Loss Of Power and Lots Of White/Grey Smoke On Mitsubishi 3 Cylinder Diesel

[JLinknc]

I have a 22hp Mitsubishi L3E Diesel engine that all of a sudden had a loss of power, knocking sound, and started blowing out lots of white/grey smoke that smells a lot like an old fuel oil furnace. I suspected a bad injector and loosened each injector fuel line one at a time. When I loosened the fuel line to injector 1, the motor started to die... When I loosened the fuel line to injector 2, the engine started to die... When I loosened the fuel line to injector 3, there was no change in the running of the motor. I assumed from that test, that the problem was connected somehow to that 3rd cylinder. I had an old identical parts engine with a busted block in the building and pulled one of the injectors out of it and swapped it with the one I assumed might be bad. Well, the knocking noise went away but the huge clouds of smoke and low power remained. So is this injector also bad but maybe not quite as bad as the other one since the knocking went away? I let it run for several minutes at idle and 1/4 throttle trying to get it up to temp to see if the smoke would clear. The smoke never cleared up and after about 10 minutes of running, it actually shut down as if I had flipped the switch. There is no water or fuel in the oil that I can tell of. It was getting late so I just left it and plan on picking back up tomorrow. I'm planning on swapping the problem #3 injector with either injector #1 or #2 that I know is working correctly to see if it is actually an Injector Problem or a problem with the actual cylinder. If the problem follows that #3 injector then problem is solved. Is there anything else fuel related that could cause those symptoms like the pump or injector timing that I haven't mentioned? I'm no mechanic and have no clue how to set the timing and I would think if the pump was bad then the problem would be seen across all three injectors instead of just that one...Of course I could be wrong about that. If the problem was low compression from worn rings then wouldn't the smoke have an oil burning smell?? If the head gasket was blown, wouldn't the smoke have a sweet smell and look more like a fog smoke? Anyway, any tips, advice, or help would be greatly appreciated. Thanks..

 

[medic0648]

Depending on the injector pump it could service each cylinder with it's own pump action and just have part of the pump bad. Could also be a bad line or clog. Also check the radiator for an oily film on top. May not be enough of a leak to show up in smell and it would sink in the oil sump.

 

[Tx Jim]

How long since fuel filter was changed and fuel flow from tank checked??????

 

[JLinknc]

Well... I switched out the 3rd cylinder injector with an injector from Cylinder #2 that I know is good, and I still have the same problem at cylinder 3. I was hoping the problem would move with the injector but that wasn't the case.. Any ideas? Only other thing I can think of is very low compression in that cylinder causing the fuel not to combust??? Any symptoms to look for that would point in that direction? So far this is what I have....No visible water in oil, no visible oil in water, no antifreeze smell from exhaust, lots of smoke that is a whitish grey in color and has a strong diesel fuel smell and is very dry if holding hand at exhaust. And a noticeable power loss.

 

[JLinknc]

Depending on the injector pump it could service each cylinder with it's own pump action and just have part of the pump bad. Could also be a bad line or clog. Also check the radiator for an oily film on top. May not be enough of a leak to show up in smell and it would sink in the oil sump.

I disconnected all three copper lines from the pump at the injectors all at one time and spun the motor over. I could not tell any difference between the amount of fuel coming out any of the 3 outlets. I guess it could possibly be a pump timing problem though.
I opened the radiator and there is NOT even a trace of any oily film at all.

 

[JLinknc]

How long since fuel filter was changed and fuel flow from tank checked??????

Fuel filter was changed out about 20 hours ago.. Its a see through filter and appears to be very clean. I can open the bleeder valve and fuel flows very freely. It has a 12v inline electric fuel pump and I've had one go bad before and the symptoms were a lot different. It just had a loss of power at top end but it ran smooth at idle. No abnormal smoke visible at all when pump went bad.

 

[bigdeano]

I would check the compression at this point. Could be a broken piston. I'm no expert on diesels, just guessing from the symptoms.

 

[medic0648]

Could be a ring, piston, or liner failure.

 

[JLinknc]

I just done a compression test.. thanks to Harbor Freight having Diesel Compression Testers in stock at my local Harbor Freight store. Not sure what the Compression should be but as expected, cylinder 3 has significantly lower compression than Cylinders 1 & 2. Here are the results..

Cylinder #1 --- 530 psi
Cylinder #2 --- 535 psi
Cylinder #3 --- 220 psi

I had heard somewhere that if you pour a little oil in the low cylinder and the PSI goes up on the second test then most likely it is a piston/ring/liner related problem. If the PSI does not raise after oil is poured in then it is most likely head related such as a valve/crack/gasket related problem. Not sure about this test though. Maybe someone with more experience here will know. Anyways, I did pour a little 10w30 motor oil in the top of the cylinder with the low compression and re-tested it and the PSI on the second test went up maybe 4 to 5 psi. For some reason I was expecting a much higher PSI difference with oil in the cylinder. Is that 4 to 5 psi raise enough to rule out a head related problem and assume it is piston/ring/liner related?

 

[Don87]

I just done a compression test.. thanks to Harbor Freight having Diesel Compression Testers in stock at my local Harbor Freight store. Not sure what the Compression should be but as expected, cylinder 3 has significantly lower compression than Cylinders 1 & 2. Here are the results..

Cylinder #1 --- 530 psi
Cylinder #2 --- 535 psi
Cylinder #3 --- 220 psi

I had heard somewhere that if you pour a little oil in the low cylinder and the PSI goes up on the second test then most likely it is a piston/ring/liner related problem. If the PSI does not raise after oil is poured in then it is most likely head related such as a valve/crack/gasket related problem. Not sure about this test though. Maybe someone with more experience here will know. Anyways, I did pour a little 10w30 motor oil in the top of the cylinder with the low compression and re-tested it and the PSI on the second test went up maybe 4 to 5 psi. For some reason I was expecting a much higher PSI difference with oil in the cylinder. Is that 4 to 5 psi raise enough to rule out a head related problem and assume it is piston/ring/liner related?

Gotta be real careful pouring oil into a diesel cylinder, you can end up with a snapped or bent rod in a heartbeat(hydrolock).

Just the compression test alone indicates that the engine needs torn apart, and when you do that, you need to have the head checked and more than likely redone. They will check for cracks, check the valves, and resurface the head.