How to Check if Sometimes Engine Hard Starting?

This case probably intermittent engine hard starting.

How to Check if Sometimes Engine Hard Starting?

Model: Hyundai Santa Fe (SM)

Year Model: 2004

Fuel: Diesel

Displacement: 2000cc

T/A : Auto

Subject: Intermittent Hard Starting = Fuel Filter

1) Condition:

1. Intermittent hard starting and hesitation occur when initial engine starting
2. Starting is possible after cranking for 2~3 times.
3. After starting, severe engine hesitation happens..

2) Cause:

1. Faulty check valve in the fuel filter.

3) Diagnosis

1. Scan tool check
   = No trouble found
2. Current data shows abnormal fuel pressure during starting.
3. Check the high pressure line – lower than normal pressure.
   
   Specification : Max 1,350~1,500 bar
   
4. Check the low pressure line – Normal
   = Tips for pressure test : Connect the rail pressure sensor with fuel line from high pressure pump.
5. Check the high pressure pump = Normal.
6. Check the pressure regulator in the fuel filter
   = The valve is stuck.
   = After replacing the fuel filter ( pressure regulator ), the engine operating normally.
7. The arrow high sign
   = Green: fuel return line
   =  Red : High pressure pump line.
   = Blue : Low pressure pump line.

4) Repair Guides

1. Replace the fuel filter assembly including check valve.

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