Parallel pumps for a VP44?

[jalex]

Has anyone hooked two lift pumps in parallel to have a back up fuel supply on the VP44? I think I would put the auxiliary pump close to the fuel tank as possible; but not sure where to connect in........to the outside of the main pump or possibly use the filter Schroeder valve (this would act as a check valve ? ) I have an '01 with 119,000 miles and I am ready to replace the fourth pump (Carter) . This week I had to limp in with 1 pound of pressure for 120 miles. I had a spare pump; but it was dark and I was in no mood to change the pump in a truck stop after already 650 miles that day. I would like to be able to use a toggle switch to power up the aux pump. I am going to put a different pump than a Carter on this time (finally) but would still like to have a backup. Has anyone done this to their VP44 pumps?

 

[JR]

On my 98 I installed an Air Dog on the frame rail next to the tank and installed a tee on the suction side with a pair of ball valves. Did the same on the discharge right before the engine mounted fuel filter. Left OEM Carter pump in the factory location, in the event of a failure it was a matter of opening/closing valves and disconnecting the harness that fed the Air Dog and plugged the carter pump back in. Easily done on the side of the road in under two minutes.

If I were you, I'd make the primary pump the one down by the frame rail and leave the engine mounted pump as the backup. Even if it's just another Carter pump. And run 3/8 or 1/2" lines. The factory set up has so many things working against it it's no wonder they fail so often. Engine heat and vibration and drawing through too small and too long of fuel line are all killers of electric pumps. Pumps are designed to push but when they do have to pull the suction should be sized larger than the discharge. The whole set up was poorly planned.

 

[jalex]

Thanks JR, I have been telling myself to do something after the first pump went bad in 2005 or 06; but I am terrible about out of site out mind and pay for it on the road person. I will make the side rail pump the main because of the push/pull ratio. Did you cut the steel tubing supply line ahead of the tank and install the tee and ball cocks with rubber fuel line or did you install a larger hose for the supply line at the tank? Did you just flare the steel tube or is there a more secure way to make the splice? Does your Air Dog setup have a pre-filter for the pump? It should be ok to able/disable the power to the pumps with switches should it not? I wonder if the old G.M. electric valve for the 2 side mounted fuel tanks be large enough to switch the fuel lines? Just wondering........the ball cocks would be much more reliable though. Thanks again for the input. Jerry

 

[JR]

On the steel line I used regular tube fittings where I cut the line. They crimp the line when tightened down to make a seal. I used tube to pipe (npt) fittings to adapt to the fuel line for the Air Dog. I had problems with my suction screen in the tank at one point so while I had that out I installed a draw straw.

 

[jalex]

Are the tube fittings like the compression fittings on copper tube? I will research where to get the adapters I need to do what you did. Did you put a pre-filter or did your Air dog have the block with the two screw on filters? Thanks, Jerry

 

[JR]

Yes same thing. Compression fitting on one side npt on the other. Like this.

The Air Dog draws fuel through the water separator filter and pushes through the secondary so it is filtered before going through the pump.

 

[jalex]

I had not seen this fitting before. That will be so much better for me than cutting and flairing. Thank you JR.

 

[KATOOM]

This is not a new discussion... People have tried all kinds of contraptions for supplying fuel to the VP. Dual fuel pumps was proven to be not the best idea either because of many reasons.
Pulling or pushing fuel through another fuel pump is never a good idea, and depending on the type of fuel pump used, its not always possible.
The check balls and turn valves are restrictive and can cause leaks in the fuel system. If the fuel system looses its prime then it will cause a hard start issue. And if air is entering the system somewhere then the fuel will be aerated which looses pressures and potentially lubrication value.

The best and only dual fuel pump system I'd ever consider is the Fuel Boss mechanical fuel pump which can be set up with the OEM Carter pump used as primer or back up. That said, you dont need to use the Carter with the Fuel Boss but can be reassuring for some people.

There are quality fuel pump systems out there which will prove to be much better than any DIY project. And pumping volume is just as important as pumping adequate pressure. Too many fittings and restrictions will cut the volume down which will force the fuel pump to work overtime trying to supply the pressure.

Lastly, compression fittings are illegal for fuel because they're unreliable and can leak easily. If you're caught using them in an accident then you can imagine.....
The best fittings possible for fuel lines are JIC flare fittings. The same thing as AN fittings.

 

[JR]

He's not talking about running pumps in series, he's talking about a spare that can easily be plumbed in in the event of a failure, which he's apparently had many of. A ball valve is no more restrictive than the line itself as they carry the same ID

Lastly, I have not heard of compression fittings being illegal. I doubt this is true because Dorman makes compression fittings they market as fuel line unions, gasoline/diesel compatible. See em at the parts store all the time.
I can't tell you how many guys I've seen run standard compression fittings on their nitrous setup. Nitrous Express used to sell their kits with compression fittings. Theyve worked fine for alot of years .

 

[KATOOM]

Yes, I do understand he's asking about running fuel pumps in parallel, and no, its not a good idea.

In all simplicity it would be sooooo much easier just to run JIC fittings on the fuel pump connections and have a spare fuel pump sitting under the seat instead of trying to rig up some multi fuel line with check balls and valves. Why would you want to create so many places to leak or potentially fail??? If the fuel pumps are failing so often that you need to be able to flip a switch for the next fuel pump then you best be looking for a better fuel pump, not lining them up.

Also, you cant expect the check ball to not affect flow. Check ball fittings are restrictive otherwise they wouldnt work. How restrictive is debatable.

And I have never seen an OEM compression fuel fitting... To the best of my knowledge OEM doesnt support compression fittings on fuel or brake lines. If you're seeing any compression fuel line fitting at the parts store it doesnt mean its OEM approved. And I wouldnt use any nitrous kits as an example of whats legal since running nitrous isnt legal anyways... But nonetheless, nitrous runs through a solenoid which dumps into the intake and nitrous tanks have their own relief.

 

[JR]

I can't speak for jalex but I plumbed my spare because I got burned one too many times on the side of the road. On a bright sunny day, it's not too bad swapping pumps out. But I don't want to lay under a truck in the rain, snow, slop, or darkness, which I've done. Or on the side of a busy interstate. I suppose this isn't a big deal for those that never leave town and don't tow.
Good luck finding a consistent reliable lift pump for a gen 2. All the electric pumps have their down falls particularly the pumps that rely on a seal to sepersep motor from pump . Mechanical belt driven pumps have their own issues as well with priming and general reliability. Again pull vs push. Not the most efficient spot for a pump.
You keep mentioning a check ball, again I used ball valves. Not anymore restrictive than the ID of the pipe. And they don't fail.
Nothing wrong with JIC fittings I used them on my Air Dog. Jalex asked how to adapt from the OEM steel line. Haven't seen a JIC that will do that. There are a lot of ways to accomplish what he wants to do, I simply shared my experiences with tube fittings. You seem to be missing the point on the Nitrous reference. The point is they just don't leak like you say they do. Otherwise they wouldn't be so popular in use with a gas like NOS.

 

[KATOOM]

People been using FASS and Airdog Fuel Boss pumps for a looong time without issues.
Disclaimer: Airdog was sold about 7 years ago and lost quality so jalex I'd confirm with other members before using their pumps. But FASS has always been quality and Fuel Boss is a top notch system. The ONLY thing people ever run into with Fuel Boss is a potential drive belt break, but that takes seconds to replace. And prime loss is ONLY a problem if there's a leak.

Point being is anyone who chooses to use the factory Carter is just uninformed as those pumps had numerous reasons why they failed. I'm happy to list the reasons if you care.

I wont debate the check ball valve either...but physics are physics and cant be argued with. If you think I'm wrong then install a checkball fitting on your shower and see how works for you.

And if you want to install a JIC on a bare metal line then you'll need to flare it. Just note that its a 37* flare. NOT the hardware store fitting 45* angle.

 

[JR]

. If you think I'm wrong then install a checkball fitting on your shower and see how works for you

How about the ball valves that are used to isolate your shower head, Do they impede flow? Or the ones on your HW heater, or the ones that isolate your home water pump?' There are ball valves all over the average home....ball valves do not restrict flow. I used ball valves on my truck . No check valves . Ball valves.

I'll never own another Air Dog. I bought an AD100 about 10 years ago and it was nothing but headaches . Their warranty don't do you any good l when they require your junk pump for inspection before they will send you a new one. I ended up sourcing all the bearings, seals, and motor brushes through my local parts house and rebuilt it myself when the warranty expired. I'll never recommend them to anyone .

 

[KATOOM]

My mistake... I was misunderstanding you supporting jalex initial post about using a check valve in his fuel system. Yes, a ball valve would allow full flow. Still not what I'd advise on a fuel system but nonetheless, you're correct about flow.

And yes, AD did go through their moment of headaches. As I mentioned before, they were bought out. Cant remember exactly when that happened but it did cause quite a few people to be frustrated with their lack of customer service. Again, FASS and Glacier (Fuel Boss) are top notch companies.

 

[BoeingDiesel]

How about the ball valves that are used to isolate your shower head, Do they impede flow? Or the ones on your HW heater, or the ones that isolate your home water pump?' There are ball valves all over the average home....ball valves do not restrict flow. I used ball valves on my truck . No check valves . Ball valves.

I'll never own another Air Dog. I bought an AD100 about 10 years ago and it was nothing but headaches . Their warranty don't do you any good l when they require your junk pump for inspection before they will send you a new one. I ended up sourcing all the bearings, seals, and motor brushes through my local parts house and rebuilt it myself when the warranty expired. I'll never recommend them to anyone .

My AirDog lasted for many years but died about six months back so I installed a FASS and happy with it...guess I should change my truck Sig'.

JR, you don't have check valves on your HW tank do you? A check valve on the supply side of a re-circ' system is SOP.

 

[JR]

My AirDog lasted for many years but died about six months back so I installed a FASS and happy with it...guess I should change my truck Sig'.

JR, you don't have check valves on your HW tank do you? A check valve on the supply side of a re-circ' system is SOP.

I do not, but I have noticed them installed, along with an expansion tank, in certain family/friends units. I believe it is more of a city/municipality thing than a requirement for the equipment itself.

 

[ROBERT S HAUN]

Glad i bought an extra air dog elec. motor to carry as a spare, didn't know they went out of business.. The pump motor bolts on with 4-5 allen head bolts,easy to replace..

 

[Joe Mc]

Here's a twist for all. I've been running the Glacier Diesel Perf., GFS-392 big line system for almost 17 years without issue. Back when I bought the system they used a Walbro pump, don't see it on their site anymore tho. The Walbro is tiny, about 4" long and 2" diameter has served my truck (note info in signature) very well providing 22 psi (adjustable mechanical regulator set to my desired psi) for many, many years. I have a spare pump just in case, which can be changed with a 5/16" socket (or flat tip screwdriver) for the two hose clamps & wire connections to the pump and a ⅜" socket for the pump to frame mounting strap/loops. just saying, there are many options and different systems and parts available to do whatever you want. My $0.02