There's a strong case smell coming from my cars interior. It's a 1999 Mazda mx-5 miata with a 2004 mazdaspeed miata engine. I've checked the engine to try and detect a smell, tried the exhaust, and the gas cap. I don't smell anything unless I open my car door, in which its coming from. Even when my car is off, it will smell, and (assuming) it will accumulate making a strong scent. I've checked my gas cap, and its good and working. I've checked the fuel injectors, but can't see or smell any gas. And the car doesn't leak anything. What is it? A fuel line leak? The evaporative emission lines? Fuel valve? The car also has a aftermarket ECU, and that was put on by the owner before me. He had gotten it on a dyno tune, but he says it will need to be tuned again. Will the tune help everything and that's just the problem?

 

Is your car running rich and have you any other problems you have noticed.

 

Have you checked that the pump is tight down and pipes are fully pushed onto pump as mine is located under rear seats in the 323f and pump was'nt tight up i had to get replacement screws.