How did your guages work with the new engine?

[rs4pro3]

that rounds plug is the c101 plug search on here for many different wiring diagrams posted. As for your automatic harness, good luck. George started with one but couldn't get it to start and swapped to the E30 engine harness.

[Psychomofo]

Well, I guess I should update this thread with some results of my automatic wiring harness on my '89 M30 in my '84 318i. Basically, all I did was match up the wires that were the same color. Car fires right up, and runs pretty much perfect. My only issues are: no tach signal and my coolant temp sensor not reading. I've tried the 318's sensor, but it didn't work either. I do have about 5 green w/ yellow stripes, and one white wire with a blue stripe left over on the chassis harness. I also have about 10 left over on the M30's harness. Everything works great except for the tach. and coolant gauge. I'm still working on these problems now.

[flawdaboi407]

I have a 84 318i also and need to figure out where to slpice the #9 black wire on the e32 harness. also which temp senders to use? thanks.

[Doughnut]

While we're on the subject. I've got a few concerns myself. I've got the wiring harness, computer, and motor from an '89 735i automatic. It's all going into an '84 318i. One big problem is the fact that there is no big round plug on the '84. Anyone got any ideas for that, other than robbing the plug from another car and then splicing wires on the car onto the plug? Also, how will the sensors and TPS work in my car since I'm going to be using a manual tranny? Seems to me that the TPS won't matter as it just won't have anywhere to send the signal, but it shouldn't affect how the motor actually runs, right? Sorry to hijack the thread, but I felt it was relevant. :P

318i harness:

#1 - BL : Alternator
#4 - BR/VI : Coolant temp sensor
#6 - GN/GE :
#7 - R/VI : Fuel pump
#8 - SW/GE with another small SW/GE : Starter
#10 - GN : Coil
#16 - SW/BR : Oil pressure switch
#17 - WS/BL : Diagnositic port.

e34/e32 harness:

Pin 1, BU goes to the alternator. Comes from the Instrument Cluster "charge indicator" light. BU in the fuse box.
Pin 2, GN/YL comes from oil lever sensor. It is BU/BK in the fuse box and runs to the static oil level active check control unit, which is the same as the oil level light.
Pin 4, BR/VI comes from the coolant temp sender unit. It is BR/VI in the fuse box and goes to the Instrument cluster temp gauge.
Pin 5, BR/GN Oil pressure switch. Runs to instrument cluster oil pressure light.
Pin 6, GN/WH goes to the O2 sensor heater relay. Gets power from fuse 9 and in the fuse box is colored GN/YL.
Pin 7, GN comes from the ignition switch and goes to the Start Input, in the motronic unit and it also goes to Pin 15 on the coil. In the fuse box it is colored GN.
Pin 8, WH/BK comes from the motronic unit "present fuel rate output". Is YL/WH in fuse box and runs to Fuel Economy Gauge in the bottom of the tach.
Pin 9, BK goes to the ECU Engine speed output. This is BK in the fuse box. On the E28 this actually should be the connected in C103.
Pin 10, BU comes from the oil level sensor. It is VI/GN in the fuse box and goes to the active check control unit as the dynamic oil level light.
Pin 11, WH/GN comes from Pin 7 of the diagnostic connector. Is WH/BU in the fuse box and goes to the Service Indicator Processor.
Pin 12, GY comes from the ECU and is the trigger for the "Check Engine" light control. In the fuse box it is BR/BK. This wire is not used on the E28, since there is no check engine light.
Pin 13, GN/VI comes from Pin 87 of fuel pump relay. Is VI/RD in fuse box and runs to Fuse 11.
Pin 14, BK/WH comes from motronic unit "Speed Signal Input". Is BU/YL in fuse box and goes to the Speed Input of the Instrument Cluster.
Pin 15, BK/GN comes from Pin 30h on the coil. In the fuse box it is BK/GN and runs to the unloader relays.
Pin 16, WH/BK comes from Pin 6 of diagnostic connector and is used in the SRS system. In the fuse box it is WH/BK and is said to be not used.
Pin 18, BK/YL is the starter trigger and comes from in the car. It is also BK/YL in the fuse box. It also runs to Pin 11 of the diagnostic connector.
Pin 20, RD/YL comes from Pin 87 of the main relay. It is RD/YL and goes to power the ABS Hydraulic Unit.

This should all be pritty much relative to your swap.

You CAN use the automatic ecu and harness with your swap... I did, and it worked fine.

[Jean]

Curious if you guys got your gauges figured out? What sensor did you end up using?

I want to order the right one as my temp gauge is dead with the brand new e32/e34 b35 sensor.

[LowR3V'in]

Match the sensor to whatever matches the gauge in the cluster.
Same with whatever one matches the ecu.


M20 cluster, m20 sensor.
M30b35 ecu, m30b35 sensor.

[drift]

Match the sensor to whatever matches the gauge in the cluster.
Same with whatever one matches the ecu.


M20 cluster, m20 sensor.
M30b35 ecu, m30b35 sensor.

Tried e28 528e (eta motor = eta car) coolant temp sensor,still no luck.
Tried new e34 535i coolant temp sensor, still no luck.
Jump the wires, temp gauge goes all the way up.

[Jean]

That was my thought as well, I'll move the m10 temp sender and check again.