Engine sound - don't like what I am hearing - Help me diagnose

[cattlerepairman]

Background, before today: Truck ran very well. Startup at first couple of turns, good power, some smoke when you lean into it (pump is turned up a bit). Unspectacular pre-trip. No oil in coolant or coolant in oil.

Today:
Cranked for a few seconds before it caught. I let it warm up and drove it. I did not like the sound. Boost gauge is fluctuating all over the place, loosely correlated with fuel pedal input, but "vibrating" all over the place (that is new). Truck smokes more (grey-ish) and seems down on power a bit. Runs a tad hotter than normal (185). When idling and "punching" the fuel pedal, there is a delay and it revs up with a "blub-blub-blub" sound, similar to a gas engine not firing on all cylinders. I tried to videotape, but it is really hard to appreciate.

The passenger side of the engine is much louder than the driver's side. The sound is best heard away from the truck.

Videos:
View attachment VID_20150510_153551.avi
View attachment VID_20150510_153758.avi
View attachment VID_20150510_153758.avi (stack; best one for the "pfft-pfft-pfft" sound type)


I was thinking

• blown head gasket (but I cannot see any exhaust gas puffing out)
• injector issue (stuck)
• valve issue (clearance or bent)

 

[m16ty]

First thing I'd check is fuel filters. Then I'd check the screen on the bottom of the in tank pump. The problem does sound fuel related.

 

[dmetalmiki]

I would check the injectors, pull and have them tested. (you can loosen each one in turn to check (if (which are not firing the engine)). after that, could be the h.h. or pump.

 

[RAYZER]

Pull the injectors and have them checked.
Do a compression test to see if it's a blown head gasket (compression leak).

 

[Jeepsinker]

I would say injector if it doesn't clear up with new fuel filters.

 

[M35A2-AZ]

Have you looked at adjusting the valves to see how lose they are?

 

[cattlerepairman]

Thanks for the input! I loosened the injector lines on idle, one by one, and there is no stumble or rpm change when loosening #1. I have a set of new nozzles on the shelf. Time to pull all six injectors, have the nozzles changed and the injectors pop tested and balanced.

Fuel filters are spin-ons and practically new. No water in the separator and fresh diesel in the tank. Valves are already on the to-do list! Makes sense to adjust valves when the injectors are out.

I found another post and it seems that my issue might be similar: http://www.steelsoldiers.com/showthread.php?44027-deuce-exhaust-sound-HELP!

 

[Jeepsinker]

Check the valves before you pull the injectors. Valve adjustment is free.

 

[gimpyrobb]

Nah, if he has new nozzles waiting, get it done! My truck would start and run and when I did my injectors, they were so far out of spec, I was amazed! Truck uses less fuel now too.

 

[cattlerepairman]

Pulled the injectors today and adjusted valve lash. Intakes were tight throughout. Definitely not good. Went with 0.15 intake (as per Jatonka) and 0.25 exhaust. #5 and #6 exhaust were rather loose. Definitely feel good that valve lash is adjusted.

Wanted to do compression test with my fancy original military compression tester and Multifuel injector adaptor, but the %#$#% gauge is wonky or leaking. Cheap China tool would probably have worked!!
Injectors go to the shop tomorrow for rebuild with new nozzles, pop testing and balancing.

 

[cattlerepairman]

Injectors back from shop, set to max pop pressure and balanced, ultrasound cleaned - look like new. They said the nozzles were fine and did not use any of the spare nozzles I provided, in case.

I still did not manage to do a proper compression test. I have a military injector adapter, used a copper seal and bolted it in place, just like the original injector, hook up the gauge and when I crank the engine I get a "random" compression number that does not stay. I also hear compression leaking. It is a seal issue and I could not get it right. I did not have all day to futz around, so I ended up putting the injectors back in and hooking everything back up.

She starts up and runs - more or less like before. On idle, there is a pronounced "chug" from the exhaust. From a distance, it sounds like an old Lister boat diesel or a farm tractor.

No leaks to speak of; the usual blow-by she has had since I got her. Coolant looks good, so does oil.

Test drive:

- power is down
- smoke is up
- EGT about 100-200 degrees higher
- runs hotter (normally sits at 165, regardless of what you do), now almost at 200
- difficult to revv match on downshifts; engine does not spool up fast enough
- idles at 750 and feels very rough doing that


Is it possible that something got sucked into the intake to cause this? Mouse or other critter? I'm trying to think of the simple things first.
Could still be fuel issue...can the HH fail to provide sufficient pressure to one particular injector line?
I guess nasty things such as a cracked or perforated piston could cause these symptoms, too. The engine clearly has blow-by.

 

[Jeepsinker]

Well all that leaves is a valve issue or a piston with a hole in it. You have adjusted the valves right?
Ok, I see that you did. Looks like you'll be pulling the heads to see if it is a piston or a bad valve. That sucks man.

 

[Jeepsinker]

Have you looked at your turbo recently? I wonder if some fins might have made their way into a cylinder?

 

[cattlerepairman]

Have you looked at your turbo recently? I wonder if some fins might have made their way into a cylinder?

Affirmative on the valve adjustment. Also, valve train looked ok; no sludge or unexplainable metal shrapnel.
Negative on the turbo, have never pulled my D-turbo since I have the truck. Interesting though....on my test drive I was thinking "It makes such a racket, I can't even hear the turbo spool". Hm. I have a muffler, so the turbo is quite subdued. However, I don't remember hearing it at all.

I will be away for work for the week, so no action before the weekend

Hole in a piston would be a costly exercise....new piston, new liner, new headgasket...

 

[gimpyrobb]

If the turbo is off, you should be able to inspect it easily.

 

[Jeepsinker]

Well you can do the standard cursory check of the turbo by just removing the intake tube and looking at the turbine wheel and checking for bearing play. If it lost fins he should be able to tell just from that.

 

[Truckoholic]

Given the symptoms in the original post, the very first thing I said to myself was "His turbo is bad". I'm surprised it took so far down the list, and so much other work before the turbo was finally brought up. All of the symptoms he mentioned, are exactly indicative of a bad turbo. Too bad I didn't see this post earlier.

 

[gimpyrobb]

I haven't really seen many turbos on these trucks go bad.

I did run a truck out of oil and that F-ed up the turbo pretty bad, but it wasn't really the turbos fault!

 

[cattlerepairman]

Pulled hose coupler off the turbo. All vanes there, no in-out play, a tad lateral play (just feel-able) which I deem normal without oil pressure. Spins freely and smoothly. Unlikely to be a turbo issue. These are my fingerprints on the vanes!

That means, heads need to come off and then a decision on repair/refresh or engine replacement.....depending upon what I find......not looking forward to that, at all. I guess there is a first for everything.

 

[gimpyrobb]

Well, I am sorry to hear it, as this means you have to dig into the motor.