Toyosha diesel question
 

I have a diesel related question and I'm hoping someone may be able to point me in the right direction. I'm working on my neighbors tractor, a Simplicity 9518 with a Japanese Toyosha 18hp 3cyl diesel engine.

The problem is when it starts it seems that the front cylinder isn't firing. There's a lot of white smoke out the exhaust. When it starts to warm up you can hear the front cylinder start to fire, or "come in". As it continues to warm up, it will continue to "come in" and "go out". After it warms up the front cylinder seems to fire ok and the white smoke clears up, but it will continue to miss at full throttle.

When you crack the injector lines open with it running, the back and middle cylinder make a big change in how it runs and the front cylinder make hardly any change on how it runs. This is why I believe it's a problem isolated to the front cylinder. I turned all the injector lines around 180° and hooked up the injectors out of the engine. When cracking, they all seem to have a consistent spray pattern.

Just spent $250 the other week and had the injectors rebuild. It does run better, but it wasn't the main problem. Compression in all 3 cylinders is 375-400psi. When checking the valve lash the other night, I noticed that you can push the valves open with your fingers. Does this seem right?? I checked the engine manual I have for my D600 and it said spring pressure should be around 14 lbs. This just seems very light to me. I'm now leaning towards a valve float or valve hanging problem. If I can find a head gasket for this Japanese engine I may just pull the head to have a look.

My neighbor keeps telling me it's the injection pump, but it doesn't seem right to me. You can turn the pump up until it's rolling black smoke under any load. That tells me the pump has the ability to supply enough fuel. I should also mention it doesn't lose any coolant or run hot.

White smoke....small coolant leak...head gasket? Bubbles in coolant?:bigthink:

Compression is 375-400. No coolant loss. Runs just fine with the cap off too. The white smoke is unburnt fuel, not antifreeze.

I would pull the prechamber and inspect it, I've seen glow plugs burn off inside and cause this same issue.

It still does this even after you rebuilt the injectors correct?


Spring pressure on these is very light. It's NOT floating a valve. Valve hanging up.... maybe. I'd say it's a valve issue, yes.


You really don't know anything about diesels do you? Just because the pump has the ability to make that little motor "smoke" doesn't mean that it's putting the same amount of fuel out to all the cylinders. It could be starving the front one. If it has the injection pump on it I'm thinking of, it could have a scored barrel on one cylinder. Or the delivery valve could be bad, or the lobe worn off the cam in the pump.....


My guess is it's a valve issue, or a blown head gasket. You just think it has good compression on all 3 cylinders. If it's a blown head gasket, it could be pushing compression back and forth between the 1 and 2 cylinder. Not as likely though as I believe the firing order on a 3 cyl is 1-3-2. Could be a valve hanging up, or not sealing. Could be a scored cylinder. Could be the injection pump. Best thing to do would be a cylinder leak down test. That would tell you if your chasing issues internally, or fuel related. No harder than it is to pull the head, you may opt for that too.


My biggest advice to you, is don't play mechanic for other people if you don't know what your doing.

You can pull the glow plug, but not the chamber, Ben.....

Ah yes, not sure why I was thinking they come out. Was thinking they were more like my Mercedes for some reason.

White smoke tells me that fuel is present but not being burned. On a diesel the fuel is lit by the heat of compression, so I'm with Jon on this one, valve issue or low compression due to head gasket / rings. Do the cylinder leak down test as suggested and tell us the results.

I can try to get a video of it running tonight.

White smoke tells me it's getting fuel and just not burning it. That is why I think this problem is not related to the injection pump. I was honestly expecting to see it down on compression.

I can do a leak down test on it and see what it looks like.

A video isn't going to help on this one.

White smoke makes you think it's getting fuel huh.... well, yeah. But if the delivery valve is bad, it may not be atomizing the fuel, or injecting it at the right time. White smoke does not mean the injection pump is in good working order. It just means it's trying to do its job.

You can dump gas down a carb and make an engine run. Doesn't mean you make a good carburetor.