Wiring help on C104/C101 (early engine, late car)
Hey all, I'm in need of a second set of eyes on the wiring I'm doing for my S14. The motor came out of my '88 Henna M3 which had a 5/87 build date, so it's technically a 1987 M3. The engine harness has the C104 plug near the ECU.
The receiving car is a 1989 without a corresponding C104 plug on the chassis harness. Most of my searching has come up with wiring for people swapping later motors into earlier cars - I'm doing the opposite.
Here's what I have come up with:
A) For the tach signal, I can run a wire from the C104 into the engine bay and integrate it into the engine side of C101. It looks Pin 9 of C101 on the chassis harness expects the tach signal. There is no Pin 9 on the engine harness, so I need to add that and connect it to the tach output from C104 (pin 1, black)
B) For fuel rate, I need to run a wire from Pin 3 of C104 (white) back into the engine bay and integrate it with the engine side C101 plug. Looks like it is Pin 8 of C101 - the S14 harness has no pin there either, so I need to add one there as well.
C) I have no idea what to do about Pin 2 of C104 (green wire). For the "e to i" swaps, I have read that the chassis C104 needs this pin to be connected to the coil. But what about in my case, with the engine harness C104? I can't find reference to this pin in the 1987 M3 ETM. Supposedly it's a fuel cut from the OBC?
If anyone could 1) verify what I'm going to do seems correct and 2) clear up the Pin 2 business, that would be great. Thanks in advance!
The receiving car is a 1989 without a corresponding C104 plug on the chassis harness. Most of my searching has come up with wiring for people swapping later motors into earlier cars - I'm doing the opposite.
Here's what I have come up with:
A) For the tach signal, I can run a wire from the C104 into the engine bay and integrate it into the engine side of C101. It looks Pin 9 of C101 on the chassis harness expects the tach signal. There is no Pin 9 on the engine harness, so I need to add that and connect it to the tach output from C104 (pin 1, black)
B) For fuel rate, I need to run a wire from Pin 3 of C104 (white) back into the engine bay and integrate it with the engine side C101 plug. Looks like it is Pin 8 of C101 - the S14 harness has no pin there either, so I need to add one there as well.
C) I have no idea what to do about Pin 2 of C104 (green wire). For the "e to i" swaps, I have read that the chassis C104 needs this pin to be connected to the coil. But what about in my case, with the engine harness C104? I can't find reference to this pin in the 1987 M3 ETM. Supposedly it's a fuel cut from the OBC?
If anyone could 1) verify what I'm going to do seems correct and 2) clear up the Pin 2 business, that would be great. Thanks in advance!