What is the range of long-term fuel trim values?

[Eileen]

Long-term fuel trim values range from negative 23% to positive 16%. Long-term fuel trim is a numerical parameter. Long-term fuel adjustments are derived from short-term fuel trim values and represent long-term fuel delivery corrections. Long-term adjustments account for normal aging issues such as component wear during operation. If the long-term fuel trim value exceeds 5%, it indicates a fault in the engine system; if it is significantly below 0% (a negative value), it indicates an overly rich mixture and fuel delivery should be reduced; if it is significantly above 0% (a positive value), it indicates a lean condition, and the PCM will increase fuel delivery to compensate.

[MacAlessandra]

I usually enjoy tinkering with cars. The long-term fuel trim value should generally stay within the range of -10% to +10% to be considered normal. If it's too low, say -20%, the engine might be reducing fuel, which can paradoxically increase fuel consumption. Conversely, if it's too high, like +15%, the engine could be adding excessive fuel, leading to higher consumption. If the value falls outside this range, there's an 80% chance of an air leak or a faulty sensor. I've encountered similar issues when helping a friend check his car—it was running rough, but replacing the oxygen sensor fixed the problem. In summary, just read it with an OBD tool. Don't underestimate this value; it's crucial for the health of the entire emissions system. Regular monitoring can help detect issues before any noticeable shaking occurs.

[AngelinaMarie]

When driving my SUV, I've been keeping an eye on the long-term fuel trim values, which are said to have a standard range of -10% to +10%. Last time, it jumped to +12%, resulting in noticeably higher fuel consumption. I had to refuel every few dozen kilometers, which made me rush to the repair shop for a check. It turned out the air filter was clogged, and after cleaning, the value returned to normal. Regularly monitoring this can help prevent minor issues because the engine is automatically adjusting the air-fuel mixture. Values outside the range mean either too much or too little fuel is being added, directly affecting the engine's smooth operation. I recommend plugging in an OBD reader after starting the car to check if the readings are stable.

[OwenLynn]

I've worked on many cars before, and the long-term fuel trim's reasonable range is -10% to +10%. Once my car's long-term value went to -15%, and it shook like it was falling apart at idle. After checking, I found the oxygen sensor was faulty. Replacing it immediately made it run much smoother. A value that's too far off indicates excessive compensation by the car, such as a vacuum leak or dirty fuel injectors. It's important to get it checked in time to avoid engine damage. Just read the numbers with an OBD tool to find out.