VW Tiguan Engine Vibration When Accelerating with EPC &OBD Light on

A customer drove his Tiguan to my garage and told our technicians that the engine shaking when accelerating and EPC,OBD warning light on,then engine will be smooth when engine up to 2000r/min.Here share the progress of how to repair VW Tiguan engine vibration when accerating.

 

Information:

Vehicle model:  VW Tiguan 1.8Tsi SUV

Year:          2010

Mileage:       3,50 thousands miles

 

Trouble Testing:

Technicians found below trouble:

• Instrument cluster EPC and OBD warning light on after starting engine.
• The engine worked normally at idle but shaking when you press the gas pedal to accelerate.
• The engine run smoothly when engine speed up to 2000r/min.

 

Our technicians suspected that it may caused by below reason:

• Misfire of engine
• Lacking of air flow value or fuel-injection quantity
• Uneven pressure of engine cylinders

 

Trouble Diagnosis:

Our technicians connected the vas5052 to vehicle and read out below trouble codes:

P0300:Random Cylinder Misfire,it means that cylinder(s) is misfiring or is randomly misfiring.

P0304:Cylinder 4 Misfire,it means that cylinder 4 is misfiring or is randomly misfiring.

P130A:Cylinder Disabling,it means that engine comtrol module(ECM) has detected an excessive misfiring and that ECM has switched fuel injector(s) ’OFF’ to prevent engine and exhaust catalyst damage.

 

Technicians suspected the it may the poor combustion of 4 cylinder result engine vibrating.So technicians removed the spark plug injector,then found the spark plug fouling seriously of 4 cylinder.Technician clean the injector and repalced a new spark plug,but the trobule still existed.Exchanged the engine ignition coils between 3 cylinder and 4 cylinder,then tested the engine and found the trouble codes read out by diagnonstic tool was still indicated 4 cylinder misfireds.

Note:More about how to judge spark plug to read:

Read your spark plug color-spark plug reading chart

 

Turned off the fuel injecting and ignition,and used the cylinder presure gauge to detect the pressure of each cylinder.Found the pressure of 4 cylinder was lower than others(low about 1 bar) .With the customer’s agreement,our technician dismantle the cylinders to check the leakproofness and found poor leakproofness on 4 cylinder intake valve and valve retainer poor contacting.

 

Trouble Solution:

1.Clean the carbon deposit of cylinder shell

2.Replace 4 cylinder intake valve

3.Fix the valve retainer

 

Then installed them back,the trobule disappeared.