Hi,

I have a 92 prelude with a 95 JDM H22a engine. It has a hi flow cat back with an apex i exhuast and dc headers. The problem is the very strong smell of gas from the exhaust (Absolutely no smell on the inside). Also when I shut it down there is a loud hiss from the exhaust as well. Please help. Thanks

 

you have any cel codes? (check engine light)

 

I have had the battery disconnected for a while. I'am guessing the ecu reset already. When I connect it back up and let it idle (rev it abit) for a bit and shut it off... will it be able to give me a cel code right away when I jump it?

 

Im sure it will, depens if your ecu sense something wroung right away. Make sure the leak is not from under the hood because you dont want to burn down your car. Did you do anything to your car latly? (motor swap or something?)

 

The car has the mods listed in the first post but those were done a long time ago. Nothing was recently done expect the replacement of the dizzy, spark plugs and wires.The oil pan was leaking previously but it stopped. The smell has been there for months and so I don't drive it often.

 

So you dont have any cel? Is your distrubeder standing in the middel? How dose your car idel? Some times(rare) a fuel injecter gets stuck open causing a cylender to flood. thats all i can think of.

 

It idles fine but Its unusually quiet.. sometimes the rpm bounces. But if that cynlinder floods won't it be undrivable?

 

And the smell of gas is definitely emanating from the exhaust flow and not just generally from the rear of the car (obviously the fuel tank, pump, and filler neck are all towards the back of the car too)?

So, either too much fuel, fuel isn't igniting, or fuel isn't burning well.

If it was an injector problem it could have a uneven idle or a miss or power lose at high rpm and wide open throttle. Same would be true for ignition problem.

But if it was running rich or having an incomplete burn the ECU should catch that.

Take the plugs out and see how they all look and compare to each other.

Compression test is always good info to know too.

 

It sounds like two possibilities. 1. A plugged cat or muffler causing a large backpressure. If this is a problem, then you will have issues like rapidly decreasing power as RPM increases. 2. How is mileage? If you get below 20MPG, replace the Oxygen sensor (just ahead of the Catalyst). If the oxy sensor is bad, you will get terrible mileage (all the way down to 12-15 in mixed driving) without really running badly.... But it will has a very strong exhaust smell due to excessive CO.

A final thought - if there is excessive fuel in the exhaust, it may get enough air when you turn off the engine to combust - causing the hissing. A 92 model should get around 23-25MPG highway, as I recall. My 94 with 2.3L was getting 13 highway and had a strong odor. Replaced O2 sensor and now I get 21-22MPG and exhaust smell is normal again.

 

duanes, I thanks so much for your input. I think I should try what you said first then check my valve lash. I am looking into the EVAP System in the service manual is states that the EVAP system is: "designed to minimize the amount of fuel vapor escaping to the atmosphere". Maybe there's a problem there? Also my exhuast system is an Apex'i World Sport 2 (WS2) - It's a "Cat-Back exhaust" I believe. The previous owner installed it. What's the difference between this cat-back and a regular exhaust? Can I still install a new cataylic converter with the apex'i system that I have?

 

yes u can install a new catalytic converter with the World sport..apexi aswell as some other exhaust systems allow you to utilize factory catalytic converters, other wise get ur local muffler shop to weld up a new cat. converter..

 

i had the same problem when i was running type-R headers and 2.25' straight pipe and it was smelling bad like fule was burning so i put a high flow cat from summit racing and what do you know the smell went away .

 

The evap system is there to trap fuel as it evaporates off of the fuel tank. When the engine is running, the vapors are sucked into the manifold and burned. Normally, the amount of vapor is very low compared to the intake air volume and makes a barely noticeable difference.