M42 sensors (all of them)

[AGF101]

hello everyone,

Im new to the forum and I need help. The thing is that i have a 95 318I(love that car), but last year my engine went out and i decided to swap it out for another m42 but now i dont know where all the sensors go. I took pictures with my phone but i got sort of busy at the time with school and work and by the time i was back to work on my car i had changed phones and i cant find the chip from my other phone(<--thats a hell of a run on lol). so now im not sure were all this sensors go or how this dumb engine work, too many sensors and it makes less hp than a honda
 
Now, i like this car because is rwd and its a lot of fun and i dont want to sell it, a diagram with a pic of the sensors would be awesome. to this point i need to connect the alternator, starter motor and all the sensors that surround the engine.

[DRTE30]

I am not sure if you're aware with realoem.com ?  There you can put in the last seven digits of your VIN number and it will spit out all the exploded diagrams with most all of the part numbers you will ever need.  It is incredibly useful.  Your second option is to find one of the many places online who has a .pdf version of the Bentley Manual for your car and application.  That is an awesome resource as well and you should have it irrespective of using it often or not.  The Bentley may mention the actual color of the sensor in question per respective application/installation area, but realoem.com does not have colored diagrams, so it is worthless in that regard.

[jwalton]

I think that locating the sensors isn't nearly as bad as verifying the proper operation of the sensors.  I would like to add information about testing and ensuring the accuracy of the sensors for the e30 m42.  I have recently torn my m42 apart again in order to clean it up and double check everything.  I am trying to find information to test each electrical component, but in my searches I have gathered much more confusion than results.  I can post what I have found here, but I would need help from others in order to verify my measurements.

[DesktopDave]

Sensors are easy.

Remember to only perform continuity or resistance (ohms) tests on components and sensors...NEVER on wires heading to the DME or cluster! Only test voltage on the DME wires. Unplug the DME to run continuity test on wires!

Crank position sensor - 680ohms(+/- 10%) between pins 1&2. Pin pairs 2&3 and 1&3 must be over 100Kohms. Sensor tip must be clean of oil residue and metallic debris, and must have an air gap between head and sending wheel not more than 1.3mm (roughly as thick as a credit card).
Cam position sensor - 1240ohms (+/-10%) between pins 1&2. Pin pairs 2&3 and 1&3 must be over 100Kohms

Coolant temp sensor (ETC) harness pin 1 (brown/red wire) must have 5VDC with ignition switch on. The sensor is variable resistance NTC; should be very high resistance if cold, dropping as the coolant warms up. BMW spec is 7-12Kohms at 14degF, 2-3Kohms at 70degF, 270-400 ohms at 180degF (operating temp). Be aware that there is also a gauge coolant temp sender in the E30. It has one pin on the sender. There is also an oil pressure sender plug in that harness...all three have the same style two-pin connector. Don't mix them up! E36 is similar, but it uses a dual-output engine temp sensor (ECT).

Airflow sensor (AFM) harness must have 5VDC between harness pin 1 and ground with ignition switched on. Pins 1&2 on the AFM will have a steady & variable resistance (ohms) as the door is moved through its travel. While you're there, test the intake air temp sensor (IAT). Pins 4&5 on the AFM should have 7-12Kohms resistance at 14degF, 2-3Kohms at 70degF. resistance will drop as the air temp gets higher.

Throttle position sensor is easy on the E30. With the ignition on, you'll need to have 5VDC between on pin 1 in the harness and ground. If the throttle is closed (idle position) you should see zero resistance (continuity) on sensor pins 1&2 and infinite resistance on pins 2&3. As you open the throttle plate, pins 1&2 must switch to infinite resistance. Move your DMM leads to pins 2&3. They must have infinite resistance until the throttle is almost fully open (WOT), at which point you'll see zero resistance. Be sure to test the TPS while it is installed on the TB - switch mis-adjustment, throttle cable too tight or a sticking throttle plate can prevent it from working properly. There are two slotted leads that permit limited adjustment of the TPS. I usually clean the TB with some alcohol/TB cleaner and a few shop cloths while I'm testing it out.
An E36 sensor is similar, but with a variable resistance. It'll also have 5VDC on harness pin 1. TPS pins 1&2 should increase resistance from 1-4Kohm as the throttle opens, pins 1&3 should read out approx. 4Kohms. Be aware that there is also a secondary TPS on E36 models with traction control...I'm not sure if the M42 models had this option or not.

The O2 sensor isn't easy to test properly. You can attempt to troubleshoot it with the following tests. The O2 sensor will output a rapidly fluctuating 0.2-0.8VDC signal when fully heated (>300degF) on pins 1&2 (be aware of dangerously hot components if attempting this test). Pins 3&4 on sensor harness (heater circuit) must have continuity. There must be battery voltage on pins 3&4 in the engine harness when the ignition switch is in position II.

Fuel pump must output 3.0 bar (43.5psi) +- 10%. The proper way to test the pump is with an inline tee fitting on the supply side of the fuel rail, or at the pump output under the rear seat. With the ignition on, you'll have to jump terminals 30 & 87 in the fuel pump relay socket to power up the pump. If you connect the pump directly to the testing gauge (known as 'dead-heading' the pump), you'll get an incorrect reading. A healthy pump can put out 80psi. Keep the gauge connected for at least 20 minutes; the system should lose no more than 0.5 bar (~7psi) pressure. If so, the pump's internal check valve is worn.

Ignition coils must have very low primary resistance - 0.4 to 0.8 ohms between the outer pins on E30 coils (Bosch calls them terminals 1&15). Similarly, the E36 quad-coil pack must read 0.4ohms to 0.8 ohms between the following pairs: 2&1, 2&6, 2&7, 2&5. Secondaries cannot be tested with a DMM.