What is the cause of engine rough idling and how to check it.

The is one of engine problem occurs on your car.

What is the cause of engine rough idling and how to check it?

Model : Hyundai Santa Fe (SM)

Year Model : 2002

Fuel : Gasoline

Displacement: 2000cc

Subject : Engine rough idling – Injector.

1) Condition

1. Engine RPM becomes rough and vibration occurs at idle speed.
2. Poor engine acceleration during driving.

2) Cause

1. Malfunction of injector ( Cylinder # 3).

3) Diagnosis

1. Scan tool check
   = No diagnosis trouble code.
2. Check the high and low pressure line – Normal condition.
3. Check the amount of returned injection fuel.
   = Lots of returned fuel in the line # 3 injector.
   = The returned amount of fuel in the # 3 injector is much more than other cylinder.
   = Normal amount of returned fuel for 3 minutes in warm engine is approximately 18~20 cc.

4) Repair Guides

1. Replace the # 3 injector assembly.

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