Contents
What causes low CHT?
Things that affect EGT Leaner mixtures cause EGT to decrease simply because less fuel produces less energy. Richer mixtures also cause EGT to decrease because excess (unoxidized) fuel absorbs heat energy when it vaporizes.
How do you lower CHT?
You can manage the CHT by increasing or decreasing the power and/or changing the fuel-air blend by leaning or enriching the mixture.
How does a cylinder head temperature gauge work?
The metal closest to the spark plug is called the hot junction and the other close to the head cold junction. The ring under the spark plug is used to transfer the heat from the plug to the thermocouple. The gauge and cold junction are usually calibrated at room temperature 72 °F (22 °C).
How does a CHT sensor work?
A basic description of the sensor is that it is a thermistor device in which resistance changes with temperature. As the temperature increases the resistance decreases causing a voltage drop to occur on the 5 volts signal wire. The PCM receives the various voltage signals and equates it to a temperature value.
What causes EGTs to rise?
As we pointed out earlier, high EGTs are the result of too much fuel for the available air. If you see EGTs climbing over 1300º F., the fastest way to reduce the amount of fuel going to the engine is to back off the accelerator pedal. Another possible solution is to downshift if your speed permits it.
Where is the CHT sensor located?
The Ford Transit cylinder head temperature sensor, or CHT, is used in the same way an engine coolant temperature sensor is. Located next to the cylinder head toward the back of the engine block, it monitors the temp of the head and sends this data to the van’s main computer.
What causes a cylinder to have low CHTS?
A cylinder problem An exhaust valve that’s not fully closing can cause low CHTs – your mechanic can confirm this with a borescope (or a compression test — they’ll hear air escaping through the exhaust if the valve isn’t closing).
Is it safe to turn off CHT on all cylinders?
Slightly reduced CHT on all cylinders. Consider confirming by doing an in-flight mag check, but be careful – if you turn off a mag and the engine quits, pull the mixture control before turning the mag back on to avoid possible afterfire-damage to the exhaust system.
How are individual CHTS affected by engine problems?
Individual CHTs or banks can be dramatically affected by engine baffle issues/problems as well. Some indications of trouble are shown in the example displays below.
Do you need an engine monitor to measure CHT?
You obviously need an engine monitor to measure the CHT of all six cylinders (or twelve if you fly a twin). If all you have is the factory CHT gauge, then all you know is the CHT of one cylinder (and only very approximately at that) – you have no idea how hot the other five are running.