85 to 86 Intake temp sending units

[soldthedart]

I doing the 86 PE Intake, injectors etc.... The 85 had a single pin type temp sending unit on the bottom of the lower intake and the 86 has a 2 pin type.
My question is since I swapped the ECU will my 85 sensor work or not? I would obviously need to buy an adapter.
Is the lower one for the fan controller?
If so Ill just swap it in.
I know the one on top of the intake is for the ECU.
The one in the block below the oil sending unit is for the gauge.

[MikeFleming]

I know the one on top of the intake is for the ECU.
The one in the block below the oil sending unit is for the gauge.
Three separate, independent systems that have nothing to do with each other.

The cooling fan circuit is NOT managed (controlled?) by the EEC in the SVO. It's a separate circuit as part of the chassis electrical. The EEC knows nothing about a cooling fan.

You should keep the single-wire (push pin) fan switch and swap it over to the square intake lower. Be sure to install the fan switch sensor end into active coolant flow. Install it without teflon tape as the ground path is through the switch threads into the manifold, to the head, to the braided chassis-to-block ground cable on the firewall.

The one in the upper, rear block is for the gauge only, Not related to any other system and the very primitive SVO EEC is not aware of this either.

[soldthedart]

Mike,

So am I right about the sensor n the top of the lower intake being for the ecu?
The one in the block is for the gauge.
the single pin that I will reinstall per your recommendation is for the fan.
I will heed your instructions about the Teflon sealer.
The only place to instal the sensor is going to be where the original 2 pin was in the lower.
Im going to have to use an adapter, hopefully I will get enough coolant flow so I won't need to add a supplementary thermostat.

[MikeFleming]

The sealed 2-wire thingie in the middle top of the lower intake connects to the EEC as teh Engine Coolant Temp sensor, aka ECT. Most EEC connections use those water-proof type of connections.

The one in the lower coolant path of the lower intake is the cooling fan switch. It's a 2-wire on later models (power and return) while the earlier ones use a single-wire model (push-on stud similar to the gauge temp sensor (described below) and the oil pressure sensor. All of these single-wire (stud) sensors use the male pipe threads as the ground path for the sensor signal and need a very good path to ground - a mechanical metal-to-metal connection. Sometimes too much teflon tape will interfere with the electrical grounding function of the pipe threads on these sensors. Just be aware of this.

The one at the rear of the block, under the oil pressure sensor/turbo oil feed line adapter is the temp sensor thta feeds the dash gauge. It serves no other function and is not connected in any way to the EEC.

Remember that the SVO was one of the earliest Ford computer engine management systems and ONLY managed engine functions (Idle speed, injections, ignition timing, EGR, boost control). It has no idea there is a cooling fan, charging system, radio, AC, brake lights, air bags, GPS, ABS, traction control, gearbox selection, cruise control, etc.

Obviously we've come a VERY LONG way since then as far as complete automotive system management and assorted bus communications. The SVO is VERY primitive compared to today's cars.