EACV, IACV, RACV

Electronic air control valve 2-wire and 3-wire connectors

EACV systems control the amount of air still coming into the engine when idling. Without them the engine would stall when you lift your foot from the throttle. When applying throttle and at higher rpms the EACV is closed. At cold engine temperatures the EACv controls the temporarily higher engine rpm at idle.

There are two very common systems of valves used, a so called 2-wire or a 3-wire system with either 1 or 2 signal wires. The latter is sometimes also called an RACV since the mechanism inside is a rotary type. ECU’s can either control one or the other. So often with engine swaps a 2 to 3 or reversed swap is needed. Here are the connector pinouts which I generally encounter to help you out:

IACV / EACV 2-wire pinout.

Nomenclature:
IACV – signal wire
IGP – 12V battery feed

RACV / IACV / EACV 3-wire pinout

Nomenclature:
IACV N – signal wire Negative side
IACV P – signal wire Plus side
IGP – 12V battery feed

When swapping to one or another I typically use IACV P for IACV and vice versa. IGP stays IGP naturally. So IACV N is either discarded or newly added. Most commercial ECU conversion harnasses I have come accross use the same logic, often IACV and IACV P are shorted with each other to accomodate 2-wire and 3-wire systems without altering any wires in the conversion harnass itself.

Dodo Bizar

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