Fuel Smell through Air Con

[Cloudxiii]

 twinturboboy said:

Hi guys my E-tune 2001 Legacy has had a bit of a fuel smell through the air con in the cold mornings or just on startup when the engine is cold for a while now - and I have done a bit of searching and found that the problem seems to be with the fuel hoses under the Manifold?

I have also noticed that the fuel consumtion seems to be not very good for an E-tune - Im only getting about 380kms or less on a tank

Can people confirm that I will have to take the manifold off and how long a job this is?

Cheers

I have a B4 Legacy 2001 BE5 that has the same problem with a fuel smell coming through the air vents. I have had a mechanic replace the 3 hoses under the manifold (and yes it needs to come off), all clamps replaced and tightened as much as they can. While the fuel smell is still there it is not as bad as it was but then again we are coming back into winter so it might get worse again. I really wish that someone knew the exact cause as it\'s driving me insane. My next step would be to replace the entire fuel rail but dont have that kind of money to achieve this. Does anyone have any suggestions?

[Rosssub]

Change your Cabin Air Filters. They will be causing the smell since leak fix.

[B4_685]

My 2001 BE5 does the same in cold weather. Once warm, smell goes away. When I get time, will pull manifold to have a look

B4_685 via Tapatalk HD

[Cloudxiii]

 Rosssub said:

Change your Cabin Air Filters. They will be causing the smell since leak fix.

I had my air filters cleaned and replaced since and just recently had my air con treated. The car smelt great after I got back in it but the next day, the fuel smell was there as it was warming up. It might be worth mentioning that at the same time i got the hoses and clamps replaced, the fuel filter, pump and pump housing was replaced.

[Rosssub]

Could you feed 12v straight to the Fuel Pump to crank the Pressure up, making small leaks more visible. ???

Or feed Compressed Air straight into the Fuel Tank for the same reason??? Which would also test the Fuel Return Line. ???

Or could it be Blow By Gasses your smelling, through a Split/Leaking PCV hose at the Block Breather. Disappearing as the Engine Warms/Things expand and Blow By Flow drops. ???

[Cloudxiii]

could you please elaborate on your last paragraph. Nor really sure what you mean by blow by gasses and blow by flow.

[Rosssub]

Crankcase Ventilation/PCV (Positive Crankcase Ventilation)/Engine Breathers.

Is how the Engine gets rid of, or re-uses un-burnt Combustion Gasses from the Crank Case.

Your Piston Rings have Gaps in them, a small amount of Combustion Gasses from the Cylinders, escape through these small Gaps into the bottom of the Engine/Crank Case/Block. These un-burnt Gasses are referred to as Engine Blow By.

Subaru\'s/Boxer Engine have Head Breathers as Well, these \'T\' together over the Intake Manifold and feed back into the Intake also. Normally near Alternator or closer to AFM.

Emission laws overseas require these un-burnt Gasses, to be recycled back through the Engine. Which is why they go back into the Intake. In NZ they can be Vented (currently) through a Filter or Breather. (see filter/breather type Catch Cans) But I\'m pretty sure these tight emission laws will very soon come into effect here as well.

When your engines cold, mechanical parts inside like Piston Rings etc haven\'t expanded yet. So your Piston Ring Gaps are slightly larger, your Bores/Pistons slightly looser. So there is more Engine Blow By when cold.

The Block Breather Fitting on the EJ20 is crap. I\'ve seen (read about) 4 broken in the last 3 months. The short 20mm hose perishes, splits and the Plastic Fitting Breaks (brittle/heat/age).

This would cause the Engines Blow By Gasses to be leaking, rear drivers corner of the Engine Bay.

When cold-more Blow By-More noticeable Petrol Smell. Just a hunch