According to common forum lore and as documented by http://e30world.com/transmission/BMW...nsmission-swap among others, there seems to be an embarassing amount of confusion as to how to get a 5 speed swapped car to behave.
After noticing that my 325-with-5-speed-and-M30 swap had inop cruise control, I decided to investigate a bit.
First of all I discovered that the CC conundrum indicated in the link is most easily solved by reading the EBA and location 6571-0 of the ETM: for manual cars, the connection at C143 is OPEN, with the CC harness end taped, unconnected, to the harness.
When one shorts pin 3 and pin 9 of C306 to bypass the AT switch that isn't there any more, the start harness end of C143 is hot at all times (from C301) and therefore will permanently inhibit CC operation (this function originarily inhibited CC operation in P and in N for obvious reasons).
There is, however, another thing to note. If one compares the AT to MT diagrams at 1240-0 of the ETM, one discovers that the whole start relay and wiring IS NOT THERE on MT cars, with Pin 10 on C200 (key crank signal) DIRECTLY CONNECTED to pin 18 on C101.
The CORRECT way to perform the auto to manual swap therefore is to remove the harness as per below and connect the BK/YL wire to C200 pin 10, which then goes to C101 pin 18, disconnect C301 (and connec it to the backup light switch as per 6322-0, getting the little harness togheter with the backup light switch), disconnect C143 and then follow the GN/BK wire that starts at pin 9 @C306, towards the Motronic ECU, and DISCONNECT pin 2 @ C131 [in my case, with the M30 swap, C131 was just left danging and C306 was not shorted as it should've been but hacked off - let's say that the PO and I have different styles). One can then remove the start relay, its bracket and it's harness, if desired, and have the car wired as it would have been had it been a manual from the factory. This removes an enormous number of potential start failures AND brings the car in line with what BMW intended. There is a further connection from C306 to G200 that can be removed as it's no longer of use and I am presently investigating what the other pin of C131 does. News in a bit.
After noticing that my 325-with-5-speed-and-M30 swap had inop cruise control, I decided to investigate a bit.
First of all I discovered that the CC conundrum indicated in the link is most easily solved by reading the EBA and location 6571-0 of the ETM: for manual cars, the connection at C143 is OPEN, with the CC harness end taped, unconnected, to the harness.
When one shorts pin 3 and pin 9 of C306 to bypass the AT switch that isn't there any more, the start harness end of C143 is hot at all times (from C301) and therefore will permanently inhibit CC operation (this function originarily inhibited CC operation in P and in N for obvious reasons).
There is, however, another thing to note. If one compares the AT to MT diagrams at 1240-0 of the ETM, one discovers that the whole start relay and wiring IS NOT THERE on MT cars, with Pin 10 on C200 (key crank signal) DIRECTLY CONNECTED to pin 18 on C101.
The CORRECT way to perform the auto to manual swap therefore is to remove the harness as per below and connect the BK/YL wire to C200 pin 10, which then goes to C101 pin 18, disconnect C301 (and connec it to the backup light switch as per 6322-0, getting the little harness togheter with the backup light switch), disconnect C143 and then follow the GN/BK wire that starts at pin 9 @C306, towards the Motronic ECU, and DISCONNECT pin 2 @ C131 [in my case, with the M30 swap, C131 was just left danging and C306 was not shorted as it should've been but hacked off - let's say that the PO and I have different styles). One can then remove the start relay, its bracket and it's harness, if desired, and have the car wired as it would have been had it been a manual from the factory. This removes an enormous number of potential start failures AND brings the car in line with what BMW intended. There is a further connection from C306 to G200 that can be removed as it's no longer of use and I am presently investigating what the other pin of C131 does. News in a bit.
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