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Do I need a new VP44?


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Mike....What do those solenoids control, (Metering solenoid and shut down solenoid); do they control INJECTION PRESSURE AND DELIVERY TO INJECTORS??

 

what about the timing piston, if its stuck in the advanced position wouldn't it create difficult starting???

Edited by rburks
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So this morning I went out and bumped the starter about 20 times, and got fuel pressure every time.  Just came back from running around and tried it again about 5 times with no problem.  So I think the Raptor is functioning ok.  Maybe it was just tight and needed to run a bit, don't rightly know.  However I cannot get the truck started using just the starter, even with good pressure to the VP44, and it will run using ether, so I think the VP44 is not providing enough pressure to pop the injectors.  I am going to pull it this afternoon after I get some shade.  In the meantime if anyone has any revelations regarding this please let me know. 

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AT THIS POINT IM PRETTY SURE THE PROBLEM IS IN THE VP INJECTION PUMP.... Don't know exactly where, 

 

  Im interested to see what Mikes has to say, HE knows the inner workings of the VP rather well

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    Yep, at this point I'm inclined to agree that the VP44 is TOAST.. As to the cause its hard to say IT was for certain the RAPTOR sense you have not had pressure gauge working. If you could say yes"FUEL PRESSURE IS LOW  AND HAVE HAD  ISSUES With fuel psi fluctuating  and dropping at random then yes i wouldn't hesitate to point the finger at the Raptor. you have described a couple of instances here in the last few days of loosing power to the Lift pump to intermittent short in LP circuit.... 

 

  BUT having said that, I'm convinced that your VP is bad, but you may still have issues in your LP circuit

 

  To answer your question, i have seen instances where VP would result in hard difficult starting.

 

In the future maintain a working Fuel pressure Gauge. this will assist you and others in trouble shooting issues with your truck 

Edited by rburks
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  • Owner

Mike....What do those solenoids control, (Metering solenoid and shut down solenoid); do they control INJECTION PRESSURE AND DELIVERY TO INJECTORS??

 

what about the timing piston, if its stuck in the advanced position wouldn't it create difficult starting???

 

There is only 2 solenoids on the VP44.

  1. Fuel Solenoid
  2. Timing Solenoid

The fuel shutoff signal just shuts off the power to the fuel solenoid and it stops running. Excessive timing will make it hard starting. Depends on what the OP's starting pressure is too. If the cranking pressure is between 7-12 PSI which is normal. Above that will create timing issues. The ECM has a 50% duty cycle on the lift pump to reduce fuel pressure this is one reason why we need to keep the ECM control of the lift pump. Now another test would be disconnect the lift pump and see if it starts easy if so then the cranking pressure is too high.

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There is only 2 solenoids on the VP44.

  1. Fuel Solenoid
  2. Timing Solenoid

The fuel shutoff signal just shuts off the power to the fuel solenoid and it stops running. Excessive timing will make it hard starting. Depends on what the OP's starting pressure is too. If the cranking pressure is between 7-12 PSI which is normal. Above that will create timing issues. The ECM has a 50% duty cycle on the lift pump to reduce fuel pressure this is one reason why we need to keep the ECM control of the lift pump. Now another test would be disconnect the lift pump and see if it starts easy if so then the cranking pressure is too high.

 

Where does the shutoff signal come from???   and i thought the timing advance was merely the Timing Piston and sleeve that controlled timing, where does the timing solenoid fit into this???

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  • Owner

Where does the shutoff signal come from???   and i thought the timing advance was merely the Timing Piston and sleeve that controlled timing, where does the timing solenoid fit into this???

 

ECM sends the shutdown signal.

 

ecm3.jpg

 

As for timing solenoid its a hydraulic valve that send pressure to one side of the piston to advance timing or vent the pressure to retard again the return spring.

 

timing-piston.jpg

 

kd93f7.jpg

 

1q6an9.jpg

 

You can see the 2 solenoid connectors off the PSG. One is timing and one if fuel pin.

287iuc0.jpg

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I changed out the VP44 today and the truck started right up.  I think I've learned how to prime now, LOL!  I have a drip from the VP44 inlet somewhere, most likely from the brass fitting for the fuel pressure gauge sender which I'll attend to tomorrow.  Quick easy question...I received the rebuilt pump with 2 crush washers on the pressure relief valve, fuel outlet which I know are to put on each side of the banjo fitting, however there were also two washers inserted around the plastic plug for the fuel inlet, which reminded me that originally i had some sort of banjo there. Now I have a fitting with an O-ring that mounts to the pump, and a swivel that attaches to that, all of which I installed when I originally installed the Raptor.  This O-ring seal seems not quite right....to tighten down on the fitting crushes this O-ring to deformation.  Is there a better setup available to mount the inlet hose to the VP44?  This is where the drip is and I might as well change it now if it's something locally available.

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ECM sends the shutdown signal.

 

ecm3.jpg

 

As for timing solenoid its a hydraulic valve that send pressure to one side of the piston to advance timing or vent the pressure to retard again the return spring.

 

timing-piston.jpg

 

kd93f7.jpg

 

1q6an9.jpg

 

You can see the 2 solenoid connectors off the PSG. One is timing and one if fuel pin.

287iuc0.jpg

 

GEEE MIKE...Your a walking VP44 DATABASE :woot:

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If you have installed the "BIG LINE KIT" it should look like this

The fitting is identical to the one shown except I have an O-ring instead of that big washer.  That washer is what I need.  Do you know where I can get one?

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  • Owner

GEEE MIKE...Your a walking VP44 DATABASE :woot:

 

It took me over 5 years of asking around to get my hands on a damaged VP44 that couldn't be used as a core and it just happen to be Rev 027 as well so it most common version of pump. Now if we could get people in the CR group to pull apart stuff too. :wink:

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The fitting is identical to the one shown except I have an O-ring instead of that big washer.  That washer is what I need.  Do you know where I can get one?

Vulcan performance,, there a vendor here,, just look over in the vendor articles

 

 

Here you go, this should be what you need

 

http://www.vulcanperformance.com/Bonded-Sealing-Washers-12mm-p/sw12.htm

Edited by rburks
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