totalloser

Many ways to skin a cat, but I had hard start problems with high lift pump pressure and the factory lift pump setup is a bad joke. The lift pump is above the fuel tank and subject to vibration giving difficult dry primes at startup, and the relay that controls it is buried in the ecm. The OE style is overpriced about 240% for what it is.

So this is how I dealt with the whole mess. I bought two Carter P4070 pumps which are mechanically identical to the OE pump, but with post terminals and 1/4" npt ports. They come with really nice rubber isolated mounting bracket and 3/8" barbs along with a bunch of other random hardware.

http://www.summitracing.com/parts/crt-p4070 I got mine from NAPA though.

I mounted one on my frame rail after cutting the tank to engine steel pipe back, and ran 3/8" hose up to the stock pump location. Then I took the stock pump's fasteners and swapped them with the p4070 to make it bolt to the stock location. On the inlet I used the supplied hose barb, but on the outlet I got a 90 degree 1/4"npt to 5/16"nipple and aimed it vertically towards the fuel filter inlet nipple, and plumbed in the hoses.

I tapped power inside the underhood fuse box where there are two hot studs and ran inline fuses. One runs to a relay which is powered by the ecm signal for the OE pump to take the load off the ecm, and this power goes to the frame rail pump. The second one runs to the oil filter housing where I put a 1/8" npt "street elbow" to a 10psi normally open hobbs switch. The switched side feeds back to the second lift pump that sits in the OE location so that the second lift pump kicks on when the engine oil pressure comes up- this prevents hard starting from excessive pressure.

This setup addresses all of the issues known to me with the lift pump problems: No dry priming, no load on the ecm relay, no high pressure "hard starting", but plenty of flow and pressure (internally regulated to double pressure) to support mods WAAAAY beyond what I am running. Both pumps and all related hardware costs about the same as just a replacement stock style pump. Sorry for the terrible pictures, btw, I was too lazy to fetch a real camera.

Pic 1 is p4070 mounted to the frame. Pic 2 is the second pump ready to install in the factory block location. Pic 3 shows where the 1/8" npt plug can be removed to install the 45 and hobbs switch.

KATOOM

totalloser, awhile back (5+ years) it was very common to see people create a dual fuel pump set up. I think because there was limited info and experience with the new aftermarket fuel pumps like FASS, and because those pumps were not cheap either. I want to say I remember them being in the $700 range back then. With that said, some had success in their dual fuel pump arrangements but most eventually realized that it was a wasted effort. Why?.....well because the common choice of pump was the Carter lift pump and no matter how you set it up, that pump just has a high failure rate because of pump design. That went for many aftermarket fuel pumps because they seemingly weren't diesel compatible. Also, the problem people ran into was that when one pump fails, it goes unnoticed as the second pump must suck through the first pump or the second pump must push through the first one. Either way it was not good. So the dual pump concept went by the way side but there's still people out there who run them or continue to try them.

The only dual pump aftermarket system I know if is the Fuel Boss whereby it retains the OEM lift pump as a priming pump and as a possible back up pump. I think how I described it was right too.

Lary Ellis (Top)

I agree with ^^^

The problem is ending up with one pump trying to push or pull fuel through a bad one and because of the restriction you end up with little to no fuel.....just like a single pump going bad.

totalloser

The Carter lift pump is an excellent pump. I listed the causes that make it unreliable.

A LP failure in a dual rotary vane system will NOT block fuel flow.

This system works much better than stock, and has some advantages over $700 fuel systems- most notably, no "hard starting".

As to lift pump function, you hear it on the frame rail easily. It's not really loud, but it's loud enough. And testing the engine mount pump is simply a jumper wire across the Hobbs switch.

Dismissing this method outright is foolish. It works well- to a point. The real weakness is that the internally regulated which doubles the pressure, but still isn't very high. Not enough for major mods.

Just for context, I was running dual LP's a lot longer than 5 years ago. This just works better than having both on the same relay. I got sick of the hard starting from the higher lift pump pressure so rerouted the control circuit to the HOBBS and dumped my old factory LP. Which incidentally had been on for 100k and looked *perfect* with zero wear on the vanes.

Keep in mind, people still put stockers back on due to the cost of aftermarket systems. The *whole* setup I put on costs about the same as just a OE style replacement, and is FAR superior to the stock setup.

KATOOM

Dont misunderstand totalloser..... I'm not insinuating that what you're doing is wrong nor am I trying to educate you. If you've done this in the past then by all means do what works for you. No one says you have to run a FASS or Airdog or whatever. All I was doing was lending a hand based on the history I have on the subject. You're correct too that the Carter vane pump will not stop fuel flow as Carter changed the design in the mid 2000's whereas before that those pumps weren't a flow through design. That said, this doesn't change the fact that if one of the two inline pumps fails then the restriction will still be great and affect flow and pressure to the VP. If this is something you're comfortable with and you have monitoring gauges then I see nothing wrong with it. Given how sensitive the VP is to fuel flow, or lack thereof, I'm cautious of ANY fuel pump system failing while driving down the road.

high bid

Listening & watching this
I have run two LP for 4+ yrs but am constantly changing the one on the frame (annually). I'm now still running the replacement aftermarket pump from RockAuto in the factory LP location which outlasted the summit pump on the frame and wondering which direction to go from here. This pump is good 20psi at idle 14 under load.

drewk88

I run twin Edelbrock pumps.
With a check valve at the output of each pump, I can run either pump or both pumps from the cab with a dual power switch.
I can monitor the current of each motor in the cab, I found the motor current starts to drop off well before the pump fails.
Of course, I can also see the fuel pressure produced by either pump or with both of them running.
I have plenty of pressure at WOT with one pump, so It's like carrying a spare that I can change just by flipping a switch.

KATOOM

Well I certainly give you an "A" for effort. Thats quite a set up. Although I'd be a little concerned about the open electronics in wet/corrosion areas.

totalloser

The full failure of the dual LP system is highly unlikely, thus this is an advantage, not a detriment. If on pump fails, it will still have almost stock level of fueling rather than zero if an aftermarket high performance pump fails.

To understand why it is highly unlikely to have a blockage, it's useful to see the inside of a stock carter pump. The vanes (steel) sit in a steel rotor with a negative rake. To block flow, the rotor would have to seize AND the specific vane in the flow path would have to seize in the fully extended position. Very very unlikely situation. Most likely one of two things would prevent fuel blockage: The rotor would be pushed by fuel flow into a fully unobstructed position, or more likely the vane would simply push into the rotor. The vanes are not sprung.

To my knowledge, these pumps have always been this design, which is (IMO) king kong of methods of fuel movement. Some might argue that orbiting geroler or trochoid. I disagree since these latter designs when small electric motor driven will seize on particulate where a rotary vane will sacrifice one vane worth of flow and pass the particulate, which the fuel filter will then trap. Very resistant to seizure from particulate. I don't consider diaphragm even in the running alongside these designs.

If one fails with my system, it's $100 at the parts store, and probably *in stock*.

So to summarize: No hard starting, adequate fueling for basic bombed truck, cheap to build, more reliable, and very cheap and easy to maintain. Not for everyone, but works well for me.

I can't take credit for the Hobbs idea. I read about it years ago and immediately recognized the benefit, but only recently set it up. I wish I could cite credit to the "inventor", it was a good idea.