Raptor Lift Pump Issues?

get rid of the raptor and see what happens..rule out the pump...hell hang a bottle of fuel from the hood into the vp to run it and see what happens..all it needs is positive pressure for a few mins to see if it works..it wont kill the vp for that long and you can rule out anything to do with the raptor then
 
VP44 Raptor Pump issues - YouTube

Ok. I found a gauge with a smaller range today that I know works. I ran out of fuel in my 5 gallon can so hooked the tank back up. One thing today that I hadn't noticed, is there is obvious sucking of air when running without the lift pump. I think maybe there is a bad seal on the Raptor pump outlet. As you can see in the video, as soon as I connect the Raptor pump to the battery at 7 seconds in I get immediate cavitation, but then it subsides and clears up with zero bubbles; way better than even before. BUT the engine still keeps missing and doesn't ever clear up. The gauge showed 20psi when I initially put it on, adjusted the Raptor pump down to about 10psi; engine still runs the same.
 
After all this diagnostics and deliberation. I believe that my injection pump is bad. Something that I noticed for the first time today (and you can see it in the video), when I bleed injectors 2, 3, and 5 I get a nice crisp squirt of diesel. When I bleed injectors 1 and 4, I get a stream of diesel along with the occasional squirt. From what my research has told me, the (plastic?) diaphragms or seals between the high pressure and low pressure side of the plungers are cracked and this allows fuel to push passed and right into the high pressure side and thus the injectors. You don't notice the issue without the lift pump running because there is no positive pressure on the low pressure side of the pump.


Does my conclusion make sense?
Kris
 
that is strange....I would have to go with the pump as well....not much else to logically make it do that except huge connector tubes
 
I tore the injection pump down last night out of curiosity. I actually had a solid steel diaphragm; not plastic, or steel covered in plastic Kinda weird. So no cracks, but the snap ring seat was a little distorted from pressure, thought maybe the diaphragm might unseat under pressure and lose seal against the oring? I dunno. The timing collar wasn’t froze, but the plunger/actuator looked pretty worn. I bought a good used HO pump that will be here Monday. We’ll see what happens then.
 
Good news! Got the good/used injection pump on and she's running great! I feel that this truck was a good investment. Now just need to do some research on the best way to wire up the relay for the raptor pump.

Thanks for everyone's help,
kris
 
unplug the wire off the stock pump and use it to trigger a relay to run the raptor..easy..and protects the ecm from overload. pump will prime and start the truck at low pressure as well
 
thatguy69 said:
Is there any good documentation on rebuilding a vp?

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I actually probably could have rebuilt mine as after digging in further I found that the timing collar was seized way advanced and that was the cause of the issue. Some deburring and lapping could have fixed it. But I didn't take the shaft out in the right order and in the process, pressed the timing toning ring off the shaft; it would have been a pain to try and recalibrate the timing.


Its not too difficult to take apart, and if someone found the same issue as mine; definitely fixable with someone who wants to take the time to do it. If anyone is interested, I do happen to have a good brand new rebuild/seal kit for a VP44. I'll sell it for $40.

Kris
 
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