Engine – Engine Idle Speed (IAA Unit) Set Up

You may find that your Figaro is idling too slow or fast. Engine idle setting should be set at around 850rpm.

WHAT THE IAA (IDLE, AIR, ADJUST) UNIT DO?
The unit which is mounted to the engine allows you to set up Idle, Electrical (headlights, indicators) and AC Loading. Looking at the unit, the first screw on the right is the Engines Idle Speed. The middle screw is for the Electrical Load (i.e. headlights) and the one on the left one is for AC Load Compensation.

Generally, you don’t need to tinker with the 2 compensation screws but here’s how to adjust everything.

1) Take the car for a spin and get it completely warmed up.
2) Set the parking brake and block the wheels so the car can’t creep. You may need someone to sit in the car whilst you do the adjustment.
3) Next put the car into Drive (or Reverse). Your choice but the car has to be in gear because the compensation circuits don’t operate in Park.
4) Adjust the idle speed. Aim for around 850rpm but the goal is to have the car idling smoothly – not shaking or rough. If the car is better a bit faster then so be it.
5) Next turn on the headlights. The compensation solenoid should kick in and the idle will momentarily change. Check the speed. The idle should be close or may be slightly higher than with no load. Adjust so that the car isn’t shaking or rough. TFS recommend screwing all the way in and then 5 x turns out.
6) Next turn on the AC. Adjust the third screw when the AC compressor cycles on. Check the speed and adjust so that the car isn’t shaking or rough.TFS recommend screwing all the way in and then 2.5 x turns out.
7) Turn off the headlights and AC and put the car back into Park. You’re done.