Mounted at rear of valve cover, two wires but nothing below it. Valve cover is not correct for an e9.
What Is This? On a 74 3.0CS Auto.
- Thread starter HB Chris
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I agree but what could it be monitoring?
Where do the wires go to?
Into a sleeve!
From what I see on the wiring diagram that have two brown and black kindish wires is the voltage dropper for A/T position indicator.
If this is that, on my 2800 auto, there is a resistor by the pedals, that dims the auto lights on dash when the main light switch is turned on.
If this is that, on my 2800 auto, there is a resistor by the pedals, that dims the auto lights on dash when the main light switch is turned on.
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What's on the underside? Any non-oem gauges in the car?
Well, it looks like a VDO temperature sensor that is designed to send a voltage that varies based on resistance to a gauge. Normally, these are mounted in the flow of either coolant or oil, and in such a way as to ground the body of the sendor. This one appears to have a ground ring under the sender and does not appear to be mounting into either an oil or coolant flow. I'm not sure what you would monitor in this location.
Ambient air temp sensor.
It could be but there is no probe below it. 2002s used a similar temp probe but under/inside the intake manifold.
VDO marks typically the parameters and part number on the sensor body. It is also partially visible on the picture (but out of focus). If possible you could read out the text stamped around the sensor.
That might help to discover the circuit behind.
That might help to discover the circuit behind.
I also think it must be a temperature sensor. It might be specifically for the late model emissions stuff that is nearby. It seems a bit crude if it is just measuring the ambient air near the engine as apposed to the engine or exhaust directly. But weren't these emission systems rather hastily designed for the American market?
After some investigation (as US market is specific) it is very possible to be a temperature switch:
from: https://e9coupe.com/forum/threads/vacuum-hose-colors.10503/
On the BMW Part list thermal switch is not allocated:
I would expected it should be mounted onto the thermostat housing but if the engine is a mod everything is possible, including thermal switch mounted on a piece of metal as such solution would not rather be BMW-made.
from: https://e9coupe.com/forum/threads/vacuum-hose-colors.10503/
On the BMW Part list thermal switch is not allocated:
I would expected it should be mounted onto the thermostat housing but if the engine is a mod everything is possible, including thermal switch mounted on a piece of metal as such solution would not rather be BMW-made.
Definitely a temp sensor and hooked up to the emissions dashpots/vacuum lines. 74s have three dashpots, can’t remember if 73s have two or three so mystery solved.
The factory wiring diagrams don’t include emissions related equipment unfortunately.
One's might expect someone from classic Bimmer scene should have been drawn it in the past.
There should also be "BMW Service" note telling more about the system, wiring and way of operation as BMW Dealers in US were responsible for repairs keeping these systems working.
There should also be "BMW Service" note telling more about the system, wiring and way of operation as BMW Dealers in US were responsible for repairs keeping these systems working.