K20A2 Alternator wiring help

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Joined: Wed Apr 21, 2010 12:20 pm

K20A2 Alternator wiring help

Post by M111 »


I have fitted a K20a2 UK spec engine in my Lotus elise & looking to fit a smaller light weight alternator, there is very little electrics on this car so no need for the heavy oe one.

Im looking for a bit of info on what a couple of the pins on the 4 pin alternator plug are used for & more importantly what effect would they have on the ecu if they were no longer connected if i used a standard 3 wire alternator.

The pins on the alternator are,

L, Pretty sure this is just for the light (switch to ground?)
IG, live from the ignition switch
FR, Feild report, is the ecu using this to detect alternator load?
C, Linked to the ecu, is this used by the ecu to control the alternator output?

The other alternitive to fitting a normal 3 wire alternator would to try & find another 5 wire type from a smaller engined Honda, im looking for something like a 45-50 amp output, anyone know of a compatable alternator?