "steel reinforced" epoxy before reinstalling. I did this because the heat created by the welder can cause metals to temporarily warp and the slightest rotation or wobble during the welding process will destroy the alignment of the v-belt pulley. The next day, we welded it. It's SMOOTH AS SILK NOW. The idling is perfect. However the smoke won't go away.

Any ideas? I mentioned the harmonic balancer story because of the odd coincidence the two occurrances happening at the same time. This is not my imagination btw. When it smokes, you cannot idle the truck in the garage for more than 10 seconds when before you could do it all day (although I don't recommend it!).

- there is no blow-by cold or hot
- when driving, it behaves like a bad fuel pump, failing when under load

I replaced the fuel filter and removed the fuel breather with no improvement. Is there a way to check the fuel pump? Should I replace it anyway?
 

frank8003

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After " professionally welded" harmonic balancer installation You pulled the valve covers and corrected any out of specification valves and valves settings and inspected all the fittings when She is running.
Didn't say if "harmonic balancer" was stock application.
 

Edis06

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After " professionally welded" harmonic balancer installation You pulled the valve covers and corrected any out of specification valves and valves settings and inspected all the fittings when She is running.
Didn't say if "harmonic balancer" was stock application.
No, should I have done that? I am NOT skilled enough for that and NOBODY in this area will work on a HMMWV, including the big diesel shops.
 

doghead

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Sounds like you have a misfire.

Welding the balancer just eliminated what it is there for. Next time your crankshaft will fail.
 

Edis06

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Sounds like you have a misfire.

Welding the balancer just eliminated what it is there for. Next time your crankshaft will fail.
Wait, how would welding it eliminate what it is there for? I fully understand the ability to replace it goes out the window, however this part is certainly not made to rotate. There is nearly a year wait for a proper engine swap and this is the most reliable bridge to getting the car on the road. I agree the crankshaft will fail if the balancer fails in the traditional fashion, but from what I've read and heard from the diesel techs down here, those keyways fail twice as often as the balancers. That's true for the Duramaxes too! 2014 Duramax, low miles, stripped keyway with a perfect HB. Unbelievable. GM really should come up with a more reliable system.

I agree it's a misfire, I'm just wondering where I should start looking, and why (or if) there is any correlation between the balancer failure and the smoke. Since it's feeling like a fuel delivery problem, I am replacing the fuel pump then cleaning the injectors. I'll be dropping the tank soon as well to replace the seal to address a small leak.
 

Mogman

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Harmonic balancers are nothing to screw with! When I was a teenager running a Kawasaki H2 down at the old San Antonio drag strip I saw a harmonic balancer take about the top 4" off of a guys head in the stands sitting next to his wife and kids....
Was off of a Chevy 327 IIRC
 

Edis06

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Harmonic balancers are nothing to screw with! When I was a teenager running a Kawasaki H2 down at the old San Antonio drag strip I saw a harmonic balancer take about the top 4" off of a guys head in the stands sitting next to his wife and kids....
Was off of a Chevy 327 IIRC
I don't doubt it!! Just carefully holding these things up above my face to align it is scary at times. If it falls, I'll be unrecognizable even to family.
 

frank8003

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Wait, how would welding it eliminate what it is there for? I fully understand the ability to replace it goes out the window, however this part is certainly not made to rotate. There is nearly a year wait for a proper engine swap and this is the most reliable bridge to getting the car on the road. I agree the crankshaft will fail if the balancer fails in the traditional fashion, but from what I've read and heard from the diesel techs down here, those keyways fail twice as often as the balancers. That's true for the Duramaxes too! 2014 Duramax, low miles, stripped keyway with a perfect HB. Unbelievable. GM really should come up with a more reliable system.

I agree it's a misfire, I'm just wondering where I should start looking, and why (or if) there is any correlation between the balancer failure and the smoke. Since it's feeling like a fuel delivery problem, I am replacing the fuel pump then cleaning the injectors. I'll be dropping the tank soon as well to replace the seal to address a small leak.
anti harmonics balancers do not drive on a key, although that helps, They are to be a press fit or all the entailed engineering of it will not function as per design.
 

doghead

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Originally, I thought you had welded the balancer together, not to the crankshaft. Sorry for the confusion there.


Start with your injectors. Intermittent misfiring can be cause by them.
 

Monkeyboyarmy

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Maybe crack the nut loose at each injector while its running to see which cylinder doesn't change, or changes the least, and to see if your blue smoke goes away temporarily.
 

Edis06

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anti harmonics balancers do not drive on a key, although that helps, They are to be a press fit or all the entailed engineering of it will not function as per design.
I totally agree. The problems occur when the bolt fails, loosens up and puts the strain on the keyway. Anyone who has ever held a 3/4" woodruff key knows those things are for alignment only.

There was a recall on the original bolt for an upgraded, harder steel one, which I replaced. Well, it still failed. Generally, I wouldn't recommend welding it on since you're sealing the fate of the engine to the lifespan of the balancer at that point, however I do recommend holding that shaft and torqueing the bolt to a few hundred ft/lbs with Loctite Red and paint marking it, making sure to check for movement on the paint marks during each oil change.

Mine was fairly damaged, and it wobbled very slightly until fully torqued indicating wear on the shaft, which is why I no longer trusted the bolt. This is why I torqued it first with the epoxy, so when the bolt had to be removed to fit in the weld, the epoxy would hold it in its intended position during the welding process.
 

Edis06

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Have you even bothered to check your injection pump timing? The smoke you speak of is retarded pump timing.
I haven't checked it yet. I suspected that at first but it's odd that the problem went away. Then I thought maybe the aggressive shaking retarded the timing slightly when the old balancer was mounted.

It idles smooth but misses when under load, and with each miss, a puff of smoke comes out. Looks to be blue but burns the eyes like unburnt fuel.

In checking the timing, should I just move the pump slightly to the drivers side of the timing marks?
 

Edis06

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OK, I took RetiredWarHorses' advice and played with the timing - FIXED!! It turned out the wobbling of the bad harmonic balancer certainly can play a role in the injector pump position. The pump was advanced slightly to the drivers side, so I brought it back to center. Then it ran worse, so I moved it slightly further to the driver side and now my acceleration and smoke is at a normal level. All my power is back. I am assuming the shaking of the engine slowly moved the position enough to affect the performance. Thanks to all for the advice!
 

toddperk

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i'm no expert but my guess is you have one/some cylinders/injectors that intermittently failing making your engine out of power balance. the balancer tries to correct but it is more than it can and breaks.

look for a miss fire or cylinder that is not contributing power
 

Edis06

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i'm no expert but my guess is you have one/some cylinders/injectors that intermittently failing making your engine out of power balance. the balancer tries to correct but it is more than it can and breaks.

look for a miss fire or cylinder that is not contributing power
It was corrected by adjusting the injection timing. 10 min job.
 
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