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DFS780 Fuel System - Full-time Operation

GM Diesel Trucks 11-16 V8-6.6L (td)
Part Number: 42-14021

MSRP: $1,126.22


  • Clear high-impact polycarbonate sight glass for visual inspection of fuel
  • Helical spur gears runs quieter than straight cut gears
  • "Marine Grade" motor protects against dust and water
  • 187 GPH @ 8-10 psi Flow Rating
  • Contoured CNC manifold enhances flow
  • Fuel pressure gauge port
  • O.E. quality Viton Seals
  • Typical install is 2 hours
  • Built in the U.S.A.
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Dads & Grads

Clear High-Impact Polycarbonate Sight Glass:
Allows visual inspection of fuel.

Helical Bronze Spur Gears:
Bronze gears more forgiving of contaminants than steel gears. The helical spur gear design runs quieter than straight cut gears.

Billet 6061-T6 Aluminum Manifold:
Eliminates porosity concerns with cast aluminum.

"Marine Grade" Motor:
Protected against dust intrusion and powerful water jets.

Plug & Play Installation:
Supplied harness attaches directly to battery and utilizes Deutsch weather-proof connectors. No cutting or modifications of the stock fuel lines required.  Vehicle can easily be returned to stock.

PEEK Bearing Wear Surfaces:
The DFS780 spur gears ride on PEEK (Polyether Ether Ketone) bearing surfaces to reduce both noise and wear.

Contoured CNC Machining Of Manifold Passages:
Enhances flow through the manifold to reduce pressure drop due to flow restrictions.

Direct Bolt-on Steel Mounting Bracket:
Heavy duty bracket mounts to the frame and utilizes existing hole to secure.

Fuel Pressure Gauge Port:
1/8 NPT port allows customer to attach an external pressure gauge to monitor fuel pressure.

O.E Quality Viton Seals:
Compatible with diesel and biodiesel fuels.

Note: This system is not currently CARB exempt and is not available for sale in California or for use on any vehicle registered with the California Department of Motor Vehicle.


Vehicle Applications

Year Make Model SubModel Engine Fuel
2011-2016Chevrolet Silverado HD 2500HD/3500HD (LML) Duramax Turbo Diesel V8 6.6L Diesel
2011-2016GMC Sierra HD 2500HD/3500HD (LML) Duramax Turbo Diesel V8 6.6L Diesel
Reviews (1)

Customer Reviews (1)

Overall average

Average Ratings By Category:

  • Quality
  • Value
  • Easy Install

1 Item(s)

Beyond easy to install, I highly recommend it!
What peaked my interest in the AFE DFS780 pump was not its rated flow (which mine tested 2.3 gals a min @ 10psi) or its filtration efficiency (which AFE states “up to 1 micron” and the Donaldson filter I use is 99% at 4 microns) but what got my attention was it’s very detailed instructions and ease of installation. Compared to the popular brands (Air Dog, FASS, Kennedy) this pump, in my opinion, is the easiest to install. NOW, this is strictly MY OPINION, which is only based on comparing the installation instructions for these pumps online. I obviously, have not installed all these pumps before and YOUR OPINION may differ...

The install was a breeze. The installation instructions (which come on a USB drive, I printed them) are by far the most detailed, easy to follow instructions I’ve ever used. Each step was simple to follow and included color photos, there was absolutely nothing to guess or figure out. The installation requires no cutting of lines, no cutting of the fuel tank fill tube, no drilling into the frame, and no sump. The pump includes new fuel lines, cut to length, that utilize the factory quick connect fittings, and a mounting bracket that uses existing holes in the truck frame, located just in front of the fuel tank. The install took me no time and only required a socket set, crescent wrench, allen wrench, and wire stripper. The fuel return line for the pump is suppose to eliminate the 1/4 of a tank issue that some pumps have by tying into the factory return line.

I usually fill up my truck at 1/4 of a tank but I did want to test and make sure there would be no issues if I went lower, just in case I ever need to. I ran the truck to almost an 1/8 of a tank (used just over 30 of the 36 gals) with no issues at all. The pump never sucked air and the sight glass stayed filled with fuel.

I did the install on 11/2/18 and have had no issues to report. No leaks, no lack of flow, no problems at all. I installed a pressure gauge onto the lift pump that will not be monitored all the time (as it is under the truck) but that I did record while I drove around. While running a 50hp tow tune, the truck idles and cruses at approximately 10psi – 10.5psi. Moderate to heavy acceleration will typically drop it to 9psi. WOT from about 40-95mph resulted in 8psi. I did this same test with my stock power level tune, which resulted in the same pressures. I do not run a tune higher than a tow tune, nor do I plan to.

I also just towed for this first time since the pump install. It was not a very long haul, only 250mi, but my truck pulled my 40ft 5er (around 16,000lbs) just fine, as usual. There was not a noticeable change, but this was expected, as I have never had any problems with fuel delivery prior to the install. I did average 11.9MPG which was a littler higher than I expected because I had a slight head wind and was in the MS hills. Near 12MPG is typically the best I see towing and is not typical for when I am in the hills or with a head wind. I doubt (but could be wrong) if this had anything to do with the new lift pump.

The only complaint I have with the pump is how low it hangs. It is the lowest hanging object in the area it is mounted. Now, this can be remedied by not using the sight bowl that is on the bottom of the filter/water separator. It is optional and can be removed with just the small, black drain installed on the filter instead. I have opted to leave the bowl installed as I have a spare filter and black drain incase something were to ever damage the bowl. I will say, that from what I have seen, it is in a location where objects from the tires don’t seem to be thrown. I have been in quite a bit of mud at work (not very deep though) and drove in the rain of course and nothing seems to hit the pump or filter. It has stayed clean and mud free, not even collecting much road grime.

As far as noise goes, the pump is not obnoxious but its not silent. A slight hum can be heard at idle, but not loud enough to be distracting or irritating, and I do have very sensitive ears. While driving, however, you would never know it is there (that’s with a straight pipe 4” exhaust). Even just cruising in high gear, I have never noticed it, just at idle.
  • Quality
  • Value
  • Easy Install
Review by Justin E / Posted on 12/20/2018

MSRP: $1,126.22

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