GDI Fuel Rail Pressure Too Low During Cranking

Description

The fuel rail pressure in the GDI system does not reach the minimum required pressure during engine cranking.

Symptoms

• Extended cranking time
• No start condition
• Rough start then smooths out
• Fuel rail pressure reads low on scan tool
• May start after multiple attempts

Common Causes

• Worn high-pressure fuel pump
• Fuel injector leaking back
• Rail pressure sensor error
• Low-pressure supply pump weak
• Fuel check valve leaking

Diagnostic Steps

1. Monitor rail pressure during cranking
2. Check low-pressure fuel supply
3. Test fuel injector leak-back
4. Inspect high-pressure pump cam follower
5. Measure cranking RPM

Repair Notes

{"Replace high-pressure fuel pump. Test fuel injectors for leak-back. Ensure low-pressure supply exceeds minimum feed pressure."}

Related Codes

Other Powertrain Codes

P3651 on Other Vehicles

Common Questions

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