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gasoline leaking from catalytic converter/exhaust flange of 96 ES300

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Old 08-10-14, 03:09 PM   #1
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Default gasoline leaking from catalytic converter/exhaust flange of 96 ES300

Hi. Lately, I've been smelling fuel while driving only to notice that there was a stain from my tailpipe. I read that it could be simply water from combusted gasoline, but I discovered that it smells an awful lot like gasoline and stained a piece of paper like gasoline. I checked the undercarriage and saw a leak right where the front exhaust pipe flange meets the catalytic converter. While I'm sure that this leak will need to be addressed as well, the part that concerned me the most was that the leak was comprised of gasoline as well!

I took it to a shop to be examined and they suggested that it's related to the fuel pressure regulator. But, from what little I know, the fuel pressure regulator does not play a critical role in the conversion of gasoline as it is related to the movement of gasoline to the engine. I also noticed that every time I refuel, I lose that gasoline without so much as moving ten feet.

My guess is that it's tied to the ignition system and was wondering if there is a common solution for addressing what I just described like swapping out spark plugs. I went to Auto Zone to request a fluorescent dye to pour into my gas tank but they only have the dye available for the cooling system. I thought that it was a fuel line issue, but now am thinking that the problem lies in the part of my car that burns the fuel, because the fuel has at least reached the exhaust pipe, albeit in an uncombusted form.

Any help on this would be much appreciated!

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Old 08-10-14, 07:27 PM   #2
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one of your injectors is likely mal-functioning.

It may be that it's remaining open or semi open at all times. This will cause the engine to pump exhaust gases and fuel. This will mean that fuel is pooling in front of the cat. This would make your car a bomb, literally, waiting to go off. Which seems unlikely since you've been driving it a while now.

The engine should be running a bit poorly for this hypothesis to be correct.

The only other options I can think of are a fuel leak in the air assist part of the lower manifold, which has caused it to enter the intake.

The engine should be making less power, and the line air assist lines (either side of manifold, meeting in a plastic box above the thermostat) should be full of pressurised fuel when the engine is running.
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common , es300 , fuel , leaks , lexus

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