The largest online repair guide library for every car

About us
Contact support
FAQ
Sign up
Sign in

2018 G90 5.0L experiencing intermittent power loss and P0087 code

0

Mike T. · rep 0 · May 25, 4:35 AM · 1 replies · solved · Question

Vehicle: 2018 Genesis G90 5.0L Ultimate

Hello fellow Genesis owners,

I own a 2018 Genesis G90 5.0L Ultimate with about 65,000 miles. Lately, I've been experiencing an intermittent but concerning loss of power, especially under acceleration. It feels like the engine is starving for fuel. The car also sometimes takes a bit longer to crank before starting.

Crucially, the check engine light has come on a few times, throwing a P0087 code: "Fuel Rail/System Pressure - Too Low". I've cleared it, and it comes back after a while. I'm worried about potential damage or being stranded. Has anyone dealt with this specific code or similar fuel delivery issues on their G90 5.0L? What was the fix?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 4:35 AM

0

ClearTheCode admin answer:

The P0087 code, "Fuel Rail/System Pressure - Too Low," on your 2018 Genesis G90 5.0L is a clear indicator of a problem within the fuel delivery system. Given the symptoms of intermittent power loss and long cranks, this code is directly pointing to the issue. The 5.0L GDI (Gasoline Direct Injection) engine relies on very precise and high fuel pressures.

Here are the primary components to investigate:

  1. Low-Pressure Fuel Pump (In-Tank): This pump is responsible for drawing fuel from the tank and sending it to the high-pressure fuel pump. If it's weak or failing, it won't supply adequate fuel to the high-pressure pump, resulting in overall low system pressure. Testing its output pressure and volume is a critical first step.
  2. High-Pressure Fuel Pump (HPFP): GDI engines utilize a mechanical high-pressure fuel pump, typically driven by the camshaft, to generate the extremely high pressures needed for direct injection. A failing HPFP is a common cause of P0087. These pumps can wear out or develop internal leaks.
  3. Fuel Pressure Sensor: There are usually sensors on both the low and high-pressure sides of the fuel system. A faulty fuel pressure sensor could be sending inaccurate readings to the Engine Control Unit (ECU), causing it to believe the pressure is low when it might not be, or vice-versa. However, your symptoms suggest an actual pressure issue.
  4. Clogged Fuel Filter: While less common on modern vehicles with 'lifetime' filters, a severely clogged in-tank fuel filter could restrict fuel flow. This would typically affect the low-pressure side.
  5. Fuel Pressure Regulator: This component controls the pressure in the fuel rail. A malfunctioning regulator could cause the pressure to drop too low.

When to See a Shop:

  • Diagnosing P0087 requires specialized tools to monitor fuel pressure in real-time on both the low and high-pressure sides of the system. This is not a DIY job for most owners due to the complexity and the high pressures involved in GDI systems (which can be dangerous). It's crucial to have a qualified Genesis technician perform a thorough diagnosis. They can accurately test both fuel pumps, the pressure sensors, and inspect the entire fuel delivery system. Driving with persistent low fuel pressure can lead to poor engine performance, potential stalling, and even damage to other engine components if the air-fuel mixture is consistently lean.
Menu

Help & account