What engine protection actually does
Most sensors on a Haltech Elite can raise a fault: oil pressure too low, fuel pressure dropping, coolant too hot, mixture going lean. Engine protection decides what the ECU does about it. For each fault condition on each sensor, you choose either no protection or one of three severity levels. When that fault trips, the ECU applies the level's settings, adding fuel, pulling timing, cutting boost and lowering the rev limit, and holds them until the level's Active Condition allows normal running again.
Think of the three levels as three different responses you design once and then assign to faults:
- Level 1: the mildest response, for things worth a warning and a little margin.
- Level 2: a firm response that takes most of the power away.
- Level 3: the most severe, for faults that will break parts if you keep driving.
Each level can be switched on or off by itself, and each carries its own values for the settings below.
The settings in each level
| Setting | What it does | Defaults (L1 / L2 / L3) | Our advice |
|---|---|---|---|
| Enable | Turns the level on or off | - | Enable every level you actually assign to a fault |
| Enrichment | Adds a percentage of fuel. Only shown when there is no Target Lambda table, for example with the Injection Time fuel method | 2.0 / 5.0 / 10.0 | Richer is safer for heat and detonation; keep the steps sensible |
| Target Lambda Enrichment | Subtracts from Target Lambda to run richer. Shown when a Target Lambda table exists (VE or MAF fuel methods, or O2 control on) | 0.2 / 0.5 / 1.0 | Enter it in the units your target table uses |
| Boost Correction | Percentage change to boost while protection is active. Needs boost control enabled | 0.0 / -50.0 / -100 | Pulling boost is the fastest way to take load off a turbo engine |
| Retard | Degrees of timing removed | 2.0 / 5.0 / 5.0 | Pairs well with enrichment to reduce knock risk |
| Rev Limit Type | Fuel cut or ignition cut for the protection limiter | Fuel Cut | Fuel cut is the gentler choice for exhaust and turbo |
| Rev Limit End | The rpm ceiling while protection is active | 10000 / 4500 / 2000 | Set Level 3 low enough to force the driver to back off |
| Active Condition | What it takes to return to normal | - | See below |
The rev limit here doesn't fight with your other limiters. The Elite always uses whichever limit is lowest at the moment, whether that's the main or auxiliary limiter, launch control or engine protection. Note that the Level 1 default of 10000 rpm effectively leaves the rev limit alone.
Active Condition: how protection ends
- Current and Past DTCs: protection stays on until someone clears the trouble code in ESP. Even a key cycle won't bring full power back. Use this for serious faults where you want the car looked at before it's driven hard again.
- Current DTCs only (Drive Cycle): protection lasts until the ECU powers down, and the engine runs normally on the next start. This suits minor faults that may just be a one-off.
Cylinder shutdown on high EGT
If you have an exhaust gas temperature sensor on every cylinder, the Cylinder Shutdown tab appears. It watches each cylinder independently and, when one runs too hot, kills both spark and fuel to that cylinder only.
- Enable: turns on per-cylinder shutdown. Once a cylinder is cut, it stays cut until the ECU is reset or power cycled.
- Max EGT: the temperature a cylinder must exceed to be shut down.
- Delay: how long the EGT has to stay above Max EGT before the cut happens. It stops a brief spike from shutting down a healthy cylinder.
Setting up the sensors is covered in our EGT sensor article, and you'll need a thermocouple amplifier such as the TCA8 for a V8.
How we set it up
We build the levels first, then work through each sensor and assign a level to its fault conditions. A typical approach:
- Level 1 for early warnings: slightly high coolant temperature, a small drop in fuel pressure. A little fuel and a little timing, no real power loss.
- Level 2 for faults that need the driver to back off now: fuel pressure well below target or a lean condition under boost. Cut boost hard and lower the rev limit.
- Level 3 for engine-killers: oil pressure low under load. Minimum boost, a very low rev limit and a Current and Past DTC reset so it can't be ignored.
Oil pressure is the one we set up on every build. Our oil pressure and engine protection guide walks through it. Then test each fault deliberately, for example by unplugging a sensor with the engine off, and confirm the right level shows in ESP.
These settings reduce damage once something has gone wrong. They can't make up for a lean map or bad fuel. Start conservative and check your logs for protection events after every session.
Troubleshooting
| Symptom | Usually |
|---|---|
| Car stuck in limp mode after restarting | That fault is set to Current and Past DTCs; clear the code in ESP |
| Protection never triggers | The level isn't enabled, or the sensor's fault isn't assigned a severity |
| Enrichment setting missing | You have a Target Lambda table, so use Target Lambda Enrichment instead |
| A cylinder stays dead after a hot pull | EGT cylinder shutdown tripped; power cycle the ECU and check why that cylinder ran hot |
FAQ
Which faults can trigger engine protection?
Any sensor error or fault condition that offers a severity option, commonly low oil pressure, low fuel pressure, high temperatures and lean AFR. The DTC index lists the codes.
Can I use boost correction without boost control?
No, it only appears when the boost control function is enabled.
