Ford 2.3L Turn UP the Heat

There's quite a few things that you can do that affect the temperature of the engine and increase gas mileage and performance. The electronic fuel injection runs in enriched mode (choke mode - buring extra fuel) until 190 degF. The key is to get the engine up to temperature as fast as possible. The engine also likes to run hotter than normal engines. A normal engine sits around 190 degF, this one likes to be around 210 degF.

The 2.3l loves to run hotter than most engines. My temperature gauge reads C - NORMAL - H, during regular driving, it barely leaves C and after a long time (30 minutes or more) it'll final get to N. This means that I'm running in enriched mode for most of my driving and wasting gas.

As a test, I put a piece of cardboard in front of the radiator to block about 1/2 of the radiator. For two gas tankfuls, I drove around in about 50 to 75 degF weather. The engine warmed up way faster in about 10 minutes and idled around the R mark on normal. My gas mileage JUMPED to 25.58 mpg (Imperial gallons, slightly larger than American gallons) with NO effect on performance. In a hotter climate, you may want to cover LESS of the radiator if you go this route. Just a note: hotter is not always better -- so don't try to run your engine with the coolant boiling over! You will NOT get better gas mileage, there are limits. The engine may seize and damage itself!

Here's some basic concepts on the engine cooling system:

  • The thermostat determines the minimum temperature the engine will run at.
  • The radiator cap is pressurized at 16 psi so that you can run hotter engine temperatures without boiling over.
  • The fan, fan shroud, coolant, radiator and airflow through the rad work together to limit the maximum temperature the engine can run at. If one of these is out of whack, then the engine will overheat.
Here's some things to try that are a more permanent solution:

Run the Engine Hotter - The 2.3l loves to run hotter than most engines. How do you make it run hotter? Change the thermostat to a hotter temperature spec. Unfortunately, there are only two available for the 2.3l engine: 180 degF (way too cold) or 192 degF (not hot enough). So what do you do? Well you can do the one of these two:

Change to an electric fan - The mechanical fan robs you of 5 to 10 hp at highway speeds. The engine is powering the fan for no reason, the air moving at 20 mph and up is more than adequate to cool the rad. An electric fan is only on when you need it. I've purchased an electric fan and just installed a radiator temperature switch to use. In the next couple of days, I'll be installing the fan.

Coolant Temperature Sensor - The coolant temperature sensor is read by the computer to determine when to go off choke mode and to programmable fuel injection. If your 2.3L temperature gauge reads low like mine - just barely into the normal range when warm. You are going to waste fuel as the computer thinks that the engine is still cold long after its warmed up and adds more fuel than needed. I'm replacing my local parts store sensor with one directly from Ford - that should fix this problem.

Surprisingly, none of the wiring diagrams for 90s and up Rangers, show where the temperature gauge receives its signal from. I started researching this after I saw a guy selling a power module for the 2.3L engine on ebaymotors. The module goes between the coolant or air intake temperature sensor. Most likely a resistor to fool the engine into thinking that it is running cooler so it richens the fuel/air mixture.

But where does the temperature gauge get its source? On my Ranger,the temperature sensor is located on the heater hose! It should be located in the BLOCK!

Air Intake Temperature Sensor - The computer reads the air intake temperature and adjusts the air temperature to 70 degF - ideal temperature for the 2.3L according to the sources I've read. The computer uses the air from the exhaust heat riser to control the temperature, there's a valve in the air intake to select fresh air or air heated from the exhaust. With the K&N style filter, the air inlet temperature sensor is really just measuring the engine compartment temperature. I eventually drilled a hole in the cone style filter and screwed the sensor inside. Much better response. Read about how I replaced the air inlet temperature sensor with a 10 cent part to improve gas mileage and smooth out the engine.

Bleeding the Coolant - A lot of the "no heat" from the heater or temperature problems can be caused by air trapped in the engine where coolant should be. Here's where you find out the trick to getting heat out of the 2.3L engine.

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Copyright March 2011 Eugene Blanchard