What it does
This table adds extra RPM on top of your normal target RPM as soon as the engine starts. The extra is timed, fading out until it adds nothing, so the engine settles back to its regular idle target on its own. It can be mapped in up to 3D, and coolant temperature is an obvious axis, since a cold engine usually needs more help.
It changes the idle target. Its partner, post start base offset, changes the idle valve or throttle position. They usually work together: one tells idle control to aim higher, and the other gives it the extra air to get there.
When you need it and what to check
- The engine starts, then dips or stalls within a few seconds: add a little offset and make sure the base offset supplies enough air to reach it.
- Idle flares high and hangs after starting: reduce the offset or shorten how long it lasts.
- Check fuel too. A lean or rich post start fuel correction often looks like an idle problem.
Need this diagram? Ask us and we'll send it over with advice for your build.
