What is the sensor in the back of the head on a 960? on my wiring harness the wires have been desconnected from the clip that plugs in to the sensor,

 

At the rear of the head, there is at the top on a bracket, the cam sensor and rpm sensor, and a single female plug for a voltage test for the ignition system.
Then depending on the year, there is a temp sensor for the ecm thru '95. Then the sensor was moved to the t stat and controlled both the dash gauge and ecm.

DanR '94 964 356,000 miles (122,000 on the new engine)

 

is a large plug that is right below the cam sensor looks like it goes into the head like a temp sensor..?

 

must be the coolant sensor since it is an 92, how ever is the sensor absolutely necessary? one of the plugs broke for the sensor

 

The plug for that temp sensor at the back of the head is required, it reports to the ecm for fuel management.

You will have to replace that connector on the wire harness to get it to work.

DanR

 

FWIW, it's the same plus as the coils. I just had to replace one on mine too.

 

are there similar plugs on say a 740 i could use? just the end clip, which wire goes to which side.

thanks again

 

Not sure, this is my first volvo. I wish I would have thought about motor swapping when I first bought this car rather than dealing with Volvo's sub-par wiring, etc. Would have been cheaper long-term with the significant increase in fuel economy of an LS-based engine, etc, parts, etc.

 

anyway can anyone tell me which side which wire goes to clip side up?

 

Are you asking about the two wire that lead to a coil?

I believe there is a plus sign and minus sign on the coil itself, there is a common color wire to the coils, that would go to the minus sign side, the plus wires are individually colored.

I have crossed those wires before and it causes a misfire, engine runs much better when wired correctly.


DanR

 

I was referring to the coolant temp sensor on the back of the head as I have to rewire mine

 

anyway can anyone tell me which side which wire goes to clip side up to the coolant temp sensor on the back of the block, itd be much appreciated