Crumbled Connector, Crankshaft Position Sensor?

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Hutch
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Location: Lancaster, PA

Crumbled Connector, Crankshaft Position Sensor?

Post by Hutch »

Hi All

New to the BMW world and specifically the e24 and am thus still learning my way around the engine bay. I picked up my car a few months ago and have begun addressing the various maintenance items and thus am in the midst of doing the plugs, distributor, etc.

I either bumped it with my arm or it just crumbled in the breeze but I was reinstalling the distributor tonight and noticed this connector was snapped off and upon disassembly it just crumbles in my fingers.

Can you wise folk confirm this is the CPS? I actually have some other Bosch CPS from my Saabs that I may try to harvest the connector from, but assuming that is indeed the CPS I think that is $60 well spent as it is likely due for replacement anyway if it was that old.

Thanks in advance!

This one, right:
https://www.fcpeuro.com/products/bmw-cr ... 0261210002

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hornhospital
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Re: Crumbled Connector, Crankshaft Position Sensor?

Post by hornhospital »

That sensor serves no function but reading the crank position when the factory/dealership diagnostic tool is plugged in. You can safely eliminate it completely.
Ken Kanne
'84 633CSi "Sylvia"; '85 635CSi "Katja";'85 325e "Hazel Ann"; '95 M3 "Ashlyn"
Hutch
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Location: Lancaster, PA

Re: Crumbled Connector, Crankshaft Position Sensor?

Post by Hutch »

Thanks for confirming! I did some more digging around last night and came across this post that says the same, that is hilariously overkill that they have a whole sensor just for TDC diagnostic, god bless 80's engineering! :mrgreen:
cecotto479 wrote: Mon Feb 15, 2016 9:19 pm People get confused by the "crankshaft position sensor".

The pre Highline Motronic cars have two sensors performing the function of a crank position sensor. These are mounted in the gearbox bellhousing. Either can fail and cause a no start. Though when the speed sensor goes, the car often starts and then dies very quickly, the position reference sensor causes loss of spark when it fails.

The confusion arises in that these engines also have a front mounted sensor on the crankshaft pulley that looks like a crank position sensor. It does nothing in terms of the engine running. It only reports TDC to the diagnostic socket.

I've often had people seeing the wiring to this in a poor state and assuming that that is what is causing their no start.

The part number you have provided is this TDC indicator.

IT WILL ABSOLUTELY NOT CURE YOUR NO START ISSUE.

If your crank pulley does not have a toothed wheel, the sensor at the front does nothing and your "crank position sensor" is the two sensors in the gearbox bellhousing.

If your crank pulley has the toothed wheel, you have a front mounted sensor that does the work of the two gearbox sensors and no gearbox mounted sensor.
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Ralph in Socal
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Re: Crumbled Connector, Crankshaft Position Sensor?

Post by Ralph in Socal »

What year is your car? The front crank sensor is critical to engine computer functions for the B35 Motronic 1.3 system in 88 and 89 cars. Some 87 cars run the B35 configuration as the upgrade was implemented at the factory earlier that the model year change

Ralph
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Salawada
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Re: Crumbled Connector, Crankshaft Position Sensor?

Post by Salawada »

Hello,

I am trying to find a part that my mechanic ia having tough time tracking down. Issue with my 1987 635csi (pre 87 build) was a lack of power and an issue with fuel not igniting in the engine but instead turning my catalytic converter (or other part) or my exhaust bright red. I changed the spark plugs and wires and no change. Mechanic says 2 of the fuel injectors are bad and the front crankshaft sensor. I believe its part number 12141275644 but realoem says its been superseded by 12141708619 pulse generator?? The male ends are not the same.

Salawada
1987 635csi
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