Smoke and Knock

[lds261]

Hello SS world,

I have pulled the trigger and purchased my first 1097A1. After finally getting it delivered I found that it had an engine knock and blowing white smoke out of the exhaust. Some coworkers and I agreed that the knock sounded to be an injector issue. I went ahead and just replaced all 8 injectors, however, the knock and smoke remain. Another symptom that is associated with this knock is that the volt meter bounces between the green and the red on the meter that corresponds with the knocking. Not seeing any coolant in the oil, however, I know that doesn’t mean I still couldn’t have a blown head gasket.

I’m at a loss as to what to check next. My gut is telling me there is an internal issue, but I’m looking for some suggestions and ideas of where to go next. Thanks for any and all advise.

lds261
1994 M1097A1

 

[Mogman]

Welcome to the forum!!

 

[NDT]

Is it missing AND knocking or only knocking? A thermal gun pointed at the exhaust manifold can help you determine if a cylinder is not contributing. Is the alternator firmly attached? They have a tendency to break bolts and then rattle.

 

[Mogman]

The bouncing of the volt meter may be the "after glow" that continues for 2-3 minuets after start up (the glow plugs are turning on and off to keep the temp up in the glow plugs but not burn them out), it does not seem apparent how the volt meter bouncing in time with the knock AND the smoke fits.
If the alt were bouncing around (knocking) and the volt meter was bouncing ok, but I cannot figure how the smoke comes into play..

 

[Mullaney]

Hello SS world,

I have pulled the trigger and purchased my first 1097A1. After finally getting it delivered I found that it had an engine knock and blowing white smoke out of the exhaust. Some coworkers and I agreed that the knock sounded to be an injector issue. I went ahead and just replaced all 8 injectors, however, the knock and smoke remain. Another symptom that is associated with this knock is that the volt meter bounces between the green and the red on the meter that corresponds with the knocking. Not seeing any coolant in the oil, however, I know that doesn’t mean I still couldn’t have a blown head gasket.

I’m at a loss as to what to check next. My gut is telling me there is an internal issue, but I’m looking for some suggestions and ideas of where to go next. Thanks for any and all advise.

lds261
1994 M1097A1

.
Welcome to the Outfit!

So, with a diesel smoke tells you a lot. White Smoke and Black Smoke mean something. White generally tells you that the temperature in the combustion chamber is too low. This can happen when either there is raw diesel fuel that passes through to the exhaust, engine coolant is entering the combustion chamber, or the piston or other components are worn, damaged, or possibly not correctly installed. A "rich" (strong) diesel fuel smell is part of this "white smoke problem" that need to be fixed.

• Faulty injectors – stuck open.
• Worn piston rings or cylinder glazing
• If equipped with glow plugs, could be faulty plugs or module.

If you have a really thick white smoke - and possibly sweet smell - you could have a water (coolant) problem too. Ideas below...

• Blown head gasket
• Cracked block or head
• Contaminated fuel
• Leaking Oil cooler (Through most of the time, the oil passes into the coolant)


To run correctly, a diesel engine needs precise timing of the injector pump and proper pressure. Any decrease in the pressure or delay in delivering the fuel to the combustion chamber will cause incomplete combustion, and you will have white smoke.

Then there is anpther lighter white smoke. This is a steady stream of of light smoke. It can even be random but often “puff.” Some likely causes include,

• A clogged fuel filter
• Low pressure in the fuel pump (Air in the fuel)
• Faulty or damaged injectors
• Incorrect injection timing (Worn timing gear or damaged crankshaft keyway).

Black smoke is often called "Rolling Coal" but generally - but not always - is a sign of too much fuel. Don't think that is your problem but we need more info to help you more.

 

[ToddJK]

With a cold engine, remove the radiator cap, start the engine. Make sure the coolant is full when doing this as you are looking for constant bubbles and it will intensify as it warms up. Typically if there's knocking and white smoke, I'd do a EPA and health nut no no and breathe some of the exhaust fumes for a moment to get a good smell, if it's sweet smelling, or anything like antifreeze, that's most likely head gasket failure. Bubbles constant in the coolant, that's sing of head gasket failure. Usually if it gets that far, coolant mixing with the oil is not far off as the gasket will continue to give way as pressures build.
I'm not very familiar with these diesel trucks engines, but things can also vary if the intake has coolant inlets/outlets, that possibly opens the door for intake gasket failure.
If no bubbles in coolant and the white exhaust smoke does not smell like coolant, then I'd check into other things as listed above. I'm no expert or mechanic, just a diy'er so take what I say with a grain of salt.

 

[lds261]

Good morning Everyone,

I apologize as I am not on top of message boards and how to post videos and add videos. I took a short video this morning of what I am talking about to give a little context to what I was trying to describe. The video isn't the greatest but you can see what I am talking about with the jumping of the volt meter and and knocking sound. The pulley squeal is new as that wasn't part of the original issue.

I know that it was mentioned about the glow plugs turning on and off causing a change in the meter, however, this video is after the cycling of the plugs.

Like I stated at first, it won't let me embed the youtube video so I just placed a link on here. Thanks again for all of your help.

HMMWV running

www.youtube.com

 

[Mogman]

It looks like the alt is loose, but that "tinny" knock sounds like a collapsed lifter.

 

[Mainsail]

Idle seems low to me.

Hard to see the voltmeter, but to me it looked more like the needle *snapped* vs bounced. Seems electrical (for that issue) to me.

 

[NDT]

Sounds awful. Rod knock is what I hear.

 

[Buck69]

I would open up the lube filter and check for debris before running it anymore. Agree with rod knock being a concern.

 

[87cr250r]

You have a misfire. These engines are normally very smooth at idle, you're is shaking. The frequency is wrong to be a rod knock, it's too slow. I think you'll find your problem is under a valve cover. You can crack injector lines to identify the suspect cylinder. In this case you should see no change in idle when you crack the line on the suspect cylinder.

 

[87cr250r]

Use this as a reference:

Bottom end noises (crankshaft speed) -

Top end noises (1/2 crankshaft speed) -

 

[Milcommoguy]

Play them both at the same time....

One heck of a problem, CAMO

 

[Buck69]

Rod noise can be a bit tricky in a diesel to identify. During compression, combustion and exhaust strokes, the piston is loaded down. It's when the piston gets to the top of the exhaust stroke that it unloads and will often contact the head. Not always the case but definitely can be. That would put it at 1/2 crankshaft speed.
Opening a filter to look for debris will quickly identify a bearing problem without possibly causing more damage.

 

[Mogman]

Does not sound like a rod to me, if it is the knock will change dramatically when given a little throttle.
If it were a rod and if that is a 6.2L it would not be worth rebuilding anyway..

 

[Retiredwarhorses]

It’s more often a bad injector…start by cracking an injector one at a time till the noise goes away…
could also have air in the system causing an injector knock…follow same above as it will purge air.

 

[dilvoy]

Good morning Everyone,

I apologize as I am not on top of message boards and how to post videos and add videos. I took a short video this morning of what I am talking about to give a little context to what I was trying to describe. The video isn't the greatest but you can see what I am talking about with the jumping of the volt meter and and knocking sound. The pulley squeal is new as that wasn't part of the original issue.

I know that it was mentioned about the glow plugs turning on and off causing a change in the meter, however, this video is after the cycling of the plugs.

Like I stated at first, it won't let me embed the youtube video so I just placed a link on here. Thanks again for all of your help.

HMMWV running

www.youtube.com

Sounds like a banging injector to me. Try some lucas fuel injector cleaner in it and let it idle for a couple of hours with having it raised in RPM a bit with the hand throttle. It fixed a truck I had that had that same sound. You could change the injector too, but why not try the easy way first.

 

[Mogman]

The OP stated he replaced all the injectors and it did not change the issue, running at high idle would be the recommended course of action for a stuck lifter.
Not to be confused with the common term in the diesel world where high idle is WOT without a load.
Some form of oil treatment would also be recommended.

 

[lds261]

First off, I would like to thank everyone for your comments and suggestions. Due to a busy schedule I don’t always have time to work on the truck and I can’t drive it until GP sends me the SF97.

Today I had some time during a power outage to work on it a little to further diagnose the problem. I agreed with everyone thinking it was an injector or lifter issue, however, I had wanted to change the oil in it before even getting it delivered. Upon draining the oil I had the luxury of finding metallic shavings on the drain plug which I was really hoping not to find. The recommendations of the knock being a rod is now looking to be the culprit.

I did throw some Lucas in with the oil change, however, I now have to start evaluating my options to either replace the motor, rebuild the motor, or attempt to sell it (which is what the wife wants lol) but I’m researching my options while I wait for the SF97.

Thanks again for all of the input.