Miss on startup, Miss under load, white smoke, stuck injector? They test fine. Odd.

[volver]

Short story: multifuel starts with a miss, smokes white, a slight miss can be heard under load, low on power, runs hotter than normal. You would think a stuck injector but all Injectors pop test fine. Odd. Any ideas?

Long story: The Hydraulic Head cracked 100 miles from home. I leaked 50 gallons of fuel on the highway at 40 miles an hour all the way home. Truck ran out of fuel 2 block from my house. 3 of the injector lines were leaking at the HH.

I replaced the HH with one from a used pump. Why was this pump taken out of service?

Engine starts and runs. Truck can now do work. Something is different and wrong.

If the engine is shut down for an hour or more it starts with a miss. Fires right off within​ one revolution, but misses for a second or 2. Then the miss goes away. At idle the engine smokes white even at operating temperature.

When accelerating the exhaust tone has a miss. Engine doesn't shake. Just sounds different. Also engine is down on power. Engine temp comes up faster than normal and is running 15 degrees warmer.

No mixing of fluids in the engine, I refueled with straight diesel, I changed the filters, electric fuel pump works, I sprayed seafoamed directly into a freely spinning turbo, I reset the valve lash, I pulled the injectors and brushed carbon from the tips and ports in the heads, I pop tested the injectors all are opening at 3500psi good pattern no leaks, I compression tested with engine warm and found each cylinder at 525psi. I checked timing the crank and pump line up the indexed tooth on the HH is one tooth past the mark as it should be.

I reinstalled the injectors and strated the engine and ran till warm. I shut the engine down. I restarted the engine 2 hours later. the miss at start still occurs, the smoke is less but still present, haven't tested under load yet.

I'm thinking the used hydraulic head has something wrong with it. What do you diesel experts think I should try next. Really the HH is the only thing in the equation that has changed. Unless limping it home broke something. I'm getting frustrated.

Thanks,
Matt

 

[volver]

Had a chance to work on the engine again. I started the engine then monitored the temperature of the exhaust manifold ports with an IR gun. All the ports were within 10 degrees of each other.

I cracked the line nuts in hopes the smoke would stop when I got to the bad injector. Smoked on all. #1-5 caused a more noticeable stumbled than #6. Cracking open #6 doesn't​ change the exhaust note much also doesn't add to the shaking.

Poked around with a mechanics stethoscope. All the injectors and cylinders sound about the same. I found something​ odd on the injection lines. There is a loud knocking on each time fuel is sent to the injector. #6 does not make the knock noise untill the nut is cracked.

I wonder if #6 is my problem.

I'm going to pull #5 and #6 again. Retest on the pop tester. Then switch which cylinder they go in.

 

[gimpyrobb]

Not sure how I missed your thread when you first posted, but it sounds like your on the right track. Let us know what you find out.

 

[someoldmoose]

Stay after it. Only two reasons a diesel cylinder won't fire. Wrong compression ( bad rings, tight valves ) or wrong fuel ( amount, quality, or timing). Do you get liquid from all the lines when you "crack" them at the injectors ? Sorry if you already answered that.

The "white" smoke is what concerns me. I presume these are wet liner engines ( if not, then I learn something today ). If the smoke is consistent while running, with and without miss, I would suspect that an amount of coolant is being drawn in during intake stroke. Watch your coolant level for dropping with no external leaks. If a tiny amount should get into a cylinder while parked and shut down it could cause a miss for a few seconds at start-up. I hope this isn't the case, but you asked. Just an air bubble in the HH or injector lines would be my hope.

 

[rustystud]

Check the fuel line itself to #6 . There could be a crack in the line (tube) or fittings. Check the "ferrules" on the end (tube) of the line. Can they be moved ? Or are they tight to the line ? Also check where it screws into the Hydraulic Head.

 

[someoldmoose]

Right on rustystud, as usual from all I've read. I only bring up the liner issue because they are sinister unless severe enough to be incredibly obvious. Chased one for over a week in the shop. Finally found it by making a fitting and doing an old fashioned leak-down test. Tiny bubbles, in the coolant. Not a fun song.

 

[winfred]

does the smoke smell like kerosene? that would be a fuel issue, usually not enough temp to burn the charge via pressure or timing

 

[volver]

Smells like diesel fuel. Don't seem to be loosing coolant. Compression check is great. I may have to do a leak down test. All fluids are normal. No mixing. No leaks on the injection lines. Maybe they only leak air in but not fuel out. Work on it again Monday or Tuesday.

 

[volver]

I swapped #5 and #6 injectors positions. After starting the engine I saw less smoke from the exhaust and it seemed to puff intermittently. There was always a knocking combustion sound since I got the truck. That sound is gone. Engine sounds smoother. After letting it run at 1100 rpm for a while the smoking returned to normal. It is definitely Diesel smoke. The sound of the fuel lines to the injectors did not change when using the stethoscope.

Maybe #5 or #6 in making a poor injection intermittently. The fault is not showing up with my pop tester. Once the new cylinder was coated in unburnt fuel the smoking returned to normal.

 

[volver]

Where can I get new Injectors for an LDS-465-1a?
2 hole injectors.

 

[frank8003]

What?
"I swapped #5 and #6 injectors positions."


Do not use 100% tankful of "todays" diesel fuel. It is not for that engine.
Dump 5 gallons, [or one or a quart or something!] of new motor oil in a whole tank of that crap diesel.
Don't fix stuff what aint broke.
You don't tell of hours and passing time on the engine as you
research perceived faults
It souds like an fuel problem"
How long you run that puppy?

 

[volver]

Moved injector 5 to cylinder 6 and injector 6 to cylinder 5. The fuel is mostly diesel. It is still black because of some used motor oil still in the tank. Engine has always run with no smoke even when running mostly used oil.

 

[volver]

Pulled the injectors again. This time I took the nozzles apart. Cleaned and back flushed everything. They all look good. Pop test fine.

Engine smoking just as before. I'm going to buy a new hydraulic head tomorrow.

 

[frank8003]

Pulled the injectors again. This time I took the nozzles apart. Cleaned and back flushed everything. They all look good. Pop test fine.
Engine smoking just as before. I'm going to buy a new hydraulic head tomorrow.

cool beans

 

[volver]

I needed to use the truck to pick up lumber. I noticed that the miss under load was gone. After running it hard for a couple hours the smoke stopped.

So I think there was an intermittent problem with one of the injectors. Cleaning them fixed the problem.

I just finished installing a boost gauge and EGT gauge. I turned the fuel up to 1000 degrees under load. Engine has never ran better.

Thanks.

 

[gimpyrobb]

1200 is even better!