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Diesel Mech question -Anyone smart???

alaska120

alaska120

Mayor McCheese
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Here's the situation.
1973 TD-25C. Turbo starts making some noise, like a knock or loud tap. Sound goes away. Engine starts running like crap (i.e., no power -but idles fine). Shut down the engine, pulled the turbo and sure enough, it needed a rebuild. Not seized, but the bearings were definitely pooped out and the fan blades were wedged in the housing.
Installed rebuilt turbo and...no difference. Still has no power. Like barely enough to move itself and thats it. Changed fuel filters, air filter and put fresh diesel in it.
Any thoughts???
 
nixon

nixon

Boned
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Just a WAG . But is it possible that The engine ate some of the turbo's blades ,or parts of the bearings when it let go ? If it did , I'm sure it didn't do much good for the valves ,pistons ,and injectors .
 
Melensdad

Melensdad

Jerk in a Hawaiian Shirt & SNOWCAT Moderator
Staff member
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Nixon may be onto something. Either a part of the turbo or whatever it was the caused the turbo to go out may bounced around the internals of the engine and dinged up a valve, pistol, injector, etc.

The injectors are critical, if those get messed up the engine is either getting too much or not enough diesel.

Also critical is the valve seal, if it doesn't seal because of a ding/dent on the edge then there is not enough compression in that cylinder and it will be running badly.
 
alaska120

alaska120

Mayor McCheese
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Well, I guess the next step is to pull the heads. As much as I don't want to do that job. Damn things are heavy!
There didn't seem to be anything missing from the turbo but I suspect something ended up dancing around the cylinder. Doesn't make sense that it would run the same way it did with the inop turbo but I'm running out of 'easy' ideas.
Guess its time to tear into it.
 
Adillo303

Adillo303

Diesel Truck Fan
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Can I suggest a laser thermometer to read the temp in the exhaust manifold by each cylinder? That might tell you if one is bad or it is across the whole motor.

If the whole motor, it is computer controlled? My Cummins is and if the computer gets cranked off it goes into "Limp Mode" runs like crap, enough to get you home. Takes a DRB tool to reset it.

Final suggestion, can you pull the injectors, examine them and do a compression test?

Hopefully dds will drop by.

I know more about Cummins than anything else. Hope some of this helps.

.
 
Cowboy

Cowboy

Wait for it.
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I damn sure aint smart , Worked on a few deisels before . But I,d drain the oil first & look at it for any metal , then pull the injectors next & see if theres anything suspicious there . Been awhile since I tore into a deisel . But if it aint poppin out of the airbreather or exhaust & no major rattling or bottom end noises & runs fine at idle . My bets on the injectors . Just my 2 bits . Best of luck . :smile:
 
Melensdad

Melensdad

Jerk in a Hawaiian Shirt & SNOWCAT Moderator
Staff member
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Cowboy said:
I damn sure aint smart , Worked on a few deisels before . But I,d drain the oil first & look at it for any metal , then pull the injectors next & see if theres anything suspicious there . Been awhile since I tore into a deisel . But if it aint poppin out of the airbreather or exhaust & no major rattling or bottom end noises & runs fine at idle . My bets on the injectors . Just my 2 bits . Best of luck . :smile:
Click to expand...

Before I would pull the heads I'd be looking at all the alternatives, including the laser thermometer (don't have one of those, I wouldn't have thought of it, but if you can borrow one its clearly worthy of a try). I'd also be looking at the injectors long before looking at the valves. And something as simple as dropping the oil out and looking for metal bits is a black mess of a job but might turn up a clue to two.
 
alaska120

alaska120

Mayor McCheese
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I like the temp check. We used to do that with snowmobiles when we raced back in the day (although we didn't have a thermometer - we just used our fingers!).
The engine has zero electronics so I can instantly rule the computer out. Had that problem with a Hitachi excavator though...
Might be able to pull the injectors but don't have a way to do a compression check.
 

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Snowtrac Nome

Snowtrac Nome

member formerly known as dds
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which fan was hitting the housing intake or exhaust if it was on the exhaust side i would guess no problem un less you have a muffler than that could be plugged if it was the inducer on the intake side i would be concerned of internal engine damage if the engine is misfiring you should feel it or hear it and you can prefornm a cylinder drop test by cracking your injector lines. if its just low horse power pm me your phone and i will walk you through troubble shooting
 
alaska120

alaska120

Mayor McCheese
SUPER Site Supporter
Yup. Thought about a black goo fishing trip. Might come up with something recognizable. Dropping that belly pan though...geez. Really gotta get a smaller rig!
 
Snowtrac Nome

Snowtrac Nome

member formerly known as dds
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alaska120 said:
I can crack the lines...what would I look for? Lots of leakage? Blowback?
Click to expand...
be careful the fuel is pressureized to about 1500 psi and it will blow right in to your skin. when yoou crack an injector you should here a misfire just like pulling a plug wire off your small block chevy
 
alaska120

alaska120

Mayor McCheese
SUPER Site Supporter
OK.
I remember doing that before on a 7.3L.
So...I'll get a thermometer gizmo and check temps. Then I'll try to zero in on the bad cylinder with the injector line. I guess when I get that done I'll check in. DDS, I think I have your cell# - ends in 83?
 
Snowtrac Nome

Snowtrac Nome

member formerly known as dds
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yes if all cylinders are hitting give me a call i will walk you through fuel system diagnosses
 
TOMLESCOEQUIP

TOMLESCOEQUIP

Just Plinkin Away the $$
Before you do anything......Pull the fuel filters.

Then get yourself a jug of powerservice diesel additive. A jug treats 250 gallons. Then fill the new fuel filters 50-50 with clean diesel & power service mix, (then bleed the appropiate parts of the system as necessary.) Then dump the rest of the whole jug in the tank. Fire it up & go work it hard. See if it doesn't come out of it.

More diesel problems are caused by bad contaminated fuel than anything else. This is the easiest & cheapest fix........& won't hurt a thing to try it first.

Powerservice is to diesel engines what seafoam additive is to gasoline engines.
 
waybomb

waybomb

Well-known member
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I'm going out on a limb here, but a kid working for me once did this. So it can happen again, I'm sure.

Rebuilt turbo on a Cummins. Installed it. Forgot to remove the plastic protector plugs. Kinda whistled for a while. Then it got real loud. Then the one on the exhaust side left the muffler in a loud bang and hit the ceiling. The intake one was whistling away.
 
muleman

muleman

Gone But Not Forgotten
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Sounds like the waste gate is stuck and not letting the turbo ramp up. You need to check for operation of the turbo to see if it is actually building any boost pressure.
Try Red power website or heavy equipment forums. Both have a lot of TD wrench heads.http://www.heavyequipmentforums.com/Forum/
 
fogtender

fogtender

Now a Published Author
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I would first take the turbo off and have it retested elsewhere, just because someone rebuilt it, don't mean it was done right.

Have had a lot of new/rebuilt parts that weren't any good after getting them back.

If the old blades were missing parts, then you have some major issues to deal with if they were injested into the engine. If they were all there, then I would suspect the Turbo rebuild and waste gate in it.

Just my thoughts on it.

If it is good, then start tearing into the engine... But Turbo's are easy to pull and put back on...

Can stop by and look at it if you want tomorrow...
 
Snowtrac Nome

Snowtrac Nome

member formerly known as dds
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a lot of wrenches are qiuck to blame the turbo there isn't much to go wrong with them and i'm betting its a non wasegated turbo. and you have a feul problem if the engine runs lean the turbo wont build boost pressure so one has to looook at egt vs boost pressure to figure out the preformance problems also you want to look at all rubber conections and ensure there are no air leaks most stock turbos are going to blow around 25 psi on high boost.
 
fogtender

fogtender

Now a Published Author
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dds said:
a lot of wrenches are qiuck to blame the turbo there isn't much to go wrong with them and i'm betting its a non wasegated turbo. and you have a feul problem if the engine runs lean the turbo wont build boost pressure so one has to looook at egt vs boost pressure to figure out the preformance problems also you want to look at all rubber conections and ensure there are no air leaks most stock turbos are going to blow around 25 psi on high boost.
Click to expand...


Have had two turbos that were rebuilt and were bad, just about pulled the entire engne apart before out of deperation had the turbo rechecked and one the waste gate was stuck and the other a bearing was installed wrong and caused the blade to hit the housing when it started to get warm and stopped the rotations of the blades.

If the engine was running right up until the turbo quit and it didn't injest blades, and replacng it with a rebuild didn't do the trick, I would recheck the turbo. Changng out injectors won't hurt a thing, but unless during the turbo replacement someone pulled the fuel lines off, there is no reason to assume they are now bad. Changing fuel filters is always good to do to ensure clean fuel, but again, the turbo and fuel system are two seperate systems that do two different things. Now if the unit had sat for five years since it was last run, then the fuel could have an Alge growth in it and would cause the fuel filters to clog up and starve the engine of fuel/power.

But again, I learned a long time ago if you replace a part that was bad that caused something to stop working, and a new replacement part don't fix it, go back and check the new part first to ensure it is good.

If in fact the engine was running fine and the coughs up the turbo, there is also a chance that some debree went past it to cause the blade damage and then went into the engine, but it wouldn't idle well then either if it took out a piston or stuck open a valve.
 
Snowtrac Nome

Snowtrac Nome

member formerly known as dds
GOLD Site Supporter
fogtender said:
Have had two turbos that were rebuilt and were bad, just about pulled the entire engne apart before out of deperation had the turbo rechecked and one the waste gate was stuck and the other a bearing was installed wrong and caused the blade to hit the housing when it started to get warm and stopped the rotations of the blades.

If the engine was running right up until the turbo quit and it didn't injest blades, and replacng it with a rebuild didn't do the trick, I would recheck the turbo. Changng out injectors won't hurt a thing, but unless during the turbo replacement someone pulled the fuel lines off, there is no reason to assume they are now bad. Changing fuel filters is always good to do to ensure clean fuel, but again, the turbo and fuel system are two seperate systems that do two different things. Now if the unit had sat for five years since it was last run, then the fuel could have an Alge growth in it and would cause the fuel filters to clog up and starve the engine of fuel/power.

But again, I learned a long time ago if you replace a part that was bad that caused something to stop working, and a new replacement part don't fix it, go back and check the new part first to ensure it is good.

If in fact the engine was running fine and the coughs up the turbo, there is also a chance that some debree went past it to cause the blade damage and then went into the engine, but it wouldn't idle well then either if it took out a piston or stuck open a valve.
Click to expand...
you are right on your statements and common sence should prevail the first thing i would do is put a pressure gauge in the boost tube or intake where there is a test port and ck boost pressure I'm guessing 15 to 25 psi thats a constant speed engine so i would guess there is no waste gate if you have no booost 1 ck all boost tube conections and intake cooonections soapy water can help #2 ck turbo is spinning #3 ck egt see if its high wich indicates low boost plenty of fuel a lower than normal egt will indicate a lean condition wich wil not spin the turbo properly this is all assuming the engine is mechanicaly sound yes rebuilds can also be bad like mabe the wrong inducer wheel and housing combo
 
Lyndon

Lyndon

Bronze Member
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I had a NEW 6.2 L diesel in '86. It started making the worst racket, sounded like it was going to throw a rod. I raced over to my diesel "in-the-know-guy". He says:"Relax Lyndon, it's just a stuck injector, put some Injector cleaner in it, it'll go away". that worked, got another 140,000 out of it before selling it. was still running fine.

I later found out that the fuel coming out of the timing injection pump was 2000 to 3000 PSI. A blocked injector leads to the hammering sound. I have since observed this unhappy phenomonom with some other diesels. A dose of injector cleaner worked. don't use too much and don't use it on a regular basis. It can lead to seals in the timing pump being eroded away and the engine will start smoking.
 
Snowtrac Nome

Snowtrac Nome

member formerly known as dds
GOLD Site Supporter
Lyndon said:
I had a NEW 6.2 L diesel in '86. It started making the worst racket, sounded like it was going to throw a rod. I raced over to my diesel "in-the-know-guy". He says:"Relax Lyndon, it's just a stuck injector, put some Injector cleaner in it, it'll go away". that worked, got another 140,000 out of it before selling it. was still running fine.

I later found out that the fuel coming out of the timing injection pump was 2000 to 3000 PSI. A blocked injector leads to the hammering sound. I have since observed this unhappy phenomonom with some other diesels. A dose of injector cleaner worked. don't use too much and don't use it on a regular basis. It can lead to seals in the timing pump being eroded away and the engine will start smoking.
Click to expand...
the fuel knock you are describing is actualy a semi hydro static lock condition as fuel dribbles instead of sprays out of the injector
 
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