Glossary / General

fuel trims

13 Episode Mentions

Too Afraid to Ask

The car’s computer keeps a running tally of how much extra or less fuel it needs, and these numbers show that adjustment over time (long‑term) or in the moment (short‑term).

Technical Definition

Fuel trims are adjustments the ECU makes to the fuel injection map based on sensor feedback, with long‑term trims reflecting cumulative changes and short‑term trims reacting to immediate conditions.

Hear It Discussed

"it does have a displacement value that needs to be set and also your fuel trims need to be set and that curve goes by the displacement of the engine"
Talking About Car Repair on this Live Call In Car Talk Show Under The Hood show 48:19

"[49.8s] You know, I want to go back and talk real quick before I go to George and Alabama about fuel trim's or fuel economy once again... [73.8s] We assume if there's no check engine light on the..."
Ron Ananian, The Car Doctor - May 9, 2026 - Hour 2 - The Problems Your Car Isn’t Warning You About Ron Ananian The Car Doctor 00:49

"The fuel trims, both short term and long term closed loop trims [3927.5s] varying quite significantly."
161: Standalone vs OEM ECU: Understanding Modern Engine Control Tuned In 05:22