e30 (late model) s5x OBD1 Swap A/C idle Bump Solved!
e30 (late model) s5x OBD1 Swap A/C idle Bump Solved!
Like many other obd1 swapped s5x cars, mine too has suffered from the unbearable issue when the you turn the AC on the DME doesn’t know to bump the idle and compensate for the additional load. Thus as you hit a red light your idle hops and surges between 500-900 rpm for a moment before leveling out.
As common as I’d assume this issue is I’ve had terrible luck finding any clear direction on how to resolve this. Particularly for OBD1 s5x swaps.
The OBD1 late e30 (88+) s5x solution:
Ultimately, when the AC button is clicked on we need to send a +12v signal to the DME at pin 64 (Compressor signal, Integrated Climate regulation control module). This needs to happen only when the switch is activated.
On late model cars there should be a loose pigtail for the hot A/C lead (a black 2 wire connector in/behind the center dash that is wrapped in gray factory tape). Look for it and use the blk/red wire (+12v when ac active) and run that to pin 64 on the DME (in my case violet/gray wire coming from the x6000). This will give the car the idle up when you energize the A/C. Without this the car will idle-cycle (up and down) because the DME will not know to raise the idle for a load. You can reach the pigtail by removing the dash side panel in the glovebox. Also pulled the glovebox pins out and dropped it, not removed it. More on this : http://www.r3vlimited.com/board/showthread.php?t=89460 and http://www.r3vlimited.com/board/show...=388079&page=2
For reference, my car is a 90 e30 m3, s52 swap converted obd1 (413 Red Label & harness out of a 95 525i).
For OBD1 early e30 (pre 88) s5x: Not sure here, maybe someone can chime in?
For OBD2 e30 s5x see: http://www.r3vlimited.com/board/show...=249136&page=4. You’ll need to follow “MC Hammered’s” example of creating your own relay which grounds pin 16 while at the same time supplying +12v to pin 19.
Check you manuals before surgery!
Like many other obd1 swapped s5x cars, mine too has suffered from the unbearable issue when the you turn the AC on the DME doesn’t know to bump the idle and compensate for the additional load. Thus as you hit a red light your idle hops and surges between 500-900 rpm for a moment before leveling out.
As common as I’d assume this issue is I’ve had terrible luck finding any clear direction on how to resolve this. Particularly for OBD1 s5x swaps.
The OBD1 late e30 (88+) s5x solution:
Ultimately, when the AC button is clicked on we need to send a +12v signal to the DME at pin 64 (Compressor signal, Integrated Climate regulation control module). This needs to happen only when the switch is activated.
On late model cars there should be a loose pigtail for the hot A/C lead (a black 2 wire connector in/behind the center dash that is wrapped in gray factory tape). Look for it and use the blk/red wire (+12v when ac active) and run that to pin 64 on the DME (in my case violet/gray wire coming from the x6000). This will give the car the idle up when you energize the A/C. Without this the car will idle-cycle (up and down) because the DME will not know to raise the idle for a load. You can reach the pigtail by removing the dash side panel in the glovebox. Also pulled the glovebox pins out and dropped it, not removed it. More on this : http://www.r3vlimited.com/board/showthread.php?t=89460 and http://www.r3vlimited.com/board/show...=388079&page=2
For reference, my car is a 90 e30 m3, s52 swap converted obd1 (413 Red Label & harness out of a 95 525i).
For OBD1 early e30 (pre 88) s5x: Not sure here, maybe someone can chime in?
For OBD2 e30 s5x see: http://www.r3vlimited.com/board/show...=249136&page=4. You’ll need to follow “MC Hammered’s” example of creating your own relay which grounds pin 16 while at the same time supplying +12v to pin 19.
Check you manuals before surgery!
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