Hi guys. I ve been running really rich lately, till the point where after 30 mins of driving the spark plugs are so fouled up that the engine dies out. So i figured it must be my coolant sensor (since the ecu codes tell me ).

I pulled out my trusty multimeter and tested no resistance at all in the sensor. I figured it must be broke? i tested the rest of the circuit not including the sensor and still cant get any continuity. Has anyone got any ideas other than following the wires into the maze they dive into? And how do i take out the sensor with a regular toolkit? (its a very tight fit). thanks for yours help

that sensor is right next to the thermostat IIRC. Shouldnt be any problems getting to it. If you arent getting continuity at the wires, I'd check the wire. Subaru uses a really crappy setup on the intake wiring. They get hot and brittle, crack and corrode.

 

I think the sensor is a 17mm head... or a 14mm one of the two

that sensor is right next to the thermostat IIRC. Shouldnt be any problems getting to it. If you arent getting continuity at the wires, I'd check the wire. Subaru uses a really crappy setup on the intake wiring. They get hot and brittle, crack and corrode.

 

I think the sensor is a 17mm head... or a 14mm one of the two

 

ECU Coolant sensor is the one behind the intake manifold, near the knock sensor.

 

To the OP, somewhere around here is a chunk of the 89 FSM. The engine wiring diagram and specs are there as well, I think.

 

Being for an 89, not everything will apply to your 86. At least not in the wiring department. But it is very possible the coolant temp setups are the same.

... I pulled out my trusty multimeter and tested no resistance at all in the sensor. I figured it must be broke? i tested the rest of the circuit not including the sensor and still cant get any continuity. Has anyone got any ideas other than following the wires into the maze they dive into? And how do i take out the sensor with a regular toolkit? (its a very tight fit). thanks for yours help

The sensor shows infinite ohms? Is this before or after you scraped off all of the corrosion? I can't remember what the specs are for the early CTS, but it should be pretty much the same as the 89 CTS. Chilton's, which I think confused the CTS with the temp gauge sender, claims 180ohm-25ohm (ambient-212F). FSM for a 92 Legacy specifies 2.5Kohm-500ohm (ambient-212F).

 

As far as the wiring, are you using a regular ohm/multimeter to test for continuity across the 2 wires of the connector? If so, this reading is likely to be meaningless due to the semiconductors at the other end of the wire(s). Even if you are using a diode-test function, it is still likely to be unhelpful.

88 XT FSM claims 11.5 kOhms - 700 Ohms for 14F to 122F

88 XT FSM claims 11.5 kOhms - 700 Ohms for 14F to 122F

This is in the Fuel section and not the Cooling section? (CTS and not temperature sending unit, right?)

This is in the Fuel section and not the Cooling section? (CTS and not temperature sending unit, right?)

Yes, its for the Thermosensor, and its in the Fuel system section.

youre gonna need a 17mm deep well socket, fyi.

thanks alot for the info guys

 

The sensor shows infinite ohms? Is this before or after you scraped off all of the corrosion? I can't remember what the specs are for the early CTS, but it should be pretty much the same as the 89 CTS. Chilton's, which I think confused the CTS with the temp gauge sender, claims 180ohm-25ohm (ambient-212F). FSM for a 92 Legacy specifies 2.5Kohm-500ohm (ambient-212F).

 

As far as the wiring, are you using a regular ohm/multimeter to test for continuity across the 2 wires of the connector? If so, this reading is likely to be meaningless due to the semiconductors at the other end of the wire(s). Even if you are using a diode-test function, it is still likely to be unhelpful.

 

can anyone second this opinion? yes i am using a regular multimeter, but i cant get a continuity buzz even when i test the clean end of the circuit (on the connecter side to the coolant sensor) - i thought maybe the ignition has to be on , is this the case? does anyone know a good estimate on how much a sensor will cost?

thanks again