If your Mazda MX-5 smells like gas, you should treat it as though you have a fuel leak until you for sure there isn’t one. The smell of gas is typically going to be caused by a bad gas cap, evaporative emissions system, overfilling the gas tank, or an actual fuel leak. But there are other, less likely causes as well.
MX-5 Smells Like Gas: No Fuel Leak
Here are the most common things that would make your MX-5 smell like gas outside of a fuel leak itself, which is covered in the next sections
1. Gas Cap
The gas cap’s job is to keep the fuel vapor and fuel in the gas tank. It has a seal that can go bad over time. Once that happens, it’ll begin to let fuel vapor out and into the air. Since it’s behind the driver, you really shouldn’t smell the smell of gas unless you are going down the road.
2. Fuel Vapor Exposure
If you have just gassed up, you may have pulled somewhere where fuel was on the ground. If this is the case, it can make its way up into your MX-5’s cabin. When this happens, the problem slowly goes away and should not return. If it doesn’t seem to dissipate, it’s time to move on to the next potential problem.
If you are consistently gassing up and smelling gas after, you can rule this one out. There is one slight exception though. If you are the type of person that likes to squeeze in the last half gallon by making the pump click 5 times, know that your MX-5 was not meant to be fueled like that. You’ll smell gas until it is not longer overfilled.
3. Fuel Pressure Regulator
If the fuel pressure regulator has gone bad, it can let too much fuel into the fuel rails. When this happens it’ll throw off the air/fuel mixture. This causes your MX-5 to have a gas smell coming from the exhaust pipes and a noticeable smell of gas.
Replacing the fuel pressure regulator is the cure for this problem. Here’s a video on how to use a fuel pressure regulator with a pressure gauge, and here’s one that uses a diagnostic scanner to actually look at what’s going on in the engine.
You may also notice black smoke coming from the tailpipe.
Mazda MX-5 Smells Like Gas: Fuel Leak
It can be challenging to determine where the smell of gas is coming from in a vehicle. Gas dries fast, which adds to the problem. One of the best ways to determine if you have a fuel leak is to observe the fuel economy. Has it gotten a lot worse? That’s a tell tale sign that the fuel is going somewhere, but not the engine.
Here are places that fuel will commonly leak from:
1. Fuel Lines
If one of the fuel lines has been damaged, you should be able to find the leak by doing an inspection. Is there gas on the garage floor? That is a tell-tale sign of a fuel leak. If you do find gas, you should consider your Mazda MX-5 undrivable until you have it repaired. It could catch fire.
2. Gas Tank
A typical place where gas leaks form is the fuel filler neck. Specifically, where the neck meets the tank. There is a seal there that can go bad over time. Replacing it will solve the gas smell.
If a fuel injector is leaking, it will allow too much fuel to dump into the engine. Eventually it can fill the entire intake up and leak everywhere.
There are a lot of things that can cause you MX-5 to smell like gas. Even though it’s very likely that it’s a benign reason, always give the smell of gas the respect it deserves until you find the leak. If there is anything that you’d like to add, please leave a comment below. Good luck!