Hello everybody.
1987 Mazda RX-7 FC S4 N/A, imported from the USA.

When the Fuel warning light, lights, does that mean that there are:
=> 5 liters (or 1.3 gallons) of fuel left on the fuel tank
=> 10 liters (or 2.64 gallons) of fuel left on the fuel tank
=> 15 liters (or 4 gallons) of fuel left on the fuel tank
=> other???

When I bought the car, it didn't came with the owner's manual along with it, so I have to ask...

 

According to my 1988 owner's manual, it's 11 liters (2.9 US gal).

 

I'll say about 2 gallons also.(about 10L)
My light and gauge work very well and the gauge still reads a notch or two when the warning light goes on.

 

Lucky! I've never seen a working fc low fuel light....as a matter of fact I've never seen a working light in a first gen miata either.

 

The lamp should be easy to replace, I guess. Mine takes about 10 seconds to light on after I turn the key.
Thank you for the answer, guys.

 

My warning light cluster is so screwed up that the low fuel light stays on all the time. I even tried re-soldering all the points inside. The clock still works intermittently, and the fuel light stays on constantly. I'm pretty sure it's non-salvageable because all the components inside are all rusted out.

 

I've got an S4 warning cluster if you want it...PM me.

 

The low fuel warning light is not particularly consistent from one FC to the next, and the sender is a frequent failure point. When I first bought mine my sender didn't work right, so the gauge got lower, lower, and lower, and I never got a low fuel light so I ran out of gas. I'm sure you could manually force the light circuit to power on to see if the bulb is still good, if it is then you probably have a bad sender (the mechanical level sensor in the tank). They're easy to swap out though, just don't strip the screws or drop anything in the tank and you'll be good to go.

 

I'm not sure what your saying there above. The light should not come on immediatley when the key is turned to ON. There should be a delay before it comes on after you turn the key to ON.

 

Yes, that's what I meant. I turn the key into the ON position (don't need to start the engine), and after like 10 seconds, the fuel light slowly fades in. It doesn't now because I've filled the fuel tank

 

The low fuel light and the fuel sender are seperate from each other. I wouldnt rely on either anymore.

Few full tank and trip resets to get an idea of your economy and then error on the safe side until you know your vehicle.

 

Yeah, I think they are both working correctly on my car, thought. But I will safely carry a 5 liter bottle with petrol in it in my car when I test that system (if it's working correctly or not).