Fuel Pressure Sensor¶
Monitors fuel pressure so the ECU can correct injector flow and decide when closed-loop can be trusted.
What it is¶
The fuel pressure sensor reads the pressure in the fuel rail feeding the injectors. Because injector flow depends on the pressure across them, the ECU needs this reading to know how much fuel a given pulse width actually delivers.
Why it matters¶
Two jobs:
- Injector flow correction — since flow scales with the square root of pressure, the ECU uses the measured pressure to keep its pulse-width math honest as pressure varies. Below 20 % of target pressure no fuel is delivered at all.
- Gating closed-loop — if pressure drops below 70 % of target,
closed-loop trim is disabled (badge
OPEN (FAULT)). The ECU won't try to fuel-correct around a hardware fault, and the resulting lean condition is a pressure problem, not a tuning one.
How to tune it¶
It's a monitor, not a setting. Use it diagnostically: a lean condition with injectors not maxed, plus a pressure reading below target, points squarely at the fuel system rather than the tables.
Watch out
Don't re-tune fuel tables to mask a pressure shortfall. If the sensor shows pressure sagging under load, fix the supply — tables tuned around low pressure will be wrong once it's restored.
In the game¶
The FUEL PRESSURE bar in the left readouts shows the pressure in your chosen pressure unit.
Watch it hold steady under high demand.