Before electronic fuel injection became the standard fuel delivery system, most cars had mechanical fuel pumps – because electric fuel pumps weren’t necessary. They weren’t necessary because mechanical fuel pumps can deliver the single digit fuel pressure that’s enough to feed a mechanical fuel delivery system; i.e., a carburetor.

A mechanical fuel pump is basically a housing inside of which is a diaphragm that creates suction via the up-and-down action of a lever that is operated mechanically, by the running engine. The pump is (typically) bolted to the side of the engine. There are (usually) two lines that screw into the pump; one draws fuel from the gas tank. The other sends the gas to the carburetor, which feeds the fuel to the engine. This comprises the entirety of the fuel delivery system in a carbureted vehicle.

The pump is generally held in place by two bolts. Undo those – and the fuel lines – and that’s all there is to removing the pump. Reinstalling it is the reverse. It’s only slightly more challenging than removing the wingnut that used to hold the air cleaner lid down (today, there are typically a number of cumbersome clips that have to be snapped open to get the lid off the box).  Almost anyone who has two working arms can replace a carbureted engine’s fuel pump is the point. And almost anyone can afford to buy the pump, too.

Even today – even given inflation – I can buy a new replacement fuel pump for a carbureted GM vehicle like my ’76 Trans-Am for about $40.

Marvel at what we’ve lost. What was only yesterday inexpensive and simple (and still is today, if you’re lucky enough to own a car with a mechanical fuel delivery system) has become precisely the opposite. To be fair, electric fuel pumps are also simple, but they can be shockingly expensive to install because they are not simple to install because (generally) you’ve got to get them out of the gas tank first. That’s where the majority of modern, fuel-injected cars have their fuel pumps. They are in the tank because the gas serves as a coolant, which is good (for the pump) and for you, because it extends the service life of the pump. Electric fuel pumps generally last longer than mechanical fuel pumps, which – back in the day – commonly needed to be replaced by the time the vehicle had 100,000 miles on the clock and sometimes, sooner.

But – remember – it was easy and inexpensive to replace those old mechanical fuel pumps. What’s $40 or so bucks (and 15 minutes of wrenching) once every five years?

The in-tank pump isn’t easy or inexpensive to replace.

Unless you’re very motivated and physically capable and have more than just a basic socket set and some wrenches, this is a job you’ll probably end up turning over to a dealer. The average cost ranges between $800 and $1,500. Also, you  probably will not be able to replace the electric pump in a parking lot. When it fails, you’ll likely have to call for a truck – and a tow. Because dropping a gas tank in the parking lot of a Wal Mart is an unlikely proposition. On the other hand, it was – and still is – easy to change out a bad fuel pump in a parking lot. No need to drop the tank – which requires a jack (gas is heavy). Just a basic socket set and wrenches is all you need.

And while we’re on the subject of fuel pumps, consider that the rest of the fuel system – in a carbureted car – can be replaced in about 15 minutes, too. Because that’s about all the time it takes to remove the four bolts that hold a carb to an intake manifold. That plus a few hoses and brackets is all there is to it. Even today, by the way, a brand-new four barrel carburetor costs about $500 – or about a third what it costs to pay a dealer to replace a fuel-injected cars’s electric fuel pump. The kicker? Once you’ve replaced the carb – and the mechanical pump – you basically have a brand new fuel system. The whole thing, in other words – less the lines and tank, of course.

It is true a modern, fuel injected system is “set and forget.” Once installed, it generally requires zero maintenance for a long time. Just turn the key and off you go. But – one day – you won’t go. And on that day, you may wish you only had to deal with a $40 mechanical fuel pump or – worst case – a $500 carb.

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