Sensor confusion

[RickP]

I'm hoping someone can help me sort out some questions that have risen while building my cooling system. Originally my thought just wire the RF harness to a FFR fan thermostat switch but as I am learning more about the cooling system, my research has landed me on the ECT and cooling sensor. My understanding is an ECT tells the ECU the engine temp and the cooling sensor sends a signal to the water temp gauge.

Here's where I am having difficulty grasping the water pump and electrical connections. I am not exactly sure how to run the plumping from the pump to the engine. Upper passenger side outlet to the thermostat housing? Do I run the lower one to the first port on the lower intake where (insert sensor type here)?

What about a fan thermostat? The FITech EFI I plan to purchase has a provision to drive the fan via a thermostat, does the ECT provide for this? Lastly, do I need to route the heater outputs at all? I know Breeze has an elbow for the top heater outlet and another for the bottom that runs to the front port on the intake with a provision for an ECT. I am really confused at this point and any guidance would be much appreciated.

[wallace18]

Your temp sensor for the FI Tech unit will run the EFI and fan relay circuit as shown in the directions for the FI Tech. The sensor for the gauges will run the temp gauge. PM me if you have more questions, TW what type of engine are you running? I can help you better if I know that.

[RickP]

Your temp sensor for the FI Tech unit will run the EFI and fan relay circuit as shown in the directions for the FI Tech. The sensor for the gauges will run the temp gauge. PM me if you have more questions, TW what type of engine are you running? I can help you better if I know that.

PM sent

[karlos]

Just recently did the heater hose and temperature sensor installation myself. Thought a couple pictures might help.

The first shows the heater hose and bypass hose routing. The second shows the position of the two temperature sensors, one of which drives the temperature gauge and the other that provides info to the ECU/fan. Note that you'll need three ports in the intake manifold and/or thermostat housing: one each for the two sensors and one to provide coolant flow to the heater core. You'll probably also need a 45 or 90-degree fitting to attach the heater hose to the port in the manifold (can see it pretty well in the second photo).

Assuming you're using FFR-supplied gauges, you should have everything you need to drive the temperature gauge (gauge, sensor, and harness). Install the sensor in one of the manifold ports and then run the supplied harness from the sensor to the gauge. That's it. The second sensor should have been included with your EFI system. At least it was in my case, along with the harness that feeds the signal to the ECU. The only other wrinkle was an additional wire from the ECU harness to the electric fan. If yours is the same, you won't need the fan or thermoswitch wiring that's part of the Ron Francis chassis harness.

[phileas_fogg]

Thanks Karlos; those pictures are super helpful.


John

[jwsnake56]

If your manifold does not have enough ports in the front water passage (my Edelbrock Performer only had two) you can either get a filler neck that has a 1/2" npt port in it or you can make one in a neck like the one shown in the picture above. Look right below the "IN" in the HEATER INLET notation. See the round divot in the neck. I looked up the size drill I would need to tap a 1/2 npt thread and got it at Lowe's. At Harbor Freight they had a cheap 4 piece set of taps for NPT threads. I put the filler neck in the vise for my drill press and bored out that divot then with a LOT of arm strength ran the die to cut the threads.
IMG_0443a.JPGIMG_0445.JPG
I installed the thermostatic switch for the fan in the port in the filler neck and the gauge sender in the second port in the intake manifold. You can see it in the one picture right behind the distributor advance diaphragm.
I like the hoses that Karlos used. Where are they from?
John S.

[RickP]

Thank you Gents. Between the pics provided and some guidance from Wallace18, I have a clear picture (no pun) of what's needed. I have two ports on my intake and although I am not running a heater core, Breeze part#7540 looks like it will help me avoid drilling/tapping the thermostat housing

http://www.breezeautomotive.com/deta...=464&cat_id=17

[RickP]

OK - one last question. When referring to a ECT sensor (Engine Coolant Temperature) sensor, the FITech system I plan to purchase says it includes an IAT (Intake Air Temperature) sensor. Does anyone know if these are the same devices?

[wallace18]

OK - one last question. When referring to a ECT sensor (Engine Coolant Temperature) sensor, the FITech system I plan to purchase says it includes an IAT (Intake Air Temperature) sensor. Does anyone know if these are the same devices?

No they are not. The IAT is part of the FI unit. No need the install anything. I just installed the 600HP FITech unit to my MK4 and it is fantastic. You will love it.

[CraigS]

No they are not. The IAT is part of the FI unit. No need the install anything. I just installed the 600HP FITech unit to my MK4 and it is fantastic. You will love it.

Agreed. The air temp sensor will be somewhere in the throttle body and will connect directly to the ECU.

[ThickCobra]

I have a related question for my carburetor engine. The speed hut gauge directions instruct to install the sensor for the water guage at the lower passenger side of the block toward the rear. Is this not a good idea?

[RickP]

No they are not. The IAT is part of the FI unit. No need the install anything. I just installed the 600HP FITech unit to my MK4 and it is fantastic. You will love it.

I got the FITech EFI4 delivered yesterday. In looking at the installation instructions, I see timing control is offered if using a two wire distributor. I have a MSD ready-to-run distributor and I am cannot envision how to mate up the two plug connection to the dizzy ignition module. Blue wire from EFI to neg side of coil to ignition module on dizzy. Do you folks just add a pin connector at the end of these connections or is there a "plug" I can use.

Also, where exactly are folks placing the O2 sensor.

[wallace18]

I got the FITech EFI4 delivered yesterday. In looking at the installation instructions, I see timing control is offered if using a two wire distributor. I have a MSD ready-to-run distributor and I am cannot envision how to mate up the two plug connection to the dizzy ignition module. Blue wire from EFI to neg side of coil to ignition module on dizzy. Do you folks just add a pin connector at the end of these connections or is there a "plug" I can use.

Also, where exactly are folks placing the O2 sensor.

I did not use the timing control with my FITech unit. Just wire up you ignition as per manufacture's instructions or contact FITech on if you can use their timing control with your ignition setup. I put my O2 sensor in the passenger side pipe after all 4 pipes come to the collector. If you are using J-Pipes put it in one of them.

[RickP]

I did not use the timing control with my FITech unit. Just wire up you ignition as per manufacture's instructions or contact FITech on if you can use their timing control with your ignition setup. I put my O2 sensor in the passenger side pipe after all 4 pipes come to the collector. If you are using J-Pipes put it in one of them.

I don't think having the timing control option available is all that significant. Certainly doesn't warrant going with a 2 wire distributor. if you have a pic handy of the sensor location, please share but I'm fairly certain I can visualize where you have it located.