Ok, long story short... 05 6.0 w/ 115,000, Auto


I had my truck in the shop for another head gasket repair. I had ARP's done at the dealer once under warranty, but they didn't hold for whatever reason.

This time:
New head gaskets, reuse ARP's.
Machine shop rebuilt the heads and machined and ringed them.
6.4 Banjo bolts
EGR delete
New water pump

I now experience a pretty good vibration starting around 3K and getting worse as it climbs. I already had the blue spring and fuel pressure under acceleration never drops too low, I think 67 at idle and 62/63 under throttle. It happens in neutral as well. It also does it when downshifting (decending hills loaded using engine braking) but goes away after rpm's get below 3K.

The shop put it on the scanner and said the ficm was looking good as far as they could tell. He said they couldnt really measure injector fuel flow above 2200 rpm or so for whatever reason. They want to replace the 6.4 banjo's with stockers then check, and eventually swap the ficm to see if that helps too.

Since it does it in neutral, we can rule out driveline. Also, since it does it during engine braking, I'm not sure its a fuel problem.

I'm thinking the balancer or flywheel. Would a bad valve or something in the head cause this?

What say ye? It is nice and smooth at idle (at least, for a 6.0 )

Thanks

 

DOWNPIPE ALIGNMENT

 

And tell them the 6.4 banjo bolts have absolutely NOTHING to do with your vibration. That's not even a good guess

 

Downpipe alignment? To clarify, its a shaking type of vibration not a noise type of vibration. I think that's what you mean right????

I dismissed their assumption of the banjo's as well. I don't really think its any kind of fuel problem. If it was fuel related, it should only happen under hard acceleration, not deceleration.

Since it does it in park, I should pull the serpentine belt and see if it still does it. That would rule out the accessories. I may try that when I get home (2 weeks)

Would a bad ballancer shake at low rpm too?

Thanks so far

 

Anybody else have any ideas?

 

i like mikes tinking myself, down pipe rubbing on cab or frame.
overfull crankcase
bad injector
bent rod
failing lifter
low compression
bad balancer

 

Ok, when I get home Ill make sure the dp isn't rubbing.

I know the oil isn't overfilled.

Could be a bent rod I suppose, I think 5 of the 8 cylinders weren't sealing. I sure hope not, I would hope the shop checked things while it was apart.

I could check the injectors by disconnecting them one at a time and revving it up and seeing that it gets worse???

I should be able to see any defects in the balancer visually correct?

Is there a way to check the lifters out? I don't think I have any bad pushrods (yet), the idle is smooth.

Thanks