We’ve said it before, but it bears repeating: The benefits of electronic fuel injection over carburetors are many. EFI is pretty simple, with just a few moving parts, and these systems run well at any angle. The computer uses an oxygen sensor to constantly tune what the system is doing making power while running efficiently. EFI systems have proven to last for hundreds of thousands of miles with little to no maintenance in OEM vehicles. Shall we continue? Also, compared to EFI, carburetors are old. Parts for them are old, folks who know how to rebuild them are old, and the technology is old. As a result we often suggest upgrading to one EFI system or another to keep your trail rig running well. Sounds great, right? Not always.
Fuel-injection systems generally require higher fuel pressures in the range of 15 to 90 psi. Your old engine-driven fuel pump won’t provide anywhere near that, so the easiest way to get the pressure is to use an inline externally mounted fuel pump. And while that sounds great, one issue that almost always rears its ugly head after the swap to fuel injection is an external fuel pump failure. Here are the facts. Electric fuel pumps work hard. They don’t like getting hot, and heat leads to fuel cavitation, which makes the pump even hotter. Last but not least, off-roading in the heat usually gets just about everything hot, including externally mounted fuel pumps. Generally, almost all fuel injection systems built by OEMs use an in-tank fuel pump for their electronic fuel injection. They do this for a few reasons, but one simple one is that the fuel bath the fuel pump lives in lubricates and keeps the pump cool.
So you’ve probably surmised that you will want an in-tank fuel pump to run your EFI, but that’s not always easy since older 4x4s lack any provision for one. We had just this problem with our 1978 Ford F-250 4x4, which had recently been upgraded with a Summit Racing Equipment MAX-efi 500 self-tuning throttle-body fuel-injection system. One hot summer afternoon the external fuel pump began showing the telltale signs of external fuel pump death. We limped back home and called up our friends at Summit, who suggested one of Aeromotive’s Phantom Stealth Fuel Systems. This kit retrofits into fuel tanks of all kinds. It’s easy to install and includes just about everything you need to upgrade from your external fuel pump system.
We started the installation by opening the box of the Aeromotive Phantom 200 Stealth Fuel System (PN 18689, $487.98). Included are pretty much all the parts you will need minus a drill, a hole saw, and a few -6 AN fittings for the feed, return, and vent. We began by selecting the best spot for the internal retainer ring. You want to find a surface that is not too corrugated with ribs because this thing has to seal to keep fuel in and dirt and grime out.
We then predrilled a 1/4-inch hole to ensure that the 3 1/4-inch hole saw would cut in a safe and controlled manner. You also want to only perform this installation on either a new or very well cleaned tank. Trapped gasoline fumes can ignite and turn the tank into a bomb, which can severely injure or kill you. You also want to avoid a spot that would cause the new parts to interfere with the vehicle’s frame or tank supports when mounted, the fuel tank’s existing filler tubes, and the fuel level sending unit and its float inside the tank. The center of our tank was the best spot for ensuring a good seal.
The Aeromotive installation ring indexes in the hole and has pilot holes for the mounting holes that secure the pump hanger assembly. You want to make sure that the installation ring is rotated so the fittings on the pump will clear under the vehicle. Also check to make sure that none of the mounting holes you will have to drill will go through the side of any corrugations in the tank. Start by drilling two mounting holes 180 degrees apart through the installation ring using the supplied No. 2 drill bit. Then use the supplied screws and nuts to secure the ring in place before drilling the remaining 10 holes.
With the installation ring removed we cleaned up any burrs from the new cut edges with a deburring tool and used a magnet on a stick to clean up as much of the metal shavings as possible. We also then took a depth measurement on the tank to determine where we will set the pump, strainer, and foam baffle assembly. Since our tank is deeper than 12 inches we also had to use the Aeromotive Phantom Fuel Pump Extension kit (PN 18788, $179.19).
With our depth measurement known we used the supplied parts to set the fuel pump location. We secured the pump to the trimmed-down stainless steel hanger with the supplied band clamps. We then installed the fuel pickup tube and strainer, and wired the pump. We then test-fit the pump assembly.
With everything test-fitted we installed the retainer C-ring with studs and bolted the installation ring back on the tank. The ring helps funnel the trimmed foam and rubber baffle into the tank. This baffle will surround the pump and keep the pump submerged as the vehicle goes around corners, accelerates, and decelerates, preventing cavitation and fuel starvation.
With the baffle in place we test-fitted the pump assembly made adjustments and installed the pump into the tank with the supplied 1/2-inch-thick gasket. Aeromotive claims that the gasket, when properly installed, should seal even on 1/4-inch-deep corrugations and recommends a fuel resistant Dow Corning fluorosilicon RTV sealant for deeper or oddly shaped corrugations.
The fuel pump has -6 AN female O-ring ports on the body. We ordered up two male O-ring -6 to 3/8-inch barbed fittings for the fuel vent and fuel return fitting, and one -6 male O-ring to male -6 AN adapter. This allowed us to reuse the -6 fuel feed fittings we installed when we upgraded to the EFI system here: fourwheeler.com/how-to/engine/1710-an-easy-fuel-injection-option-for-your-engine/.