I bought a 2002 Jeep Grand Cherokee with the 4.7 as a project that I've been tinkering with. Like many others have experienced, it keeps tripping the check engine light with an EVAP leak code. I have replaced the EVAP Canister and Purge Solenoid (from a salvage yard) with no change. I did have a mechanic run a smoke test and he could find no visible signs of a leak.
One weird thing is that while the Jeep is running, pressure builds up in the gas tank and if I remove the gas cap (while running), it will quickly release the pressure and the engine will die. It is then difficult to add fuel to the tank, almost like there is a vapor lock. At this point the Jeep is then very difficult to start and I have to crank for a while before it will fire. If I remove the gas cap very slowly (while the engine is running) to release the pressure, it will not stall and I have no difficulty pumping gas into the tank. If I shut off the engine before removing the cap, no pressure is released and pumping gas into the tank is difficult.
Not really sure what's going on here. Is the Purge Solenoid still bad? Any ideas? Thanks.
One weird thing is that while the Jeep is running, pressure builds up in the gas tank and if I remove the gas cap (while running), it will quickly release the pressure and the engine will die. It is then difficult to add fuel to the tank, almost like there is a vapor lock. At this point the Jeep is then very difficult to start and I have to crank for a while before it will fire. If I remove the gas cap very slowly (while the engine is running) to release the pressure, it will not stall and I have no difficulty pumping gas into the tank. If I shut off the engine before removing the cap, no pressure is released and pumping gas into the tank is difficult.
Not really sure what's going on here. Is the Purge Solenoid still bad? Any ideas? Thanks.
