454 tbi won't idle when warmed up...

[Desert1957]

Small Block Chevy / Almost the same as a 454


ALDL connector under dash



How to calibrate the TBI IAC Motor

1-Engine warmed up, key OFF, tranny in PARK

2-Put a jumper wire from pin “A ” to pin “B” on the ALDL connector (should be the black wire & white wire) A metal paper clip works good for this.

3-Turn key to ON, do not start engine , wait 10 seconds. This
will extend the IAC pintle and close off the air passage in the
body of the TBI. Remove the electrical connection to the IAC
by pulling it straight out. Turn the key to OFF and remove the
jumper from the ALDL connector.

4-Start engine, and let it settle into idle speed. You may need to give it a little throttle to get it running. Connect the scanner to the ALDL and check the engine RPM. You want the engine RPM to be at least 125 rpm less
than what the “target idle speed” is set for in the chip. Use the throttle
screw to obtain the “125 rpm less” idle speed.

Example:Target idle speed in the chip is 700 RPM less -125 minimum idle speed = 575 RPM

5-Turn engine OFF. Connect the IAC connector.

6-Start engine and run for seconds, turn engine OFF and wait at least 30 seconds. This will reset the IAC control.

7-Start engine, in PARK, let it idle. Idle speed should be close to the “target idle” set in the chip, if the IAC is being controlled by the ECM.


Desert