What EGT sensors are good for
An EGT probe is a thermocouple that sits in the exhaust stream right after the port. It reacts quickly to changes in mixture and timing, so it's useful in three ways:
- Tuning: with a probe in each runner, you can see which cylinders run hotter and trim fuel or timing per cylinder.
- Logging: a record of how hard the engine worked on each pass or session.
- Protection: a warning or fault code when temperatures go past where parts start to suffer.
Depending on the model, an Elite can read up to 12 EGT channels.
Two ways to connect
Thermocouples produce a tiny voltage that an ECU can't read directly, so every EGT setup needs an amplifier. You can use either:
| Haltech TCA box over CAN | Aftermarket amplifier to an AVI | |
|---|---|---|
| Input Type | Thermocouple Type K | Analogue Voltage |
| Uses ECU inputs? | No, it communicates over CAN | Yes, one AVI per channel |
| Calibration | Handled for you | You enter the amplifier's calibration |
| Fault codes available | Operating Max | Raw Min, Raw Max and Operating Max |
We recommend the TCA route. The TCA2 handles two probes and the TCA4 handles four. Both leave your analog inputs free for pressure and temperature sensors. Pair them with a Haltech probe such as the 1/4 in open-tip thermocouple.
Setting up the input
With a TCA box
- Enable the TCA in Main Setup > Devices first. See our Devices article for the Box A and Box B choices.
- In the EGT function's Wiring tab, set Input Type to Thermocouple Type K.
- Pick the TCA channel your probe is plugged into as the Exhaust Gas Temperature Input.
With an aftermarket amplifier
- Set Input Type to Analogue Voltage.
- Assign an AVI as the input and wire the amplifier output to it.
- Enter the amplifier's calibration on the Calibration tab (details below).
Display tab
| Setting | What it does | Our advice |
|---|---|---|
| Warning Minimum | EGT readouts in ESP flash red below this temperature | Useful for catching a cylinder that has stopped firing, since a dead cylinder runs cold |
| Warning Maximum | EGT readouts flash red above this temperature | Set it to what's safe for your turbo, manifold and pistons, not a generic number |
| Display Minimum | Lowest value EGT gauges show | Display only. The sensor still reads the full range |
| Display Maximum | Highest value EGT gauges show | Display only. Set it a little above your warning so you can see overshoot |
Calibration tab
This tab only appears when Input Type is Analogue Voltage, because TCA boxes don't need one. Enter the voltage-to-temperature data supplied by your amplifier's manufacturer. The yellow Open icon loads a saved calibration file, and the blue Disk icon saves the one you've built so the other channels and future builds can reuse it.
Diagnostics tab
Each check is disabled by default. When Engine Protection is running, you can give each one a DTC severity so the ECU does something about it.
| Setting | Code | What it catches | Available with |
|---|---|---|---|
| Raw Min | P0545 | Signal voltage below your limit, a sign of a short or broken wire | Analogue Voltage only |
| Raw Max | P0546 | Signal voltage above your limit, also a wiring fault | Analogue Voltage only |
| Operating Max | P1321 | Exhaust temperature above your limit | Both input types |
Operating Max is the one that protects the engine. Start with a severity that warns the driver, confirm it isn't tripping on normal pulls, then decide whether it should step in harder, such as pulling boost or limiting power.
Troubleshooting
| Symptom | Usually |
|---|---|
| TCA channels don't appear in the input list | The TCA isn't enabled in Devices, or the wrong Box A/B is ticked |
| One cylinder reads far colder than the rest | Misfire or dead injector on that cylinder, or the probe isn't in the gas flow |
| Readings jump or read nonsense | Thermocouple wiring damaged or near an ignition lead |
| Analog EGT reads wrong at every temperature | Calibration doesn't match the amplifier |
FAQ
Should I run one probe or one per cylinder?
One probe on the collector or turbine inlet is enough for protection. For per-cylinder tuning, one per runner is the only way to see the spread between cylinders.
Can an EGT reading tell me my mixture?
Not by itself. EGT rises with both lean mixtures and retarded timing. Read it with a wideband, and our knock control setup, for the full picture.
