MR2 Roadster Owners Club

The Workshop => Maintenance, Problems & Troubleshooting => Topic started by: bobmcc13 on April 19, 2020, 12:19

Title: Crankshaft position sensor wiring
Post by: bobmcc13 on April 19, 2020, 12:19
Following problems that I had with a 1349 fault I was advised to check the wiring at the sensor, particularly the earth connection.
Sure enough I found the the connection was rotting away.
The connection was cleaned up and re-terminated.
While doing this job I found the the earth wire was rotting and every time I moved it the wire broke.
I decided at this point to replace the wire but found that it disappeared into a tube and climbed up behind the alternator never to be found.
Could someone on the Forum tell me where the other end of the earth wire is so that I can replace the length and re-terminate both ends with proper wire and terminals.
I hope all this makes sense and I thank you in advance.

Bob McC.
Title: Re: Crankshaft position sensor wiring
Post by: Carolyn on April 19, 2020, 13:24
The earth wire disappears into the wrapping and does not re-appear at the plug end. I'm loathe to slit my spare open to see what gives... The wiring goes to a two-pin plug that is clipped to the dispstick tube up behind the alternator.  It is possible to get at it - but it's a piglet.

Here's a pic of the sensor off the car.  Where the other end of the earth goes is a mystery....It does not make a circuit to either pin in the plug.

crank sensor.jpg
Title: Re: Crankshaft position sensor wiring
Post by: thetyrant on April 19, 2020, 13:33
As C says access is not good back there!  here is a pic i found of engine loom on SC forum which shows where the connectors go in that area, doesnt really help you but good reference for anyone working in that area.

Engine Harness.jpg
Title: Re: Crankshaft position sensor wiring
Post by: bobmcc13 on April 19, 2020, 20:35
Thanks for the info guys you have saved me many frustrating hours searching for a connector that isn't there.
It occurred to me that it could be a sort of earth shield around the red and white wires within the tube.
It will remain a mystery that warrants some research but no messing around under the car.
Thanks again for your help.

Bob McC.
Title: Re: Crankshaft position sensor wiring
Post by: 75W-90gbox on July 30, 2025, 13:22
MR2 MK3 W30 Crank sensor connector flying lead colour of plug and the socket, behind the inlet manifold, the lead from the sensor has a black connector which goes into a grey connector fixed to a bracket just above and to the right of the alternator, is this correct.