Cheat from MembersPage/MarcellGal/EngineSwap/AirFeed (idle air section)
instead of the usual 1-2, 3-4 (iac_step_seq=0xC9 or 0xD8) the stepper windings are connected as 1-4, 2-3 (64 Ohm each)
I concluded that 0-3 and 1-2 must be driven a half period away from each other. So we need either
- 0 1 3 2 (0x1E)or
- 0 2 3 1 (0x2D)
History and LESSON
Unfortunately installer forgot to document this (it would have taken 2 mins when he made the install (when car-back was off), while it took half day to investigate with the car-back on. The car owner apparently doesn't have proper drawings or connect-lists of his engines's, VEMS installers should make sure to leave this info at the owner.
- we searched for a similar connector to connect to IAC
- made a test-fixture (connector with cable) to connect to iac
- that can be controlled from a spare-VEMS controller (this turned out to be unnecessary, but it was made the same time with the fixture to avoid a short drive back-n-forth)
- swapped to the test-fixture and found how it is in fact connected
- controlled from the spare VEMS