whodat88

Thanks for all the input, much appreciated. I guess first I'll wire direct to the battery with a 20A fuse and see if the current draw is high. If not, wire the pump via relay which at the least would give non ECM power to the pump which seems like a no brainer. Back last summer when I changed the VP44 and my third raptor (ugh!) I had the ECM flashed at the dealer. I wonder if the reflash had anything to do with this. I keep thinking "no, it can't be the raptor pump, they have to have gotten their s**t together by now".

Thanks for the responses. To answer comments and suggestions: Yes, when I start the truck, the Raptor gets power for about 25 seconds, the same as if I just bumped the starter to check it's operation. That's it. I have a FP gauge and after this initial startup I see pressure up till this 25 or so second mark, then it falls to 0 and the truck slowly dies of fuel starvation. It's like the pump is only getting power at the start-up "key bump" phase, then nothing. Yes, as it seems to be the only problem presenting, I do intend to install a relay as it seems a good idea anyway to avoid spiking the ECM, which may be the cause of this in the first place. Where do I run the power for the relay from? If the ECM is not supplying voltage to run the pump after a short time, then the ECM connection won't work. I guess just from a key on connection.

Hi guys, I looked through the topics on this forum and didn't find anything specific about this. I have determined that my Raptor pump functions only for the first 15 to 30 seconds after startup, then quits. I hotwired it to the battery and it works fine, so it seems to be a power interuption to the pump causing this. If this is true it doesn't seem that a relay would solve the problem, as the same power interruption would interfere with power to the relay. Could this be some sort of ECM issue, or maybe just a ground, or reflash needed? Any suggestions would be appreciated!

Thanks you guys. What a wealth of knowledge I tapped into to help with this project. And Mike, thank you specifically for building and maintaining this site. Incredible resource!

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?

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.

I'm changing the pump today, and hopefully will have good news. Cycled the LP a lot yesterday in different conditions and have seen a fuel pressure rise every time.

I did not have a pressure gauge working for the past 6 months or so, only a low pressure warning light probably not low enough to trigger the light. Seems a case of a failing Raptor taking out the VP.

I had erased the previous codes after checking Friday PM. I checked the codes and have P0230, P0216 and P1693. The wiring looks fine, nothing weird seen.

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.

OK will do. So my $1500 question to you guys is: have you experienced this sort of issue before, a seemingly functional VP44 except upon starting? I would like to be reasonably certain that changing this will repair this.

That's what I was thinking...I think I have a combo problem. Intermittent power to the Raptor, causing excessive wear on the VP44, to the point where the VP44 is not creating enough pressure to pop the injectors. Mike, do you know where the ground is for the Raptor/stock lift pump. Might be worth checking on that. Once I determine the cause for intermittent operation of the Raptor and repair, then I think I'll have to bite the bullet and change the VP44, as earlier even with fuel pressure from the Raptor it wasn't getting the engine to fire without a higher RPM than the starter could provide.

Yeah I was looking at the exploded parts diagram and saw that...I pulled the overflow valve and cleaned, didn't matter. However when I went to start after this I had no fuel pressure, and bumping the starter did not cause the Raptor to run. It's a bit too hot out there now to continue, so I will continue this later this afternoon.

There must be a check valve somewhere near the inlet of the VP44 to maintain pressure in the pump, right? If that were going bad or sticking this would be the result.

To answer your last question first, it had the pump mounted on the left side of the engine, where the Raptor is currently mounted. I started the engine, psi at idle is over 15, drops to around 12.5 upon reving up to 2200, then settles first back to around 12.5 then up to 16. I cracked the injector lines of 1,3,4 while running, didn't think this would matter, and of course got a little rough idle when one was cracked, and smoothed out after tightening. After this fuel pressure check I shut the engine down and immediately tried to restart without starting fluid, no joy. I've got plenty of starter speed, but it just needs that little extra from the fluid to work. Anything I can do to stop the bleed down of the pressure in the pump?