UpVehicle
  • News
    • All
    • Body & Suspension
    • Electrical, Electronic and Control Systems
    • Internal Combustion Engine
    • News & Tech
    • Powertrain system
    • Repairs and Maintenance
    • Uncategorized
    • Vehicle Culture
    • Vehicle Encyclopedia

    Top 5 nguyên nhân phổ biến gây ra sự rung lắc động cơ ô tô

    Troubleshooting Guide for Engine Can’t Start

    Troubleshooting Guide for Engine Can’t Start

    10 Reasons why Your Car Is Vibrating

    10 Reasons why Your Car Is Vibrating

    5 Signs to recognize the bad accelerator pedal position sensor

    5 Signs to recognize the bad accelerator pedal position sensor

    Kinetic Energy Recovery System (KERS)

    Kinetic Energy Recovery System (KERS)

    Terms: What is Fuel Trim?

    Terms: What is Fuel Trim?

    Trending Tags

  • Encyclopedia
    • All
    • Body & Suspension
    • Electrical, Electronic and Control Systems
    • Internal Combustion Engine
    • Powertrain system
    Kinetic Energy Recovery System (KERS)

    Kinetic Energy Recovery System (KERS)

    Terms: What is Fuel Trim?

    Terms: What is Fuel Trim?

    Terms/Acronyms for Automotive Engineering

    Terms/Acronyms for Automotive Engineering

    What is a gasoline particulate filter and how does it work?

    What is a gasoline particulate filter and how does it work?

    Adaptive cruise control – What is Adaptive Cruise Control?

    Adaptive cruise control – What is Adaptive Cruise Control?

    WHAT IS ANTI-ROLL BAR?

    WHAT IS ANTI-ROLL BAR?

    FIND OUT ROLL CENTER – WHAT IS THE ROLL CENTER?

    FIND OUT ROLL CENTER – WHAT IS THE ROLL CENTER?

  • Repairs & Maintenance
    Troubleshooting Guide for Engine Can’t Start

    Troubleshooting Guide for Engine Can’t Start

    10 Reasons why Your Car Is Vibrating

    10 Reasons why Your Car Is Vibrating

    5 Signs to recognize the bad accelerator pedal position sensor

    5 Signs to recognize the bad accelerator pedal position sensor

    Top 5 common causes of car engine vibration

    Top 5 common causes of car engine vibration

    Failure Symptoms of Crankshaft Position Sensor

    Failure Symptoms of Crankshaft Position Sensor

    Top 10 brake problems every driver needs to know

    Top 10 brake problems every driver needs to know

    Here are 5 simple ways to help extend the life of car battery

    Here are 5 simple ways to help extend the life of car battery

  • Login
No Result
View All Result
UpVehicle
  • News
    • All
    • Body & Suspension
    • Electrical, Electronic and Control Systems
    • Internal Combustion Engine
    • News & Tech
    • Powertrain system
    • Repairs and Maintenance
    • Uncategorized
    • Vehicle Culture
    • Vehicle Encyclopedia

    Top 5 nguyên nhân phổ biến gây ra sự rung lắc động cơ ô tô

    Troubleshooting Guide for Engine Can’t Start

    Troubleshooting Guide for Engine Can’t Start

    10 Reasons why Your Car Is Vibrating

    10 Reasons why Your Car Is Vibrating

    5 Signs to recognize the bad accelerator pedal position sensor

    5 Signs to recognize the bad accelerator pedal position sensor

    Kinetic Energy Recovery System (KERS)

    Kinetic Energy Recovery System (KERS)

    Terms: What is Fuel Trim?

    Terms: What is Fuel Trim?

    Trending Tags

  • Encyclopedia
    • All
    • Body & Suspension
    • Electrical, Electronic and Control Systems
    • Internal Combustion Engine
    • Powertrain system
    Kinetic Energy Recovery System (KERS)

    Kinetic Energy Recovery System (KERS)

    Terms: What is Fuel Trim?

    Terms: What is Fuel Trim?

    Terms/Acronyms for Automotive Engineering

    Terms/Acronyms for Automotive Engineering

    What is a gasoline particulate filter and how does it work?

    What is a gasoline particulate filter and how does it work?

    Adaptive cruise control – What is Adaptive Cruise Control?

    Adaptive cruise control – What is Adaptive Cruise Control?

    WHAT IS ANTI-ROLL BAR?

    WHAT IS ANTI-ROLL BAR?

    FIND OUT ROLL CENTER – WHAT IS THE ROLL CENTER?

    FIND OUT ROLL CENTER – WHAT IS THE ROLL CENTER?

  • Repairs & Maintenance
    Troubleshooting Guide for Engine Can’t Start

    Troubleshooting Guide for Engine Can’t Start

    10 Reasons why Your Car Is Vibrating

    10 Reasons why Your Car Is Vibrating

    5 Signs to recognize the bad accelerator pedal position sensor

    5 Signs to recognize the bad accelerator pedal position sensor

    Top 5 common causes of car engine vibration

    Top 5 common causes of car engine vibration

    Failure Symptoms of Crankshaft Position Sensor

    Failure Symptoms of Crankshaft Position Sensor

    Top 10 brake problems every driver needs to know

    Top 10 brake problems every driver needs to know

    Here are 5 simple ways to help extend the life of car battery

    Here are 5 simple ways to help extend the life of car battery

No Result
View All Result
UpVehicle
No Result
View All Result
Home Vehicle Encyclopedia Internal Combustion Engine

Terms: What is Fuel Trim?

Dr. Fields by Dr. Fields
April 28, 2022
in Internal Combustion Engine
1 0
0
Terms: What is Fuel Trim?
0
SHARES
26
VIEWS
Share on FacebookShare on Twitter

In modern cars with OBD-II systems, the front oxygen sensor measures the amount of oxygen in the exhaust gas and provides feedback to the engine computer ECM (or PCM), to see if the air-fuel mixture in the engine is poor (too much air and too little fuel) or rich (too much fuel and too little air).

The ECM (or PCM) adjusts the fuel supply accordingly to keep the air/fuel ratio at its optimum, which is 14.7/1 (14.7 parts air to 1 part fuel).

This process goes on continuously: When the oxygen sensor detects too much oxygen, the ECM (or PCM) will assume that the air/fuel mixture is thin and add more fuel. When there is too little oxygen in the exhaust gas (condensed air/fuel mixture), the ECM (or PCM) will reduce the amount of fuel. In technical language, this adjustment is called Fuel Trim, basically understood as fuel compensation.

Short term fuel trim (STFT)

When the front oxygen sensor is warmed up after a cold start, the engine computer ECM (or PCM) will begin to adjust the air/fuel ratio between thin and dense (poor and rich). This cycle happens about once or twice per second. This air/fuel ratio adjustment is called Short term fuel trim (STFT). Using a diagnostic scanner will show STFT as a percentage with “-” or “+” in Live Data mode. For example, if your car has a small vacuum leak, you’ll see the STFT increase to +10-15 % at idle and drop to +3-5% at higher speeds.

Long-term fuel trim (LTFT)

There is also a long-term fuel trim (LTFT), which is the long-term fuel trim of the base air/fuel ratio. For example, if over time the engine gradually develops a small vacuum leak, it causes the engine to run more lean (more air and less fuel). In the long run, the engine computer ECM (or PCM) compensates for this by adjusting the long-term fuel trim (LTFT) to inject more fuel. Long-term fuel trim is also displayed as a percentage with a “-” or “+” sign in a diagnostic scan tool. For example, a long-term fuel trim (LTFT) of +5% means that the ECM (or PCM) added some fuel, even though 5% is considered within the normal range.

Tags: EngineFuelTerms
Previous Post

Terms/Acronyms for Automotive Engineering

Next Post

Kinetic Energy Recovery System (KERS)

Related Posts

What is a gasoline particulate filter and how does it work?
Internal Combustion Engine

What is a gasoline particulate filter and how does it work?

May 4, 2022

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

  • Trending
  • Comments
  • Latest
5 SIGNS THAT THE FUEL PUMP Relay is failing

5 SIGNS THAT THE FUEL PUMP Relay is failing

April 25, 2022
Kinetic Energy Recovery System (KERS)

Kinetic Energy Recovery System (KERS)

May 4, 2022
5 Signs to recognize the bad accelerator pedal position sensor

5 Signs to recognize the bad accelerator pedal position sensor

May 3, 2022
Terms: What is Fuel Trim?

Terms: What is Fuel Trim?

April 28, 2022
5 SIGNS THAT THE FUEL PUMP Relay is failing

5 SIGNS THAT THE FUEL PUMP Relay is failing

0
FIND OUT ROLL CENTER – WHAT IS THE ROLL CENTER?

FIND OUT ROLL CENTER – WHAT IS THE ROLL CENTER?

0
WHAT IS ANTI-ROLL BAR?

WHAT IS ANTI-ROLL BAR?

0
Adaptive cruise control – What is Adaptive Cruise Control?

Adaptive cruise control – What is Adaptive Cruise Control?

0

Top 5 nguyên nhân phổ biến gây ra sự rung lắc động cơ ô tô

May 22, 2022
Troubleshooting Guide for Engine Can’t Start

Troubleshooting Guide for Engine Can’t Start

May 22, 2022
10 Reasons why Your Car Is Vibrating

10 Reasons why Your Car Is Vibrating

May 4, 2022
5 Signs to recognize the bad accelerator pedal position sensor

5 Signs to recognize the bad accelerator pedal position sensor

May 3, 2022

Recommended

Top 5 nguyên nhân phổ biến gây ra sự rung lắc động cơ ô tô

May 22, 2022
Troubleshooting Guide for Engine Can’t Start

Troubleshooting Guide for Engine Can’t Start

May 22, 2022
10 Reasons why Your Car Is Vibrating

10 Reasons why Your Car Is Vibrating

May 4, 2022
5 Signs to recognize the bad accelerator pedal position sensor

5 Signs to recognize the bad accelerator pedal position sensor

May 3, 2022

About Us

We bring you the best Premium WordPress Themes that perfect for news, magazine, personal blog, etc. Check our landing page for details.

Read more

Categories

  • Body & Suspension
  • Electrical, Electronic and Control Systems
  • Internal Combustion Engine
  • News & Tech
  • Powertrain system
  • Repairs and Maintenance
  • Uncategorized
  • Vehicle Culture
  • Vehicle Encyclopedia

Tags

Acronyms Adaptive cruise control Anti-roll bar Automotive Engineering Battery Body Brake system Causes Clean Diagnosis Energy Engine Exhaust treatment Fuel Guide High-tech How it work How to KERS Kinetic Energy Recovery System Maintenance Problems Reasons Roll center Self-driving car Start Suspension Symptoms Terms Troubleshooting Vibration
  • About
  • Advertise
  • Privacy & Policy
  • Contact

© 2022 JNews - Premium WordPress news & magazine theme by Jegtheme.

No Result
View All Result
  • News
  • Encyclopedia
  • Repairs & Maintenance

© 2022 JNews - Premium WordPress news & magazine theme by Jegtheme.

Welcome Back!

Login to your account below

Forgotten Password?

Retrieve your password

Please enter your username or email address to reset your password.

Log In