VW Passat B7 1.4tsi engine malfunction

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2012 VW PASSAT B7 1.4tsi

The engine was malfunctioning.I came into the store with the check engine light on.

・The engine suddenly stopped starting after driving for a long distance.

・Engine is difficult to start

It seems that these symptoms are occurring.

I'll diagnose it right away.

The main failure memory is

・The mixture is too rich (gasoline is too rich compared to the air)

・Pressure drop in fuel system


Measure fuel pressure.

The needle is jiggling and unstable. strange

leave it aside for now

Remove the plug and check

Pitch black.

It can be seen that the combustion is quite intense.

Lambda sensor (O2s sensor) value

The λ (lambda) value is displayed as 0.7.

λ=1 ideal combustion condition

λ> 1 Excess air amount (lean mixture)

λ< 1 Insufficient air amount (rich mixture)

Therefore, the situation is quite rich in gasoline.

It seems that there is no blockage in the inhalation route.

Is it caused by dripping from the injector (fuel injection device)? ?

Insert the HC tester into the plug hole and measure the concentration.

The numbers will go up.

There is HC reaction in all four cylinders.

Something is wrong.

When I opened the oil filler cap, it smelled like gasoline.

Is the oil mixed with gasoline?

Insert the HC tester into the oil level gauge

It is confirmed that the oil is mixed with gasoline.

It is unlikely that all four injectors are leaking gasoline.

This is the only possibility.

high pressure fuel pump

When I removed it and checked it, I found that gasoline was leaking into the engine.

High pressure pump replacement

Decided to replace the engine oil/filter that has been diluted with gasoline!

The defective pump on the right side that was removed has a shortened tip.

Fuel may have leaked out due to damage exceeding the movable range.

Replacement of the high pressure fuel pump stabilized fuel pressure.

Gasoline was flowing into the engine.

This is why the needle was not stable.

The lambda value has also improved to around 1, which is almost ideal.

If you look into failure cases overseas, it seems to be a fairly common failure with VW.

I don't want it to be that common!

The amount of oil diluted with gasoline had increased slightly and it was in a shabby state.

It is a relief that there were no problems with the engine due to poor lubrication.

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