Fuel-System Maintenance is Essential in Modern Engines

Without regular cleaning, today’s engines will not deliver the power and fuel economy they are designed to deliver.

Bottle of AMSOIL P.i. gasoline additive is poured into a vehicle.

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AMSOIL P.i. Performance Improver Gasoline AdditiveAMSOIL P.i.® Performance Improver Gasoline Additive
Alex Thompson
by Alex Thompson
November 29, 2024

It used to be common practice for vehicle owners to spend a Saturday afternoon in the garage, giving their vehicles a tune-up. There was a sense of pride and accomplishment in working under the hood, getting their hands dirty and knowing the efforts would help keep the car or truck running strong. Back then, vehicles were much easier to work on – the engine layouts were open, components were accessible and the average Joe didn’t need advanced training or complicated tools to perform maintenance.

AMSOIL Tech Tips on Motorhead Garage with host John Gardner and AMSOIL product expert Len Groom: Fuel Injection Explained
Video transcript: Fuel Injection Explained

Featuring John Gardner, ASE Master Certified technician, automotive technology instructor and host of Motorhead Garage, with AMSOIL Director of Product Marketing Len Groom (author profile).

John Gardner: Every year, automobiles are gaining horsepower, and they’re also getting good emissions, nice low emissions. Well, in the past, that wasn’t the case. You either had horsepower and bad emissions or good emissions and not a lot of horsepower. So what’s the deal?

Today, we’re getting them both. Well, that’s because of fuel injection, and that’s what this AMSOIL Tech Tip’s all about. Fuel injection. Where do we start?

Well, the evolution of course. Let’s take a look at fuel injection. Well, it evolved from carburetion. Carburetion was on your old cars.

No fuel injection whatsoever. We just dumped the fuel down there and that’s what you got, but it was nice wet rich mixture. That’s important. Then we went to TBI which was fuel injection.

It’s throttle body injection. Actually went down over the actual throttle body, washed the valves. Once again, a nice rich mixture. Then we went up to the multi port injection.

You can see the injector right above the valve. Got a little bit leaner. We got better fuel control, but we were still washing the valve. Well, today folks, we’re down to direct injection.

And Len, that’s important because with direct injection comes some inherent problems. Things like super lean mixtures, high pressures in the cylinder creating a lot of heat. That’s a problem.

Len Groom: Heat is a problem and that’s what you’re fighting here because heat has a tendency to build deposits and that’s what we’re seeing. We’re seeing deposits on piston crowns, ring lands, injectors. We’re seeing spray patterns being affected. So that’s why we’re recommending an additive in the form of our upper cylinder lubricant. It’s got a real potent detergency in it designed to take those high heat situations that we’re putting the fuel into, and we are recommending that every single tank. You wanna do it often.

John Gardner: And that’s important. I mean, putting it in the tank. These fuel systems, they can be dangerous. I mean, we’re talking about high pressure, and you really don’t wanna go in there and start busting open these lines with all the emissions of things that are going on. It’s hard to get it into the fuel injection system. So the tank’s the best way to go?

Len Groom: It is. Right. You want it the easiest way to bring it in there is is through the fuel tank, through the injector itself.

And you want

John Gardner: it every time you run it.

Is that the best way to do it, especially with the heat and the problem?

Len Groom: This will be considered an every tank fuel additive. Yes, sir.

John Gardner: Well, there you go. I’m gonna add it to my car, so you can too. Just check them out on the website at AMSOIL.com

A black Mustang cruises a country road in the fall.

Today’s vehicles are a different breed. The push for better fuel economy has led to smaller engines littered with computerized monitoring systems and complex technologies all tightly packaged together. As a result, most of us are taking our vehicles to repair shops for even the most routine maintenance. Yet all vehicle owners can still perform a quick engine “tune-up” with no tools or automotive background required. Instead of turning wrenches, it comes in the form of a fuel additive.

Corvette LT4 injectors.

What Detergents Do

Motor oils are tasked with several functions beyond just lubricating, including keeping engine components clean. This is made possible by the use of detergent and dispersant additives. Their role is to prevent contaminants from sticking to engine components, especially hot components such as pistons and rings. However, motor oil is not able to prevent deposit build-up on certain components, including fuel injectors, intake valves and combustion chambers. That’s where boosting the cleaning power of gasoline comes into play.

Shelf of AMSOIL products including AMSOIL P.i. gasoline additive.

Fuel injectors are traditionally located in the air intake ports, and they spray fuel in a fine mist that mixes with air as it passes by the backs of the intake valves. Fuel injectors of this style are appropriately called port fuel injectors. Port fuel injectors become clogged with deposits over time, which causes that fine mist of fuel to turn into an unpredictable stream of fuel. As a result, the fuel doesn’t mix as well with the air, and the combustion of the mixture is less effective.

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The Direct-Injection Problem

Now consider a gasoline direct-inject engine such as the Ford* EcoBoost* or GM* Ecotec,* which have fuel injectors positioned with the tip located inside the combustion chamber. Because of this location advantage, they can better control the spray of finely atomized fuel into the cylinders, leading to increased power, reduced emissions and most importantly these days, improved fuel economy. During normal engine operation these injectors are exposed to much higher temperatures and pressures, which leads to more rapid deposit build-up than the build-up on traditional port fuel injectors. The outcome of plugged injectors is the same – poor spray patterns causing lost power and efficiency.

A pickup truck pulls an UTV down a rural road.

In a port fuel-injected engine, the next components that can be reached through the fuel system are the intake valves. Their job is to allow air into the combustion chamber at the precise time that it is needed, then close tightly to seal the chamber during combustion. The valves tend to accumulate deposits over time that can prevent them from sealing properly, allowing pressure loss and poor engine performance. Since the port fuel injectors are positioned to spray at the valves, any deposits that form on them can be easily addressed through fuel additives. However, in direct-inject engines the intake valves never get fuel sprayed on them, so fuel additives have a minimal effect on cleaning those deposits.

Inside the Combustion Chamber

The final components that see a significant benefit from fuel additives are the components that form the combustion chamber itself: the piston, cylinder walls and head. The extreme temperatures and pressures they are routinely exposed to make them prone to deposit formation. These deposits can lead to hot spots that cause the air-fuel mixture to ignite before it should, resulting in uncontrolled combustion known as engine knock. Today’s engines have sensors to detect that condition, and they constantly make adjustments to compensate. The good news is that those adjustments prevent the knock from causing significant engine damage. The bad news is that the engine is no longer operating at its most efficient settings, leading to lost power and fuel economy.

AMSOIL P.i. restores up to 14% of horsepower with just one treatment.

Where P.i. Comes In

This is where quality fuel additives make a difference. Their role is to clean the deposits that the motor oil cannot reach. AMSOIL P.i.® Performance Improver is a highly concentrated formulation specifically designed to clean all of the deposits previously mentioned. In fact, P.i. cleans your entire fuel system and restores up to 14% horsepower1 in one tank of gasoline. The result is restoring and maintaining engine performance. No wrench-turning required.

1Based on third-party testing in a 2016 Chevrolet* Silverado* 1500, 5.3L V-8 GDI with 100,616 miles, using one tank treated with AMSOIL P.i. Actual results may vary.

This article is part of our Fuel and Fuel Additives guide. See every article in the guide.

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by Alex Thompson

Alex Thompson is Director of Product Marketing at AMSOIL. He guides product strategy, technical positioning and market development for automotive and commercial lubricants. Thompson works with product-development and communications teams to connect product capabilities with customer and equipment requirements. His AMSOIL Magazine Tech Talk contributions address oil consumption, hydraulic-system operation and the role lubricants play in component protection and system performance.

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