tractor firing on only 2 cylinders

[johnanda]

Hi,
This is my first post, so here goes. Our neighbour who is retiring gave us a grey Kubota L2202DT 3 cylinder tractor. The tractor had overheated as the radiator core collapsed, and the following repairs were done. New radiator core, thermostat, water pump, temperature sensor, and a new head gasket, which fixed the overheating. I had the injectors serviced, checked the flow of fuel(all filters etc., were replaced) pump seems to give same flow to each injector, but no matter what I try the fuel does not burn and black smoke and lack of power continues on the same cylinder. It is always the same cylinder.
I am a retired fitter/turner/toolmaker by trade, so am sure I've done all I can do. What do you recommend as my next step? Should I call in an expert? I live in Australia, by the way!
Thank you for any advice.
John

 

[MagKarl]

Have you checked compression?

Have you observed the spray from the injectors?

How do you know it is the same cylinder? I would switch the injectors and see if the problem follows the injector or the hole.

If a cylinder isn't firing, typically smoke is white/blue and very strong smelling. Black is usually excess fuel, more than can be burned.

 

[North Idaho Wolfman]

I agree black smoke is over fuel, either you have a bad injector (but you said you had them serviced so you could rule that out) the injection pump is turned up or not operating properly.

First, do a compression test to eliminate that.

Next Run the tractor briefly, min or less, shut it off, pull the injectors and look for a wet cylinder, if they all look wet and the same then it could be a timing issue or fuel is turned up too high, if one is wet, swap then injectors to a dry cylinder, run again if the wet follows the injector then its a bad injector if it stays in the same place it's a bad injection pump.

You could also connect the injectors, out of the motor, to the injection pump and use a piece of cardboard to see the spray pattern, look for a heavy pattern, if they are all heavy then they are turned up, or timing is off if one is heavy then swap injectors around, if it follows the injector it's bad, if it stays in the same place injection pump needs rebuilt.

 

[johnanda]

Thanks all for the input. Should have been more specific. Have swapped injectors and the one cylinder only is always wet. Have checked in case of oil leakage by removing and watching the spray, which looks fine against cardboard, but I didn't check all three sprays. Without the injector the cylinder stays dry. I assume by compression test you mean the cylinder compression? Is the consensus that I should look at getting the fuel pump serviced as I only checked the spray at the problem cylinder?
Not being a diesel mechanic, I have to learn on the job.
Again thanks, any advice is welcome.
John.

 

[North Idaho Wolfman]

Check all of the injectors on all of the injection ports that's the only way to get a good comparison.
if one is heavy flow swap the injectors on the ports and see if it follows the injector or the port on the injection pump, I'll bet it follows the injector.

And it's not a fuel pump it called an injection pump.
On your diesel it has a lift pump (low pressure, low flow pump) and that feeds the Injection pump (that sets the amount and timing of fuel delivery) then you have the injectors they limit the fuel and set the spray pattern.

 

[johnanda]

Thanks for that.
Have done as requested, unfortunately I'm not sure if I spotted any difference in the spray pattern, but no matter which injector is switched, it always ends up with unburnt fuel in the same cylinder. So unless you can point some other way, I'll check the compression in the suspect cylinder, and if that's OK I'll send the "injection" pump to the experts for checking and repair if required.
Again thanks,
John.

 

[ipz2222]

If the injection pump is bad, it wouldn't be running and the same cylinder would not be the same problem. You need to check the compression. I don't remember what the compression is but it is much higher than gas eng. I think you'll need at least a 500 lb guage.

 

[North Idaho Wolfman]

If the injection pump is bad, it wouldn't be running and the same cylinder would not be the same problem. You need to check the compression. I don't remember what the compression is but it is much higher than gas eng. I think you'll need at least a 500 lb guage.

Sorry I have to disagree, it can run with a bad injection pump if only one of the pumps is bad.
But it's highly unlikely that it would over fuel a cylinder (wet cylinder), it would normally starve it for fuel, I'm going with lack of compression or bad valve / valve settings.
Do a compression test and if that looks good you need to pull the valve cover and check the valve train.

 

[johnanda]

Thanks again,
As per your advice to check compression, I am in the process of purchasing a suitable compression tester, and when I have results on all 3 cylinders I will let you know.
Again thanks

 

[johnanda]

Hi, yet again, and thanks for all the advice, to someone who had the skills, but not the knowledge.
I now have the tractor firing on all 3 cylinders. I dismissed the injection pump on your advice, the compression was within limits on the suspect cylinder, so I checked the valve clearances, again using information gleaned from the internet, and re-set the valve clearances on the problem cylinder.
This fixed the smoke and lack of power immediately.
When I replaced the head gasket, with hindsight, I should have checked the valve clearances, and again with hindsight, I would recommend everyone does this after replacing a head gasket.
I also own a 2nd hand Ferguson 35 diesel tractor, which we've used for over 30 years, so if I have any problems, I'll know where to come.
Again thanks,
John.

 

[North Idaho Wolfman]

Great to here you got it up and running!

 

[ipz2222]

Was the valve clearance too loose or too tight???