735i M30 5 speed Crank sensor

[HLF]

Howdy!

I have a 735i 5 speed and I get crank but I am not getting spark. I dont know if the cranks sensors can halt the spark but the crank sensor connections at the back of the block are FUBAR'd. The connectors on the sensor side of the harness (not at the sensor pigtail) are missing. Just the pins remain. I can plug the pins into the main harness connector.

Can the crank sensors halt spark?

I am trying to solve a no start issue.

TIA!

Kyle

[8991XJ]

The sensors are required to have the engine fire. They tell the engine when to fire.
Any good electrical connection to the correct harness connector for the two sensors should be fine.

[HLF]

I know it sends a signal for the motronic injectors but the ignition is on a single coil (beer can style) and mechanical distributor.

[Hit Man X]

Keith just said yes.

Replace the sensors already. One reads engine speed and other TDC. Replacing this will allow your vehicle to run again, provided there are no other issues which are possible.

The ignition switch is responsible for the power to the starter to spin the engine over.

[HLF]

okay, I misread the post. I thought he was speaking "generally". Thats why i tried to be more specific. Here is how I got the car. Does anyone have an idea of what pins go where? Pic attached

[8991XJ]

color of the wiring is in the ETM download one from the middle of the left column 1985 ...Electrical Troubleshooting Manual

http://www.e38.org/e23/

[8991XJ]

The issue here is that one is a reference (point) sensor and the other is a speed sensor and you can not connect them backwards and have the unit work. The parts are the same but you need to connect the Black boot to the correct location on the bell housing. Same with the Gray boot.

The speed sensor as specified in the ETM must connect to the Black connector going to the motronic unit and the reference sensor must connect to the Gray connector.

The tranny housing is marked as B and D for the two sensors. The Reference sensor goes to the B location and the Speed sensor goes to the D location.

So the Black Boot on top of the engine connects to the D location on the bell housing.

The Gray Boot on top of the engine connects to the B location on the bell housing.

Looking at the face of the connector with two bosses on the bottom and one boss on top, the pins are labeled 1, 2, 3

Pin 1 to 2 is 960±96Ω
Pin 1 to 3 is over 100,000Ω
Pin 2 to 3 is over 100,000Ω

Since 3 must be the shield, 1 and 2 will be the signal. This connects Black to Black in the top of engine connectors for both senders.

So just look at the wiring under the boot to verify you are going Yellow to Yellow and Black to Black.

[HLF]

The issue here is that one is a reference (point) sensor and the other is a speed sensor and you can not connect them backwards and have the unit work. The parts are the same but you need to connect the Black boot to the correct location on the bell housing. Same with the Gray boot.

The speed sensor as specified in the ETM must connect to the Black connector going to the motronic unit and the reference sensor must connect to the Gray connector.

The tranny housing is marked as B and D for the two sensors. The Reference sensor goes to the B location and the Speed sensor goes to the D location.

So the Black Boot on top of the engine connects to the D location on the bell housing.

The Gray Boot on top of the engine connects to the B location on the bell housing.

Looking at the face of the connector with two bosses on the bottom and one boss on top, the pins are labeled 1, 2, 3

Pin 1 to 2 is 960±96Ω
Pin 1 to 3 is over 100,000Ω
Pin 2 to 3 is over 100,000Ω

Since 3 must be the shield, 1 and 2 will be the signal. This connects Black to Black in the top of engine connectors for both senders.

So just look at the wiring under the boot to verify you are going Yellow to Yellow and Black to Black.

You're a wealth of information, thank you!