Injector pump / engine timing

[firefighterfox]

Hello forum. I have recently purchased a Yanmar 4300 non-running tractor with loader. Compression was low. I pulled the head and replaced all valves, 3 new exhaust seats, lightly honed cylinders and replaced rings. Ring gap was still within factory specs. Compression was around 200 psi before and now is around 420. Probably will go a little higher once the rings seat? The problem is the engine still will not run. The engine is basically the same as a John Deere 950 and uses a 3 cylinder in line injection pump bolted to the side of the block. I have bled the fuel line, injector pump, injector lines and have fuel all the way up to the injectors. I also installed new injector nozzles on the rebuild. I have read the timing procedure and it refers to a "timing fixture tube"? I would like to check the injector pump timing. I don't know if the previous owner tinkered with it or not. Any ideas or suggestions on how or what to do next? I think I'm pretty close to getting this beast running, I hope. I know that what I have done so far had to be done so there has been no wasted time or money spent. I am thinking timing, injector pump or somewhere in that area?
Thanks again for any help.
firefighterfox

 

[doxford jim]

Do you get any fuel through the injection pump at all?
Have you gone through the fuel system and checked things like fuel lines clear of debris, air intrusion, lift pump working, new fuel filters etc. ?
If all these have been done then it could be fuel pump timing problems. You need to determine TDC for #1 cylinder for this procedure. It could be that the fuel pump is out of timing by a little or a lot. Given these engines are four stroke, the cylinders fire only once in two revolutions. It could be that the injection pump was installed on the wrong TDC -. You need to determine that the engine valves are closed when the engine is at TDC for the injector pump to deliver fuel at the correct time.
When the cylinder TDC has been determined and the valve requirements confirmed, you can then use the spill method to determine when the injection pump is delivering fuel. Disconnect the line to the #1 injector and adjust the fuel pump so that fuel just starts to come out of the injector line connection. That is when the injection pump is starting to deliver fuel. Lock the injection pump adjustment at that position, replace injection fuel line, bleed all injectors and then retry. If you have done this correctly and all injectors have fuel, try starting the engine - it should run.
To get a better idea of what is done, try googling "spill timing for diesel engines" or similar wording. You could also connect clear plastic tubing to the injection pump outlet and this might make for better observation of fuel movement.
Don't forget that fuel pump timing is determined with the fuel being admitted BTDC - probably 10 degrees would be a good guess to start with.
Hope this makes sense for you - you might need to do a bit more reading or research.
HTH and good luck with the restoration.
Cheers

 

[doxford jim]

Ooooops - I forgot to mention the injection pump fuel shut off.
Usually with an inline fuel injection pump, the fuel delivery is regulated by the fuel rack which turns the barrels inside the fuel pump, to admit more or less fuel as needed. If the rack is stuck in the shutoff or no fuel position, then the injection pump will not pump fuel.
You will need to determine that the fuel rack is free and can be adjusted properly. Also, there will be a governor at the end of the fuel pump shaft that regulates delivery. This should be free to move to do it's job. Sometimes parts can rust and cause problems. There should be some lubrication inside - often it shares the inline fuel pump oil sump. Injection pumps vary so it would be a good idea to check if the injection pump does have an oil sump. If so drain it and refill with new oil - these sumps can get filled with diesel fuel from leakage from the barrel and plunger arrangement. Diesel can cause rusting if there is sufficient moisture content - causes injectors to seize etc.
So, check up on the tractors fuel injection pump etc. Last but not least, there ios usually a fuel shut off on the tractor to stop the engine manually - does it work properly. Could be either a pull cable or and electric solenoid. Just maybe the shut is stuck in the stop position.
HTH

 

[doxford jim]

Last but not least, how old is the tractor? Does it have any safety arrangements like clutch switch, seat switch etc. that could be sending an electrical signal to shut off the fuel to the injection pump - for whatever reason. This could cause your problem if all the safety checks are not satisfied - something as simple as a broken wire, bad switch etc.
Lots of stuff for you to think about.

 

[firefighterfox]

Last but not least, how old is the tractor? Does it have any safety arrangements like clutch switch, seat switch etc. that could be sending an electrical signal to shut off the fuel to the injection pump - for whatever reason. This could cause your problem if all the safety checks are not satisfied - something as simple as a broken wire, bad switch etc.
Lots of stuff for you to think about.

Update on the Yanmar 4300 fuel / timing issue. I fabricated a device to hook up to the #1 injector pump outlet. I followed the directions and found that the timing mark was off by about 3/4 inch. Following the books directions I removed one thin shim, cleaned off some old gasket material to get a true flat surface and rechecked the timing for fuel shut off. Close to perfect! Gonna leave it alone. Bled the fuel line, injector pump and the injector lines. Still no running engine. I removed the injector assemblies with fuel lines attached, pulled the compression release and checked the nozzle spray patterns. Only nozzle squirting fuel was the #1 nozzle and not an atomized pattern. Removed the other two injectors and found them stuck. Cleaned them up and checked the spray pattern again. Now I had poor fuel spray coming from the #1 and #2 nozzles. No fuel at #3 nozzle. I removed all three fuel lines from their respective injectors and cranked the engine to flush the lines and check for fuel delivery. I suppose I should mention this is my first attempt to ever work on a diesel, and it has been a learning experience. The fuel coming from the #1 and #2 lines only amounts to a drop per cycle. The #3 is less than that. The fuel rail is not stuck and moves freely with the throttle movement. I put all three injectors back into the head with only the #1 and #2 nozzles discharging any fuel. I released the compression release and tried to start the engine. WOW! it fired up on 2 cylinders for about 30 seconds and then died. Pulled the injectors again and had no fuel coming from any nozzles. None were stuck this time. It appears that the injector pump is not producing enough pressure to spray the nozzles. As I said I have never worked on a diesel before. Can someone tell me what kind of fuel pressure I should expect to see being delivered to the injector?
Sorry to be so long winded but I have tried to describe completely to better help diagnose.
firefighterfox

 

[doxford jim]

A couple more things that might affect you fuel injection performance.

The fuel injection pumps usually have a check valve on the top of the barrel - just below the outlet to the injector line. These can be no more than a conical disc shape with a flat seat and a spring on top to close the valve after the pressure has dropped low enough. These little check valves wear and the seats pit - sometime small bits of "stuff" get stuck under the seat, preventing these from closing properly. You only have three, so it would be important that they work properly as it makes a difference to the fuel injection pump operation. A fiddly job but often makes a big difference to the pumps operation.

Fuel injection pressures vary with the makes, running anywhere from 1800 psi to 2400 psi opening pressure. The spray should be a mist and you should hear a screech from the injector when the nozzle opens.

Lastly, do you have the means to work on the injectors ? You sound well informed on engines, so I would suggest you try taking one injector apart and look at the parts inside. If you do this, cleanliness is of the utmost importance.

The injector nozzle should mate to the injector body (depending on the type of injector as they vary a lot) and where they come together should be absolutely flat. They are lapped together with very fine grinding compound and the washed clean with diesel.

The nozzle and needle need to be checked for wear and should not be loose when together. Also the tip or point of the needle should be in good condition and again, lapped in carefully. To check for wear with the nozzle and needle, hold the nozzle at 45 degrees and the needle should slide down/out very slowly. If this happens, the clearance is not excessive and the needle should work just fine. If the needle falls out quickly then the nozzle and needle are too worn to use. The clearances for these are very fine and if you hold the needle in your hand too long it may not fit back into the nozzle (expands with the heat from your hand).

If you have the yanmar book it might detail some of the parameters for you. It might also pay you to spend a few hundred dollars on new injectors either from the dealer or a fuel injection shop. If you go this route DO NOT use reconditioned injectors as they are old injectors that have been worked on. New is the only real way to go. I would expect that they would cost around $400 for new injectors and new copper seal rings etc.

Good luck - sounds like you have narrowed down your problems to basically injectors !

Please let us know how you made out.

One other thing - is there an inlet filter or screen on the injection pump ? If there is a screen it could be that it is so dirty that the pump cannot do it's job properly. On my F250 diesel, the Stanadyne DB2 fuel injection pump has a conical, fine mesh metal screen on the inlet from the fuel filters. These can and do get plugged with debris.

 

[doxford jim]

I have just found this thread that probably deals exactly with your situation. Read it through as it might help you understand the workings.

http://www.tractorbynet.com/forums/parts-repairs/158832-deere-yanmar-injection-pump-static.html

Cheers

 

[doxford jim]

I see you are down in Texas where they have high humidity and high temperatures at times, for extended periods of time.

I should have mentioned this before (getting old and slow) but if this tractor has been sitting with the fuel tank only partially full, it had a chance of accumulating water from the moisture in the air. This can and often causes bacteria to grow in the fuel. Usually a slimy looking brown colour that smells strongly (similar to yeast). This bacteria (aka as bugs) can plug up the fuel filter quickly and make the fuel injection system inoperable.

I don't know if you have done it yet, but I would suggest empty the fuel tank completely and clean it out thoroughly. Usually there is a shut off just at the fuel tank - if that is the case it will make it easy to empty. Put the drained fuel aside as you really don't want to reuse it. If there is a metal screen filter on the tank outlet, take it out and clean it thoroughly. When you are satisfied all is well,put it all back to gether and refill with new clean diesel fuel. Also add fuel treatment and some biocide to kill of the bacteria.

The very fine grinding compound I mentioned above is what is known as "jeweller rouge" and is all that is needed in most cases. Straight diesel fuel will help in seating in the needles and nozzles. Extremely important to be meticulously clean and the clearances for fuel injection equipment range in the 0.0001" range.

A company I have dealt with that is very good is:

USDiesel - diesel fuel injection parts, tools and equipment,
Fort Worth,
Texas.
1-800-328-0037
email: service@usdiesel.com

Google them and you will probably find them able to supply what you need.

Cheers