_Andrew_

I have a 2001 Jeep Cherokee Sport 4.0L and have been chasing the P0455 large evap leak for months now. Here's a list of everything I've tried so far:

- Replaced the gas cap twice
- Replaced all rusty evap lines going to and from the charcoal canister and the fuel tank
- Replaced the evap purge solenoid
- Replaced various rubber fittings in the engine bay
- Replaced the leak detection pump
- Dropped the fuel tank and visually checked the fuel pump, hoses and filler neck
- Replaced a cracked rubber fitting under the driver's side door (which was a pin hole and probably would account for a small evap leak)

I took it to a shop to get a cheap smoke test ($50) hoping they could tell me where the leak was. They said that the leak might be coming from an old fuel injector o-ring so I replaced the fuel injectors and o-rings (an upgrade I was already planning on doing) and checked to make sure the o-rings where tight and not leaking by pressurizing the system with an air compressor and spraying soapy water around the injector's bases. And I still have the P0455 Large EVAP Leak and don't know what to do next. I'm thinking about trying to replace the fuel pump gasket, but I feel like if the was a leak there it would be a small leak. I don't really know though.

I also tried cleaning electrical grounds and took apart the throttle body and cleaned everything the best I can. If anyone has any suggestions it would be greatly appreciated!

wakeskate

Try running a small amount of air through your system (literally 1 psi) check this link. Should hear hissing at the source of your problem. Check the link: