I thought this information might be useful to those swapping engines which have a 5 wire MAF with the integrated air temperature sensor and for those with 24v engines looking for additional intake options.
I bought a cold air intake for the E46 M3 and I discovered the 4 wire round plug MAF for the E36 is too large to fit in the hole and is oriented 90 degrees. Instead of trying to modify the aluminum intake I looked into rewiring my S50 harness for the 5 wire MAF.
I found this posting on this 7 series forum on how to wire the MAF:
From the wiring diagrams I came up with the following:
S50b32 Mass Air Flow Sensor
#1 pin on MAF (BR/OR wire) to Ground
#2 pin on MAF (GR/BL wire) to 41 on X6000 DME -> Signal HFM
#3 pin on MAF (RT/WS wire) to Voltage Supply
#4 pin on MAF (GR/WS wire) to 14 on X6000 DME -> Ground HFM
S54 Mass Air Flow Sensor
#1 pin on MAF (GE/BL wire) to 22 on X60003 DME -> Signal intake air temperature sensor
#2 pin on MAF (RT/WS wire) to 6 on X8680 Fuse Holder in E-Box -> 20A
#3 pin on MAF (BR/OR wire) to 17 on X60003 DME -> Ground HFM
#4 pin on MAF (RT/GN wire) to 7 on X60003 DME-> Voltage Supply
#5 pin on MAF (GE wire) to 1 on X60003 DME -> Signal HFM
As you can see, the 5 wire MAF has 2 voltage supplies. #2 is 12v and #4 is 5 volts. So this is how it can be wired:
S54 MAF Wiring to S50b32 harness
#1 to #1 on Intake Air Temp Sensor
#2 to #3 RT/WS -> 12v power supply
#3 to #1 BR/OR chassis ground
#4 to #1 on TPS Sensor -> 5v power supply
#5 to #2 MAF signal to DME
For E36 24v engine swaps you will need the following:
-The 5 wire MAF from a E46 M3, 01+ Z3 M, E39 M5, Z8, 99+ 540i, etc.
-The 5 wire MAF connector with pigtails
-Intake for 5 wire MAF
-Rerouting the signal wire for the intake air temperature sensor if you desire. If you want to keep your seperate IAT sensor leave #1 on 5 wire MAF connector disconnected.
The colors of the wires on your M5x or S5x harness may be different so double check your wiring diagrams. Also, the colors for the wires on the sensor plug may be different as well. I noticed the colors coming from the connector for the MAF on the 01 X5 4.4i are different, but they are wired the same.
I bought a cold air intake for the E46 M3 and I discovered the 4 wire round plug MAF for the E36 is too large to fit in the hole and is oriented 90 degrees. Instead of trying to modify the aluminum intake I looked into rewiring my S50 harness for the 5 wire MAF.
I found this posting on this 7 series forum on how to wire the MAF:
From the wiring diagrams I came up with the following:
S50b32 Mass Air Flow Sensor
#1 pin on MAF (BR/OR wire) to Ground
#2 pin on MAF (GR/BL wire) to 41 on X6000 DME -> Signal HFM
#3 pin on MAF (RT/WS wire) to Voltage Supply
#4 pin on MAF (GR/WS wire) to 14 on X6000 DME -> Ground HFM
S54 Mass Air Flow Sensor
#1 pin on MAF (GE/BL wire) to 22 on X60003 DME -> Signal intake air temperature sensor
#2 pin on MAF (RT/WS wire) to 6 on X8680 Fuse Holder in E-Box -> 20A
#3 pin on MAF (BR/OR wire) to 17 on X60003 DME -> Ground HFM
#4 pin on MAF (RT/GN wire) to 7 on X60003 DME-> Voltage Supply
#5 pin on MAF (GE wire) to 1 on X60003 DME -> Signal HFM
As you can see, the 5 wire MAF has 2 voltage supplies. #2 is 12v and #4 is 5 volts. So this is how it can be wired:
S54 MAF Wiring to S50b32 harness
#1 to #1 on Intake Air Temp Sensor
#2 to #3 RT/WS -> 12v power supply
#3 to #1 BR/OR chassis ground
#4 to #1 on TPS Sensor -> 5v power supply
#5 to #2 MAF signal to DME
For E36 24v engine swaps you will need the following:
-The 5 wire MAF from a E46 M3, 01+ Z3 M, E39 M5, Z8, 99+ 540i, etc.
-The 5 wire MAF connector with pigtails
-Intake for 5 wire MAF
-Rerouting the signal wire for the intake air temperature sensor if you desire. If you want to keep your seperate IAT sensor leave #1 on 5 wire MAF connector disconnected.
The colors of the wires on your M5x or S5x harness may be different so double check your wiring diagrams. Also, the colors for the wires on the sensor plug may be different as well. I noticed the colors coming from the connector for the MAF on the 01 X5 4.4i are different, but they are wired the same.