IH 500 C Injector pump help

Need to know how the injector pump works.
New to diesel stuff.
Is the pump driven off of the pulley belt?
What kind of pressure should I have going to the injectors.
I have an inline fuel pump. I can't get any pressure on the injector lines. There is fuel there. I cracked open the line.
The fan belt is really loose. Could this be the no pressure problem.
The dozer turns over good. New starter.

I don't know the specifics of the pump you've got, but in general, the injection pump is going to be driven by the gear train in the front of the engine, so it stays timed with everything else. In other words, a loose fan belt has nothing to do with your problem.

As far as how the pump works, most inline pumps are going to have plungers (ie-piston pumps) that operate off of a cam shaft to pressurize the fuel. Most older pumps are going to be putting out somewhere in the 3000 psi range, give or take.

In operation, the pistons/plungers are operated by a rack gear, controlled by the governor, that turns them to vary the amount of fuel they pump, in relation to the speed/HP requirements of the engine.

Usually what happens, if the engine has been sitting, is that the rack will stick in the 'no fuel' position causing no fuel to be delivered to the injectors. Dependent on the pump, some, like the old Simms on my 3500 Ford, also have tappets that run against the cam, and in turn cause the plunger pumps to pump. In that case, the tappets can stick in their bores and cause a no fuel condition, even if the rack is free. I know this because I just had to go into mine and repair that problem.

Like I said, I don't know the particulars of your pump, but in general this is how they work. Hope it helps, and good luck.

Wayne has got you going but are you sure you have the on off lever in the proper position. How long has it been since the unit ran?

pump is gear driven so fan belt not the cause--the 500c has 2 fuel filters--primary and secondary so make sure they are clean---bleed the system until you get all the air out as this will affect the injector pressure

The unit has sat for about 2 years. I had to fix a broken fuel line, bad starter, and an inline fuel pump that didn't run. Where are the filters on the injector pump located? Will tapping on the inj. pump help to get the parts that are stuck working? Can these be rebuilt or will they need replacement Thanks for all the help

The inline fuel pump you are referring to is the feed pump and not the injector pump,as far as I can recall the D155 3 cylinder engine had a Bosch rotary pump,some people changed them over to a CAV rotary,when you fixed the line and the feed pump you let air into the system,you need to bleed the system to get rid of the air,open the bleeders on the filter/s and pump,switch on and the electric pump should push fuel through the filters,close the filter bleeder/s first and pump last,some pumps do not have a bleeder they bleed back through a pin hole in the return,find the return line from the pump and loosen that banjo bolt so the fuel can get out,switch on again,fuel should flow from the return,tighten the banjo bolt,loosen the three injector pipes at the injectors,on full throttle with a good battery in crank the engine over till fuel spurts from the pipe unions,tighten them up and try for a start,if you have to come back get the numbers off the injector pump so we will know what you got.
AJ

Thanks AJ. Will try it this weekend. Have to work Mon-Fri. during day. Will get back to you guys this weekend. Thanks again for all the help.

Still can't get fuel to injector lines.
Getting fuel to (I aasume)the return line.It is the highest point on the pump. No fuel is coming out of the 3 lines going to the injectors. The on off looks to be ok. I ran the inline add on fuel pump and also tried to start it. No go. What could be the problem? Thanks again for all help.

I am not sure if you have bled the pump at the return line,there are five pipes attached to the pump,three are high pressure injector pipes,the feed and return are the other two,one the feed is connected to the filter,the other is the return,trace it and you will find a tee,the tee has the leak off from the injectors,the return from the pump and the line going back to the tank,open the banjo fitting at the pump and switch on till clear fuel comes,tighten the banjo bolt and crank the engine over again,if no fuel spurts from the injector lines it possible the fuel shut off is stuck in the stop position,get a second person to operate the stop control,watch it,when the cable is pulled the lever will move,when the cable is pushed back see that the lever goes against its stop,push it back with your hand if not and crank it again,as you are not familiar with diesels to get a mechanic to have a look at it would be the way to go.
AJ