Buying Advice Fuel System Cleaning Advice Needed

[TruChaos]

I have a Jinma 284. It has a little less than 20 hours on it. Since I've owned it, it runs rough sometimes, fairly smooth other times.

At about 12 hours, it developed a slight engine misfire and a slight noise with a little black and blue smoke on throttle up. I removed and cleaned the injectors and saw no improvement so I replaced them. It ran a little better with less smoke.

Then the smoke returned with a slight noise.
I removed the fuel line from the tank to the pump and cleaned the screen in the banjo fitting. It was full of debris. It ran smoothly for a few hours. Then today I started it and it's got a strong misfire and is knocking hard and blowing light blue smoke continuously.

I decided to remove all the lines in the fuel system and clean them. I removed the line from the pump to the filter and the nastiest diesel I've ever seen came pouring out. It was black with black particles in it. I've put 7 or so gallons of very clean diesel (crystal clear) through the tank and engine since I've owned it.

Here are my questions.

1) What's the best way to clean the system properly? I know how to flush the tank and lines, what about the pump? Should it be cleaned at this point?

2) Once I disassemble the injectors and clean them (being careful not to interchange parts between them) how can I keep them from leaking combustion gases? Last time I cleaned them, I could see bubbles of diesel and gases leaking from between the threads. I really tightened them well what's the solution?

3) I noticed that when I removed the breather tube going from the valve cover to the intake manifold, with the engine running, that air blows OUT of the intake manifold tube. Is this normal? I would think that there should be a strong vacuum. It surprises me that air would be blowing out.

Thank you,

 

[greg_g]

1. The source of the problem is sediment - rust & dead algae - the bottom two inches of your fuel tank. It's below the level of the tube that gravity feeds fuel to the sediment bowl. Park the tractor so the sediment bowl side is lower than the other side. Shut off the fuel petcock, disconnect the fuel line from the sediment bowl, then turn the sediment bowl AND the threaded connector tube from the tank. Hopefully they will come out as one piece, but you may have to remove them individually. It's messy, so be prepared with a bucket - to catch what comes out. While the tank was draining, I was up top with compressed air trying to move as much of the crud toward the drain hole as possible. Protect your eyes.

2. It's probably the copper seating washers. When you remove the injectors, it's imperative that you get the copper sealing washers out too. Otherwise the injectors may get reinstalled with either two washers - or none. Either way will cause such a leak.

3. Normal. It's venting crankcase fumes.

//greg//

 

[TruChaos]

Greg,

Thanks for the tank info I hadn't thought of that and I'll clean it today.

With the injectors, they weren't leaking at the point between the injector and the head, they were leaking from the point where the injector tip screws on to the injector. At the threads. I can't image tightening them any more than they are. Is some form of sealer used? Not only was I careful to get the copper washers out but I also cleaned the mating surfaces between the head and injector. I didn't have any leaks between the head and injector.

I can understand air venting from the crankcase on the valve cover tube however, the air is blowing out of the tube on the intake manifold.

Oddly enough, there is no air coming out of the valve cover tube but a lot of air coming out of the intake manifold. I can't visualize how this is even possible. Unless an intake valve is stuck open and blowing air back out during the compression stroke. But how would this account for a knock and light blue smoke?

While I have the fuel system apart today, I'm going to check the valve clearance.

Thanks again,

 

[greg_g]

All I can think of on the leaks, is that it just may take a bit more elbow grease (torque) to seal the threads. If that still doesn't work, I guess you can try pipe thread compound, I don't recommend teflon tape though. I had an aggravating hydraulic leak around a banjo fitting once. I was afraid to put too much torque on the bolt, for fear of crushing the fitting. Went on for weeks like that, till I worked up the courage to crank another turn or to into it. Ain't leaked since.

I don't remember any small hose fitting on either of my Jinma intake manifolds. Just the big 2 incher from the air filter housing. So I'm at a loss to explain what yours is for, or why it's BLOWING air. I had the clear 1/2" hose coming out of the fill cap/oil breather. But I've gotten rid of those Jinmas, and truthfully don't remember where the other end of the hose went. Hopefully somebody with engines closer to the age of yours may be able to help.

//greg//

 

[TruChaos]

The breather from the oil filler cap goes to a fitting on the intake manifold. The fitting on the manifold is where the air is coming from.

Today, I pulled it all apart. The valve clearances are good, the injection timing is correct. I cleaned the entire fuel system including the tank. You're right, no matter how much I tried, I spilled diesel all over the place.

However, I think I found the problem. When I was checking the injection timing, I noticed that fuel rises in only two of the three injection pump ports. The port closest to the rear of the pump is dead. The other two rise as expected. I bled the pump and rotated the engine at least 30 times and no action at all at that port.

I'm thinking at this point, that the injection pump is bad.

Thanks for the advice

 

[SPIKER]

truchos:

I belive that there is an adjustment on the side of the injector pump for each of the 3 pump strokes. this COULD be checked by pulling the inspection cover off. I don't know how to adjust them but I think I remmember reading about it someplace... there is actually very little inside one from what I remember someone else stating. some large dia bearings that is where the oil is at.

anyhow if you already found that there is 0 fule wellign up in the 3rd line after removing the line totally then I think you probably already found the problem and if you intend to replace the pump it shouldn't be a big deal to check it out.

here is genral fuel dia http://www.bright.net/~ispike/ipb/fuel/

mark M

 

[greg_g]

</font><font color="blue" class="small">( I noticed that fuel rises in only two of the three injection pump ports. The port closest to the rear of the pump is dead. The other two rise as expected. I bled the pump and rotated the engine at least 30 times and no action at all at that port.)</font>
The hand primer pump only pushes fuel as far as the end of the soft lines. It's of no use trying to force fuel up the hardlines. It's not quite clear if the no-fuel condition was detected at the bottom of the hardline, the top of the hardline, or the output of the injector. Please clarify.

//greg//

 

[Paddy]

Question for Greg.

With my KAMA 454 arriving soon, what would you advise I should do to get her ready? I know Chip will change fluids. But if the fuel tank is full of gunk from day one.... Seems Chip or I should just pull the tank befor she runs and clean it out.

What do you think? Any other items that should be done befor damage escalates?

Patrick

 

[bluechip]

Patrick,
We will check the tank, some have come with fairly clean tanks and others with cruddy fuel, perhaps it depends which tank at the factory is used to fill for testing. By the way, your tractor will arrive our place today after a delay for customs exam. The loaders are due in soon also so you should have your tractor before the end of this month!

Thanks
Chip

 

[greg_g]

</font><font color="blue" class="small">( With my KAMA 454 arriving soon, what would you advise I should do to get her ready? I know Chip will change fluids. But if the fuel tank is full of gunk from day one.... Seems Chip or I should just pull the tank befor she runs and clean it out.

What do you think? Any other items that should be done befor damage escalates?)</font>
Chip and I discussed the tank problem when I was over there in Nov. I think he's got a clean spare on the shelf that can be rotated into (dirty) new arrivals during assembly. Good chance that the dirty tank syndrome is a thing of the past, at least in those purchased from ARTRAC.

As far as the other stuff, I've been providing constant feedback to Chip on any remedial action or unexpected maintenance I've had to perform on the KM454. I'm reasonably confident that this should translate into a well prepared machine for you. Short of that, you are welcome to contact me via email with specific questions.

//greg//

 

[Paddy]

Thanks Chip/Greg.

Sound great. Once again, good dealers look out for you.

My Kubota has a fine screen at the tank fill location. Amazing all the crud you can prefilter.

Patrick

 

[greg_g]

</font><font color="blue" class="small">(
My Kubota has a fine screen at the tank fill location. )</font>
I used mine initially, just to see if it there actually was anything to filter out. Guess we have cleaner fuel around here than you, no crud. Since the mesh was so fine as to really slow down the fill process, I take mine out. Six gallon cans get really really heavy, while waiting for the fuel to seep through that fine mesh. Once the tank's full, I put the screen back in. For this purpose, the fine mesh works in my favor - as it prevents a sloshing full tank from dribblihg fuel from around the lousy filler cap seal.

//greg//

 

[TruChaos]

"The hand primer pump only pushes fuel as far as the end of the soft lines. It's of no use trying to force fuel up the hardlines. It's not quite clear if the no-fuel condition was detected at the bottom of the hardline, the top of the hardline, or the output of the injector. Please clarify."

I'm not sure how the primer pump got into the discussion but that's not what I was referring to.

When checking the injection timing, the crankshaft is rotated until the fuel begins to rise at the first port on the fuel pump. Then the pump timing is read from the crank pulley at the pointer. While doing this, I noticed that at the rear port, the fuel would never rise regardless of the crankshaft position.

My thoughts were that perhaps the rear port wasn't functioning.

Tonight, I removed the top cover from the injection pump and took a look at the plungers. I cleaned each one and reassembled the pump. Now all three ports splash diesel when the engine is rotated.

However, the engine still knocks and blows smoke.

 

[greg_g]

</font><font color="blue" class="small">( I'm not sure how the primer pump got into the discussion but that's not what I was referring to.)</font>

You said "I bled the pump". Since that's the express purpose of the hand primer, I assumed that's what you meant. The fuel delivery assembly is actually three separate components ; it's a combination fuel pump, governor, and injection pump all in one unit. It's fed by soft lines on the fuel pump side, and compresses fuel through hardlines on the injector pump side. So when you have fuel delivery issues, it pays to be specific.

So I'll ask again. Is fuel actually getting to the top of the 3rd hardline? And if so, is the injector actually triggering a fuel spray? Because the knocking and black smoke makes it sound like you're still running on two cylinders.

//greg//

 

[JohnS]

I think you have been chasing the crappy fuel through the system /forums/images/graemlins/crazy.gif

Most likely, an injector is bad or dirty. As you are running, crack open each of the injector lines, on top of the pump, one at a time. Retighten the nut before proceeding to the next. If you notice a change, knock smoothes out, that is the one to change. Hope this helps.

 

[TruChaos]

I don't think I stated that I started out by cracking all the hard lines to see if there was a change in the misfire or sound and there wasn't. I then replaced the injectors which didn't fix the problem.

When I stated that I "bled the fuel pump", I did exactly that, I loosed both bleeder screws on the top of the fuel pump and bled the air out of the pump then continued bleeding the system down the fuel lines to the injectors.

When I stated that fuel wasn't reaching the third port on the fuel pump, this occurred while I was rotating the engine to check the fuel injection timing. It had nothing to do with the fuel system purge or primer use.

I removed the entire fuel system except for the fuel pump. I cleaned everything and reassembled it.

I partially disassembled the fuel pump and removed the plungers. I inspected and cleaned them all including the piston function at the bottom of the pump, they work fine. While there was no visible dirt, or contaminates, I still sprayed everything with carb clearer.

The one thing I did notice was that the poppet under the problem port seemed to stick for some reason. This appeared to be due to how it was machined and not debris or contaminates. I would clean it then poke it with a clean plastic spray can straw and it wouldn't open. Then it would drop out and I'd put it back in and it work freely again. Then stick again. I inspected it for burrs and saw nothing, nor could I detect any from running my finger over it. The orifice it was seated in seemed very smooth. I hit the poppet with some 400 grit sandpaper, cleaned and replaced it.

I started the engine and it still knocked. I gave the third port a couple light whacks with a small hammer for good measure and still nothing (thought it might free the poppet). I was checking the fuel system for air bubbles bleeding everything while the engine ran then suddenly the engine knocked like **** and died.

From all the fuel system purging, I had run it out of diesel. I added some diesel, purged and restarted the engine. It started and ran without knocking. It did continue to smoke for a time then the smoke stopped. I ran if for an hour and the engine now runs better than it ever has.

What it was is anyone's guess but it sure wasn't dirty fuel. I bled and flushed two gallons of very clean diesel through the system.

Problem solved.

Thanks for all the help and suggestions.