I started smelling fuel inside my 99 AE. It continued to get worse and the CEL came on with a P0455 code. I started by visually inspecting all the vacuum lines. I pulled the CDCV from under the passenger side rear and tested it to no avail. Then I pulled the Purge Solenoid Valve from the engine bay and tested it to no avail.
Finally, I realized that fuel smell inside the car must be coming from the top of the tank. So I pulled the rear carpet and panel to check. I found no problems with hoses, but could tell the fuel pump had been replaced. I found the mounting screws were all too loose to seal the pump cover to the tank. Once they were tightened there has been no more smell and no P0455 codes!
My 2000 Evo Miata has thrown a P0455 code since I finished restoration. I have just been resetting the code and hoping it would clear itself. Finally, I got tired of having to reset the code, so I put her on the lift to start tracking down the problem.
I found this on http://forum.miata.net/vb/showthread.php?t=209931 and planned to start under the car and work my way to the engine bay and then to the top of the fuel tank. I immediately noticed this at the charcoal canister under the passenger’s side.
This is a close up of the vacuum tubing. It has been broken and also chewed by a rodent. I cannot believe I did not find this when I replaced the fuel filter during restoration. Maybe it happened after?
This is my temporary repair until I can get the correct hose.
Hopefully, no more P0455 on the Evo!