Case 680E

[DavidBarkey]

@Eugen I can't remember . Did you get the injectors rebuilt ? The other thing besides compression is the injector pump . This unit uses the mechanical pressure to over come the injector . #4 pump segment my not be producing enough pressure to overcome the injector .

[Eugen]

@Eugen I can't remember . Did you get the injectors rebuilt ? The other thing besides compression is the injector pump . This unit uses the mechanical pressure to over come the injector . #4 pump segment my not be producing enough pressure to overcome the injector .

Yes, injectors were done at the shop in Toronto. I wish I could switch the pump lines but they are steel. Easy to switch the injectors but the tractor was running like this before too, plus the injectors were out and calibrated. One thing the compression test can do is confirm the problem is with the injection pump.

If I could find a fitting to connect a 5000 psi dial to the pump I could see if that is the problem. The injector opens up at 3200 psi as per spec.

[DavidBarkey]

@Eugen I can't remember . Did you get the injectors rebuilt ? The other thing besides compression is the injector pump . This unit uses the mechanical pressure to over come the injector . #4 pump segment my not be producing enough pressure to overcome the injector .

Yes, injectors were done at the shop in Toronto. I wish I could switch the pump lines but they are steel. Easy to switch the injectors but the tractor was running like this before too, plus the injectors were out and calibrated. One thing the compression test can do is confirm the problem is with the injection pump.

If I could find a fitting to connect a 5000 psi dial to the pump I could see if that is the problem. The injector opens up at 3200 psi as per spec.

It would be easier to test the injector pump than compression . At that point you can do all 4 to see where you sit . When you were working on the transfer pump did you pull the side cover off and access the pump cam condition ?

[Eugen]

It would be easier to test the injector pump than compression . At that point you can do all 4 to see where you sit . When you were working on the transfer pump did you pull the side cover off and access the pump cam condition ?

I did take the side cover off but could see nothing out of the ordinary.

If I had the right fitting to connect a dial to the pump I could test the pressure. I think it's compression fitting on the pump side but not sure. The gauge is probably 1/4 npt.

[Eugen]

As I don't have a way of hooking up the pressure gauge to the injection pump, I'm thinking of a different way to test cylinder 4 of the pump, like this: hooking up injector number 4 to the line, but upside down, that is, pointing up in the air, instead of into the engine, run the engine for a little bit, and observe the spray pattern. Here's where I lack experience, but for a diesel cylinder not to fire at all because of poor pressure or bad injector, I would expect to see some pretty poor spray pattern from the injector, right?

What do you guys think?

[Eugen]

Well, it's amazing what you find on the internet. Here's a blurb relating why it's a bad idea to hook up a gauge directly to one of the injection pump's outputs:

Injector pumps are positive-displacement things, so you absolutely must have a way for the diesel to get out. If you stuck the gauge directly to the end of the line you'd break something. Probably the gauge, but no guarantees it won't ruin the pump. You cannot tee-in to the fuel line either. Besides the lines being too stiff for you to make room for the tee, the volume of that line is calibrated. Changing it will throw off the pressure your fuel pump develops when injecting, so your measurements will be meaningless. If the pump cannot develop enough pressure to run the injectors due to wear you'll have hell even starting the engine. But that shouldn't ever happen unless it's been fed bad fuel. Your pressure is controlled by the injector needle, not the pump--it just builds pressure until that needle gives. Before pulling the pump what you need to do is bench-test your injectors as another poster described. Or test them in the engine: If your problem is rough running from a single bad cylinder, then with the engine running, crack each fuel line loose (one at a time) and see if diesel fuel is spilling out to make sure that cylinder is getting fuel. Crack it at the injector end, so you don't wind up letting an air bubble into the fuel line. You may even let out an air bubble in there already. Also listen to the engine, if there is no change to the engine sound/RPM when you crack it, or you start with a loud hammering sound that goes away when you crack the line, you've isolated the bad cylinder. Swap that injector with any other injector in that engine and run the test again. If your problem moved when you moved the injector, the injector is bad--replace or rebuild it. If the problem stayed in that cylinder, then you either have a problem in the pump or you have a mechanical problem, like a valve setting. Do the usual mechanical checks on the engine. If the engine's good, it's the pump. Once you narrow it down, you can decide what to do. Checking the pump's performance any further requires some hideously expensive equipment and is done off the engine. If you find a problem with the pump you might as well pull it and take it to a pump shop for a rebuild.

But, my idea of hooking up the injector upside down, seems like it's not bad. Here's another blurb found on the net:

I have worked in a fuel pump shop for 15 years diesel pumps really work on volume of fuel depends on load and speed ,if your motor starts and runs / idle smooth the pump is in pretty good mechanical condition if it is hard to start hot or cold and the motor is in good condition ,compression , timing etc the pump elements are worn out through dirty fuel a simple test to check pump elements remove an injector from motor and turn it up side down replace it back on the injector pipe (don't worry about the return pipe let it flow to the floor /container ) crank the motor over and watch the spray patten (in the run position ) KEEP HANDS AND BODY AWAY FROM DIESEL SPRAY , DIESEL IN YOUR BLOOD STREAM YOU DIE QUICKLY the spray should be an atomize spray ( not like an oil can) to check for a miss undo one injector pipe at a time if you find a miss swap the injector to an other cylinder and see if the miss follows the injector the best thing to do is remove the pump and have it tested on a test bench and reset to the test data

[Timj]

What's the problem, you don't need 4 cylinders, my Ford only has three and works just fine. well works fine except for the starter solenoid that burned up on the job last week. really fun fixing stuff out on the job. it's always something.
doing your homework you'll get it figured out. Keep your chin up.

[DavidBarkey]

@Eugenhttps://www.princessauto.com/en/adjusta ... 1000000778
something like this mounted between a guage and the pump with the releaf plumb in to a catch can . Then you could see what the unit is capable of. the inject is basicly a releaf valve

[Eugen]

@Eugenhttps://www.princessauto.com/en/adjustable-reli ... 1000000778
something like this mounted between a guage and the pump with the releaf plumb in to a catch can . Then you could see what the unit is capable of. the inject is basicly a releaf valve

Thanks Dave, I gotta squeeze my little brain a little here. So if I get this valve, then adapters/fittings to couple the gauge to this and to the output of the injection pump, and possible high pressure hose, it's gonna be some headache figuring it all out. It's an interesting exercise, but I wonder if it's worth it; it'll cost at least $100. Found a diesel compression tester kit that I think fits this tractor, for $156 CAD delivered to the door. I'm leaning more to getting the compression tester.

@Timj that's right, who needs a stinkin' forth cylinder when three already do the job?! but when time comes to sell it it'll sound better running all four. Plus one of the wheels isn't going round and round as it should, it's probably connected to that cylinder! he he! By the way, I'm using a P100 half face 3M mask when operating the backhoe. Can't stand that smoke.

[propane1]

Just drill a hole in the head Eugen. Install a spark plug. Run gasoline to it. Have a monetary switch in the cab. So you can fire the cylinder, when needed. Problem solved.


Aren’t I some helpful, hmmmm.

Noel