Testing a VE pump
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From: Jacksonville, FL
Testing a VE pump
Is there any way to test/check the proper functioning of the VE pump without removing it? Having some fuel issues that I'm going to start another thread about but this is just the question.
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Can't say i have ever come across any info that designated a way to test the function out while on the motor. But perhaps a factory cummins or Bosch VE manual would have a series of procedures to do this?
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You can test case pressure, that might tell you something, but from the other thread I'm 98% sure your pump needs to come off. Right way to do it would be pull it and take it to a rebuild shop, but it is possible to do a tear down & inspect on a VE pump in a home shop as long as you're very careful. Woln't be a true rebuild but could show obvious problems.
My bet from the other thread is that you have a fuel transfer pump or supply issue within the pump. The Ve pump contains a vane pump in the front of the case that boosts case pressure to around 75-125 psi depending on rpm. This pressure actuates the hydraulic timing advance and supplies pressure to fill the pumping chamber - the external supply pump just delivers fuel to the injection pump, it alone is not enough pressure to actually fill the chamber. There is also a regulating valve assembly that could be sticking.
Testing pump pressure requires a pressure gauge that goes up to 200 psi or so and a tee setup. What you do is remove the return line banjo bolt, connect one leg of the tee to the injection pump and then fit the other end of the tee so it flows through the banjo bolt and to the return line.
The return line banjo bolt is actually a calibrated orifice that give s a flow restriction, so by doing this you can monitor the internal pressure. Also inspect the orifice and make sure it's clean - it's very small, on the order of 1/32" and must be clean.
I would expect to see 75 psi or so at idle up to 125-150 at max rpm, and this should vary fairly smoothly with rpm. May vary some with load too, I don't know if these pumps are setup that way or not.
My bet from the other thread is that you have a fuel transfer pump or supply issue within the pump. The Ve pump contains a vane pump in the front of the case that boosts case pressure to around 75-125 psi depending on rpm. This pressure actuates the hydraulic timing advance and supplies pressure to fill the pumping chamber - the external supply pump just delivers fuel to the injection pump, it alone is not enough pressure to actually fill the chamber. There is also a regulating valve assembly that could be sticking.
Testing pump pressure requires a pressure gauge that goes up to 200 psi or so and a tee setup. What you do is remove the return line banjo bolt, connect one leg of the tee to the injection pump and then fit the other end of the tee so it flows through the banjo bolt and to the return line.
The return line banjo bolt is actually a calibrated orifice that give s a flow restriction, so by doing this you can monitor the internal pressure. Also inspect the orifice and make sure it's clean - it's very small, on the order of 1/32" and must be clean.
I would expect to see 75 psi or so at idle up to 125-150 at max rpm, and this should vary fairly smoothly with rpm. May vary some with load too, I don't know if these pumps are setup that way or not.
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