Ok,
I also have a QUADZILLA COMMANDER. Well about 10 days ago I noticed (on COMMANDER) that my fuel PSI had dropped dramatically from the usual 13-14psi, down between 0 to 9. The COMMANDER showed the fuel PSI fluctuating wildly (I have the QUADZILLA fuel sensor "canister". I know its a poor design, but it seemed to work alright.)

I also have a RAPTOR 150 pump (installed in Oct).

Well, let me tell you what I've done...sorry if this is a bit long.

In order to rule out the potential dreaded VP44 I've ordered a mechanical fuel pressure gauage from Geno's. Its in the mail. When it arrives, I'll remove the quadzilla "canister" and check out the reading mechanically vs the COMMANDER.

NOTE: When I put the RAPTOR on in Oct my fuel pressure (per COMMANDER) went from 4-7, up to 11-13.

Before the COMMANDER started showing the fuel psi fluctuating wildly, the truck was running perfectly--no misses/hesitation/stalls; normal normal.
Nonetheless, I didn't hardly drive it after the fuel pressure indicator dropped to zero-ish.

So, I began checking all the fuel line connections from the tank to the RAPTOR to the fuel filter up to the COMMANDER "canister" (ensured the connection nuts were secure, but I tweaked the tightness anyway)...

WAIT--THE FUEL FILTER!!! I checked my records and found I had not changed the filter in rougly 10,000 miles. So, bought a fuel filter. Then I got me an empty bottle (clear) and first drained the filter-housing (from the 'water in fuel' switch/hose). I didn't notice any water, but the fuel
cansister drained about 9oz of "urine"-yellow fuel/liquid (sorry for description). Then I got another clear bottle and poured some clean diesel from
a spare can of fuel I keep. The "new" fuel was a clear-blueish color. Not sure if that makes a difference, but I noted it. (see photo comparison)

I installed a new fuel filter (Luberfiner brand), refilling the canister with clean fuel.

ALSO, I adjusted the RAPTOR FUEL PUMP, increasing the pressure 1/4-turn (for my peace of mind).

ALSO, I used my hand-held scanner and checked for any codes in the computer: ZERO codes.

ALSO, I re-downloaded the last COMMANDER software update (version 1.4.9) from the website and followed the instructions to update the COMMANDER.

I tapped the key 2-5 times to prime the fuel.

Then I started the truck.

FUEL PSI now shows a steady 16psi !!!

So, I'm really really really hopeful that the VP44 is NOT failing. I drove the truck about 20 miles throughout today and the COMMANDER is
consistently indicating 14-16PSI (depending if I mash the peddle or set the cruise control).

I'm very interested in any comments or thoughts from the experts here.

NOTE TO ANY QUADZILLA OFFICIALS: I've sent basically the same msg above to the cust service department. No real complaints, just interested in thoughts about my self-diagnosis.

 

I don;t see any driveability, starting issues, smoke issues, dead pedal, codes or any of the other hallmarks of a dying VP44 in you post.

Making sure you have adequate pressures with a good fuel supply is about all you can do until you have a failure.

Dave

 

Thanks Fishin. Fuel supply is good; after I changed the filter, I put the filter cap back on, but didn't screw it down tight. Then, like I said, I tapped the key a few times then I checked the cap--needed quite a few paper towels so supply is good. Thanks again for the re-assurance. -d

 

It only takes one bad batch of fuel to take out a filter, hence the reason to have a fuel pressure gauge of somekind. Personally I keep a spare set of filters, and tools to swap filters in the truck. because you never know when your going to need it, or have to change it on the side of the road.

My old set up had mech gauges and low pressure lite, now I only have an edge monitor, but I did "T" in my edge sender so I'm going to go to the cummins dealer and get the Low pressure sender (20$ sender only) to have as a way of confirming fuel pressure, if the light trips and the monitor shows under 5psi its pretty much a given I have no pressure, if only one or the other shows low pressure then it would be a sender issue. I'd perfer a mech gauge but dont want to mount it in the cab again especially since I have the Attitude pillar mount

 

NICK
I'm not that familiar with the Edge set up (familiar with the Edge in general, but not detailed set up). You say "T" in the sender...hhmm. The Quadzilla fuel sensor is a small "canister" that you attach a wire to in order to get a signal; it mounts in place of the measurement connection near the VP. I'd like to have another mechanical method/connection to obtain a measurement. There was a port on the side of the fuel filter cansiter, but the RAPTOR pump line feeds directly into that port. I'm not familiar with the "low pressure sender (cummins) that you described; I think I want to do the same, but will need a bit more education. I have seen the low pressure light; decline for now.

 

I think your VP will be fine. They are one of those things that aren't dead until they're DEAD! Then you will have the signs of failure. FWIW, before I did things the right way with a FASS, I used a Holley Blue. I had 3 failures resulting in a completely dry pump as well as a previous 100k miles on the weak factory pump. I can think of at least 5 times my pump had gone dry due to various reasons. Not until after the third Holley failure did my VP go dead.