Testing a Bosch VP44 Pump for a Cummins Application
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- čas přidán 6. 11. 2022
- Testing a VP44 injection pump requires a Bosch EPS815 calibration test stand with the proper adapters. In this video, we show the steps for calibrating the VP44 injection pump, calibration or programming the PSG (black box on top of pump), and installing the correct timing key.
Some items to note:
A new PSG is blank from the factory and must have the proper calibration "burned" into it on the test stand, based on the injection pump part number.
The proper timing key is installed after the calibration procedure, with the arrow on the key pointing toward the injection pump. The key is offset to adjust for slight variations in tolerance for base timing.
The loop on the housing, on the mounting surface, is used to verify timing, don't pry on it during pump removal.
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Can you tell us whether or not excessive lift pump pressure is still an issue? I've read the diaphragm can be damaged by excessive lift pump pressure? I was told nothing above 22psi. We also discussed that it should never go below 14psi to keep the overflow valve open to ensure fuel constantly circulates through to keep it cool. What's your thoughts?
1. Excessive lift pump/supply pump pressure can cause problems with starting. The higher the lift pump pressure, the higher the housing pressure is, which can result in reduced fuel delivery at cranking.
2. The old style diaphragm cracks due to severe fuel pressure pulsations, caused by aeration in the fuel. The new style diaphragm is thick and more robust and normally does not crack. However, with severe fuel pulsations, it can damage the o-rings that seal it. Extreme tuning can also cause the pulsation dampener to wear the o-rings due to the stress of absorbing the fuel pressure discharge of each injection.
3. 15 - 18 psi is plenty of fuel pressure, unless you have an extreme demand. As long as it stays above about 4-8 psi under hard acceleration.
4. On the test stand, the pump is feed 30 Kpa supply pressure, which is just under 5 psi. The supply pump internally in the injection pump creates enough pressure to open the overflow valve and have plenty of return fuel for cooling. Running less than 1/4 tank of fuel in hot weather can create heat issues, because you have lost your "heat sink" by having less fuel to dissipate the heat from the return fuel.
What port was being used to measure case pressure, as well as what was being done when hitting the regulator?
There is a port above the fuel delivery outlets, where transfer pump pressure is measured, on the test stand. The case - or housing pressure is not measured however, the return volume from the pump is measured during testing. "Hitting the regulator" would increase transfer pump pressure. If the transfer pump pressure is too far out of range, it will affect the timing advance.
Could you please explain the purpose of the key alignment tool?
Hello Bruce,
The timing blocking procedure is performed by the test stand, and then the pump is locked in time. There are 29 different keys to adjust for minor tolerance differences with pump components. We select the exact key so the key alignment tool aligns with the hole in the housing. If the pin does not engage properly, then we change the key (different offsets) until it does. This properly sets the base timing.
What are all the cause of the vp44 going bad on there Cummins 5.9 ISB
In order of occurrence, the main failure is aeration into the pump, which damages the advance piston and pump housing advance bore. Then a mix of water contamination, the old style diaphragm cracking from air in the pump, PSG controllers failing (computer on top of the pump). Along with speed sensor issues, and fuel control solenoid failures.
@@oregonfuelinjection thank you is, my fass pump ended up stop working due to relay going out, drove it around for 3 days, it’s smoking well light blue with white smoke now , if I accelerate if gray smoke, this is after me filling up the truck
@ohn7367 You did fuel up with diesel correct (sorry we see this often), and you have the FASS pump working now, correct?
Do you have any codes? It is possible that the advance area could be damaged from air in the fuel when the FASS pump quit working. Give us a call for additional diagnostics or take a look at our online diagnostics oregonfuelinjection.com/services-repair/diesel-diagnostics-repair/dodge-diesel-diagnostics/#98
@@oregonfuelinjection yeah it’s filled up with diesel. And the fass pump started working,it started to miss at 1500rpm. No codes still for some reason. I send out the injections and the tested out good to go. It’s blue and give gas it’s more gray. It was running good before the fass pump went out :(
It’s not oil because I’m not loosing oil or it don’t smell like oil more of rich fuel.