How to Ruin (and Fix) a Perfectly Good Fuel Pump in a G-body

How to Ruin (and Fix) a Perfectly Good Fuel Pump in a G-body

There are two things you need to know when it comes to the installation and care of your electronic fuel pump, regardless of what platform you choose: don’t trust an old tank of gas and always use secure wiring connections. Failure to heed either of these warnings can ruin a perfectly good fuel pump, which is exactly what happened in my 1983 Buick Regal.

G-bodies can be an acquired taste, and I have to admit this Regal has grown on me over the years. It was built into a Pro Touring machine with Detroit Speed suspension, Forgeline wheels, Antivenom/American Powertrain T-56 transmission, and 426-horse Chevrolet Performance LS3 E-Rod. To fuel the LS3, the low pressure factory fuel system was swapped for an ‘86-’87 style tank, bucket, and fuel pump with Russell fuel lines. Unfortunately, multiple moves from NJ to FL to CA left the Buick dormant for long stretches of time. Long story short, some fresh fuel was added to the tank, but there was several-years-old sludge clinging to the bottom of the tank. This was discovered when engine suddenly wouldn’t fire. It was then brought into the Power Automedia shop for diagnosis.

After taking delivery of the Buick, it was immediately apparent not all of the wiring was the most tidy or even safe. Before the Regal was even pulled into the shop, the most logical guess was that it suffered from a (hopefully) simple wiring issue. Once the tank was lowered, tech manager Dean Jigamian and shop tech Scott Nogrady immediately called my attention to the sludge. They also pointed out that the fuel pump wires had been simply twisted and were held together mostly by corrosion. Clearly the 10% ethanol content of the fuel wasn’t helping matters, but the shoddy wiring could have easily sparked a fire. Yikes!

Faulty wiring and old gas (with ethanol) in the tank spelled failure for this zero-mile aftermarket fuel pump.

Before this and other issues unfolded, we were in a scramble to get the Buick ready as we approached the midway point of the race season. Holley LS Fest West, Good Guys Del Mar, and the NMCA Autocross were right around the corner. Thankfully HyperFuel Systems in Riverside, CA is just a stone’s throw from our office, and came to the rescue with the Buick stranded on the lift. One call to our old friend Ken Farrell and he dropped off a 440 lph pump (PN 40017) from one of their all-in-one tank kits. He assured me the “Tight Fit” EFI fuel pump (PN 40106) would fit inside the factory Buick bucket and mate to the factory sending unit. This pump might seem like overkill for the current combination, but I had every intention of pushing it much further with boost. Plus, as it turns out, it is extremely dangerous to simply go by the advertised flow rate.

HyperFuel’s 440 lph Tight Fit EFI Fuel Pump (PN 40106) was the perfect fit for the ’86-’87 Grand National/T-type fuel tank on this Buick.

HyperFuel was kind enough to send us complete flow data on the 440 lph pump, which as it turns out will actually flow up to 612 lph depending on the fuel pressure. “A common misconception people have is that fuel pumps create pressure,” Kenny Farrell (Engineer at HyperFuel and Ken’s son) informed us. “Most people ask ‘what pressure does that pump operate at?’ But the real answer is that fuel pumps do not create pressure, they create flow. It is then up to the regulator to create a restriction to make the pump operate at the desired pressure.” This 440 lph pump supplied by HyperFuel is a high pressure capable pump, meaning you can run this pump at carbureted or EFI pressure with the use of the correct bypass regulator. Hyperfuel has a line of regulators that are modular and can switch between EFI and carbureted pressure by changing the internals with a swap kit (PN 44010, 44030).

If you are unfamiliar with flow charts for fuel pumps, this data may surprise you. However, creating this level of transparency allows you to properly spec your fuel system. For example, base fuel pressure for an LS engine (with EFI) is 58 psi – at which point the 440 lph pump is actually producing 323.66 lph and capable of supporting 1,026hp. However, if you planned to match boost pressure from a supercharger or turbo at a 1:1 ratio (as is common), the limits become more apparent – at 15psi of boost you’d only have 263lph of fuel flow, which is about 834 hp at the crank. This is exactly why HyperFuel has dual 340 lph fuel pump setups and other solutions to feed an increasingly demanding customer base.

Note: this test was conducted by an independent third-party at 13.5 volts and 100 degrees F. Horsepower values are calculated with Brake Specific Fuel Consumption at .50.


Since the HyperFuel pump fit into the factory ‘86-87 Grand National/T-type bucket as promised, the install was very straight forward. Scott dropped the tank, unscrewed the locking ring on the fuel pump module, and removed the assembly. The old, corroded pump was removed along with the sending unit and wiring. The gas tank was then flushed out to clean debris and old fuel from the tank. After prep was completed we placed the HyperFuel pump and a brand-new sending unit from a local parts store into the bucket.

Dean then soldered the fuel pump wires and put some heat-shrink over the connection. In addition to the in-tank wiring we also replaced the external wiring for the vehicle’s sending unit and fuel pump with a service connection weather pack, should we ever need to drop the tank down again. After the installation was complete, the Buick instantly came back to life. We’ll be addressing the rest of the wiring and a few other issues soon, in order to finally get this car on the road – and the track.

The HyperFuel 440LPH pump fit right into the ’86-’87 fuel bucket, however all of the wiring was replaced along with the sending unit. The previously installed parts were corroded and unusable.

We did reuse the sock, however, we may later replace this and look at heavier-duty methods of keeping the pickup submerged in the G-body.

After carefully maneuvering the fuel pump assembly into the tank, the locking ring secured it and the tank was ready to be re-installed.

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