Understanding Fuel Trims %

Understanding Fuel Trims

The fuel trims are what govern what's going on inside the engine. This video is sponsored by Auto Value and Bumper to Bumper.

CC:

Let’s take a trip. It’s 1974. You’re in Denver, Colorado. You’re in your car that has a carburetor, and you’re getting ready to go over those rocky mountains to go to California. You’ve noticed that you’re halfway up the mountain, the engine’s starting to struggle. You go a little bit further. You notice that you start misfiring and the plugs are fouled. So what’s going on here? Well, essentially with this, you have the blue, which represents oxygen, and the red represents fuel, and this is the perfect ratio. But you’re taking away this oxygen, and when you take away the oxygen, you should take away the fuel. Carburetor can’t do that because it has fixed jets, and the metering stays constant no matter what altitude you’re at. This is why certain shops in Colorado specialized in carburetor tuning. Let’s fast forward 50 years, and you’re in a modern vehicle.

You’re in Denver, Colorado. Same situation with this. The fuel trims are what govern what’s going on inside the engine. So as that air density changes and the amount of oxygen entering the vehicle goes down, again, it’s able to then take the fuel and reduce that. So let’s say you make it to California, you’re on the west coast, and the air density is even higher. If you head to the carburetor vehicle and you had it tuned in Colorado, it might be a little at tuned, but with modern vehicles, they’re able to adjust the fuel trim and add a little fuel so the engine runs better and has lower emissions. So what is a fuel trim? There’s two kinds. Short term and long term. Short term is in the moment what’s going on right now in the engine, a long term that indicates overall health of the engine and how much it’s adjusting for the changes in oxygen levels. With this, it’s able to adjust to make sure that the engine’s running properly so you can make it over that mountain. I’m Andrew Markel. Thank you very much.

This video is sponsored by Auto Value and Bumper to Bumper.

You May Also Like

Schaeffler and Sustainability with Jerry Conroy

Conroy shares insights into his career trajectory, the evolving landscape of the company’s aftermarket operations, and its commitment to innovation and sustainability.

In this episode of AMN Drivetime, Bill Babcox is joined by Jerry Conroy, vice president USA and Canada, Automotive Aftermarket for Schaeffler. Conroy shared insights into his career trajectory, mentorship experiences, and the evolving landscape of aftermarket operations.

Conroy's journey into the aftermarket began during his college years. He stumbled upon an internship at Bendix, a commercial vehicle supplier based in Elyria, Ohio—his hometown. Little did he know that this opportunity would kickstart a career spanning 17 years at Bendix, and later transition into a leadership role at Schaeffler in the automotive aftermarket.

Flushing the Brake Fluid is Critical on Every Brake Repair

Making sure the brake fluid is the correct quality is critical. Sponsored by Auto Value and Bumper to Bumper.

Selecting the Right Oil for your Customers Engine

Learn how to educate customers on the importance of OEM specifications and premium lubrication for their vehicles’ maintenance needs.

At the Intersection of Tradition and Innovation with Grace Hovis

Grace Hovis’s journey in Hovis Auto & Truck Supply blends tradition with digital innovation in the automotive aftermarket industry.

Turbocharger Maintenance ft. Rein TechSelect Turbo Kits

Learn about common challenges with turbocharger maintenance and how Rein TechSelect Turbo Kitsmake the repair process easier for technicians.

Other Posts

The Standard® Advantage

Standard® knows that what comes out of a repair is directly dependent upon what goes into the box. This video is sponsored by Standard®.

Tesla Model 3 TPMS Service

Resetting and programming TPMS sensors for a Tesla is a lot like any other vehicle, and the challenge is still the same: keeping the light off.

Can You Jumpstart an EV?

First thing’s first: Find the LV battery, which could be anywhere in the vehicle.

Understanding What Antifreeze/Coolant Actually Does

Today, each manufacturer has its own formula for best results in their vehicles. This video is part of the Group Training Academy.