Rich with your vibration being at said rpm and that you have changed the tc and flex plate I would say I would start thinking about the harmonic balancer. I remember when Roland had installed a Fluidampr he had seen an improvement and I recall reading somewhere else that there was a guy with a engine vibration and a Fluidampr cured it. Just trying to help you spent money $$
Fluidampr 720211 7.3L Powerstroke 1999 to 2003

 

Good call Ed, I never thought of that. Now the question is what makes the OEM harmonic balancer go bad? I mean all it is a piece of steel.

 

Can't remember where it was but I read the stock dampeners are steel and rubber. the rubber dries out and falls apart and doesn't balance properly anymore.

 

Never seen someone with so many issues... work so hard to fix them... and still not have a truck run right?

Wow...

 

Diane really.....reported post...

 

Well that makes sense if it has rubber on it.

 

Rob that is a good question. In the past I have had issues with engine vibrations that found their way all the way to the prop on a boat and had a hard time finding what the issue was. I seen first hand that Fluidampr can really cancel out harmonic vibration. But to answer your question. I think Fluidampr gives a clear cut answer to this question. This is per their website.

"What causes the inertia ring on a stock damper to move on a high-performance street application?
In a stock damper, inertia ring slippage is usually due to deterioration of the rubber strip. As the stock damper ages, the rubber strip begins to crack and lose its grip—in essence, it becomes "overworked." Also, rubber is a poor dissipator of heat. The more severe the crankshaft vibration, the more heat builds up. This causes the damping characteristics to change, which may well lead to damper failure over time."

I have a feeling Rich's latest problem at 1800 rpm is a harmonic vibration problem and rears it head in the CCT. Just something to think about.

 

I just had a persistent vibration issue cease with the purchase of new tires. I would have never guessed!

 

Thanks Ed for that school lesson. I never knew they had rubber in them. Learn something new everyday on her.

 

The Fluidampr makes sense. I saw this quote from the link above "A new Fluidampr 720211 7.3L Powerstroke Fluidampr Replacement Harmonic Fluid Dampers on your diesel truck will protect your engine from destructive torsional vibrations."


Let's roll with the Fluidampr for a minute here. According to the quote I found... it's entirely possible I had an issue where this would have helped, but before things progressed to a growing shake with valve noise.
If this is the case... how am I to know what's imbalance from a failed dampener, and what is engine damage from said failure?


I've been fighting this vibration for months and many thousands of miles - maybe I missed my window... maybe not. What's the troubleshooting technique... fire off a round and see how it goes?


Will the viscous fluid inside make Stinky start with a shake, then settle to a silky "standby" mode?

 

"Will the viscous fluid inside" The only way it would cure the problem is if the only problem was a bad harmonic damper. But it could be a combination of little issues coming together to create a harmonic vibration. Just guessing on that?? But I do know that harmonic damper that isn't doing it's job correctly will throw valve timing off to some degree. If it wasn't for a harmonic damper on piston driven engine a crankshaft would twist the shaft into pieces. I've seen it happen on big bore, stroked BBC marine engine.

Here is a better link because I know I can't explain it.
Fluidampr Performance Diesel Dampers for Ford Powerstroke

 

Can you duplicate the vibration in neutral at a stop at say 1,200-1,800 RPM?

 

Yes, but it's much milder without the load. I know from experience that shake/vibration can be a tune issue or an injector issue. I drove 2000 miles on vacation last winter without any vibration, shake, shimmy, or anything like this - and the tune wasn't changed before this problem showed up. The second the idle validation switch opens up, all PERDEL readings go to zero - so I will never find the offending cylinder this way.


I could feasibly have an injector imbalance with no real way to test that above idle, but this one fact eliminates fueling altogether: The problem is just as bad downhill in gear with FIPW of 0.6 ms. For those inclined, hook up AE, Torque, Scan Gauge, Infinity, or whatever (key on, but not running) and look at the FIPW: It says 0.6 ms, this is the sync signal from the PCM to the IDM, but the injectors are off. Since the shake is there with the injectors completely off, I must rule out tuning and fueling.

 

Rich I think that with the data you have collected you have done a great job ruling things out as far as the root of the problem. Now as far as you saying
"I could feasibly have an injector imbalance with no real way to test that above idle."
It makes me wonder in this case would you be able to send the injectors to a injector rebuilder have them put on a flow bench and have them tested? I don't have a clue what they can actually do or test for with a flow bench, I just wondering?? But from everything you have said and from the data you have logged I think it would be safe to say that it is not a tuning or fuel issue. I know I am throwing ideas out there that are from left field and are unlikely but I am just thinking outside the box as far what does what. Now you had said in the past you also had some valve, lifter or valvetrain noise. Have you checked push rods for straightness and length? Because when you say "all PERDEL readings go to zero" that leads me away from a bad harmonic damper but yet not counting it out. Because I would think if a harmonic damper were bad that it could or would affect the PERDEL to some effect. So that blows that theory out of the water.

Where like TransBrain asked about vibration in neutral at said rpm. For me working on gasser marine engines one of the ways to see if you might have a harmonic damper issue is to check the timing with a timing light at idle, 1500rpm and at 3500rpm with and without load. And if the timing deviates much more then a couple of degrees or timing marks are all over the place it can be a bad harmonic damper. But with these diesels I don't really have clue as to how to rule it out as a root of the problem.

 

And you said the converter and flexplate have both been replaced and the symptom stayed the same?

The converter doesn't happen to be a silver or gray color by chance?