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Autopapyrus · Honda Vezel 1.5 LEB Hybrid (2019)
https://autopapyrus.com/guides/honda/vezel/fuel-injection-system-diagnosis-and-repair/
Compiled automatically from service literature and owner experience. Specs are for the typical configuration — check them against your exact car before you start.

Honda Vezel 1.5 LEB Hybrid (2019): Fuel Injection System Diagnosis and Repair

The LEB engine in the hybrid Vezel (1.5 Atkinson-cycle with direct injection, paired with an electric motor) has a two-stage fuel system: a low-pressure pump in the tank and an HPFP on the cylinder head. Injection faults show up as unstable idle, misfires, hesitation when switching between electric and gasoline modes, and fuel pressure and misfire codes. First confirm which part of the system is faulty, and only then replace parts.

Difficulty: Hard Time: 2-4 hours (diagnosis), 3-6 hours (injector or high-pressure fuel pump replacement) Steps: 15 Tools: OBD-II scan tool with live data (fuel pressure, STFT/LTFT fuel trims, per-cylinder misfires), high-pressure gauge or a scan tool that reads the sensor, torque wrench, socket and box wrench set, fuel line disconnect tool, TORX sockets, multimeter, clean container for fuel, fire extinguisher, lint-free rags, plugs for open fuel lines

Part

  • 🔩 Determined by diagnosis. Typical candidates: direct injector (1 per cylinder) with seal kit and Teflon seals, high-pressure fuel pump (HPFP) driven by the camshaft, low-pressure fuel pump in the tank module, fuel filter, fuel pressure sensor, spark plugs. Select exact OE part numbers for your body and engine by VIN, since they differ between facelift versions

Step by step

15 steps
  1. Read the trouble codes with a scan tool and save the freeze-frame data. Pay attention to per-cylinder misfire codes, fuel pressure codes and fuel trim codes. Do not clear the codes before diagnosis.
  2. Note the conditions when the problem appears: cold or hot engine, under acceleration or at idle, when the gasoline engine starts from EV mode. This quickly separates fuel delivery problems from ignition problems and vacuum leaks.
  3. Rule out the simple causes first: condition of the spark plugs, ignition coils, air filter, intake hoses (check for vacuum leaks), and fuel level and quality. On direct injection engines, carbon buildup on the valves and injectors is a common cause, and worn spark plugs also cause misfires.
  4. Check the 12 V battery voltage and the grounds. In a hybrid, the auxiliary 12 V battery affects the pumps and the ECU, and a weak battery causes false codes.
  5. Check the low pressure, either from live data or with a gauge on the low-pressure line. If the pressure is low while the pump power supply is normal, look for the cause in the in-tank pump or the filter. To reach the pump, remove the rear seat and the access cover in the floor. Before working on the fuel system, relieve the residual pressure and disconnect the 12 V battery.
  6. Check the high pressure using the sensor data under operating conditions. A pressure drop or unstable pressure points to the HPFP, its regulator or the sensor. Do not measure pressure on the high-pressure line yourself without suitable equipment, because the pressure is very high.
  7. To diagnose the injectors, compare the fuel trims and misfires by cylinder. If a misfire is tied to one cylinder while the spark plug and coil are good, swap the coil and spark plug between cylinders. If the fault moves, the cause is ignition. If it stays, suspect the injector or compression. An accurate injector check requires a test bench (flow rate, spray pattern, leak-tightness).
  8. Before removing the injectors: let the engine cool, disconnect the negative battery terminal, remove the decorative cover, and remove the intake manifold or part of it as needed. Relieve the pressure in the fuel rail (burn off the remainder by running the engine with the fuel pump disabled, or follow the factory procedure). Prepare rags and open the lines without letting dirt into the passages.
  9. Carefully remove the high-pressure rail together with the injectors, loosening the fasteners evenly. Do not apply side force to the injectors. Close the open passages with plugs, and clean the carbon out of the injector bores in the cylinder head.
  10. Install new injector O-rings and Teflon seals. Lubricate them with a thin layer of clean engine oil (not fuel and not thick grease). Do not reuse old seals. On direct injection, they are the main source of leaks and of fuel getting into the oil.
  11. Install the rail with the injectors straight, without tilting, and tighten the fasteners evenly in several passes. I have not confirmed the tightening torques for the rail mounting, the high-pressure fittings and the HPFP on this model, so tighten strictly to the Honda specification for the LEB engine, not by feel. High-pressure fuel line fittings must be tightened precisely and only with a torque wrench.
  12. HPFP replacement (if the fault is confirmed): remove the cover and the fuel system drive, and follow the camshaft and lifter position per the factory procedure. Check the condition of the pump lifter and the cam. If they are worn, replacing the pump alone will not help.
  13. After assembly, turn the ignition on several times to build up low pressure, and check all connections for leaks and the smell of gasoline. Start the engine, warm it up to operating temperature, and inspect for leaks again. Read the codes and, if necessary, reset the fuel trim adaptations with the scan tool.
  14. Do a 15-20 minute road test in different driving modes, including starting the gasoline engine from EV mode. Check the fuel trims, the absence of misfires and the pressure stability. Inspect the connections again after 100-200 km.
  15. Also be aware of the recall campaign for the low-pressure fuel pump (the pump impeller may deform and cause the pump to stop, so the engine stalls or does not start). If the car shows these symptoms, check with a dealer whether your VIN falls under the campaign. The replacement is done free of charge.

Common mistakes and warnings

  • Working on a direct injection fuel system is dangerous: high fuel pressure, and a risk of fire and injury. Do not open high-pressure lines without relieving the pressure, work away from sources of sparks, and use safety glasses and gloves. The hybrid drive has a high-voltage system. You do not need to touch it for fuel system work, and you must not disconnect the high-voltage orange cables. If you have no experience repairing direct injection systems, leave the job to a repair shop and have the system tested on a bench. An assembly error can cause a fuel leak and a fire.