- I'm getting barely 200 miles a tank (~15 gallons)
- My eyes burn if I stand within 5 feet of my muffler

The only mods I have are intake and header and exhaust (cat-less). All emissions in place.

 

Also, the car idles rough with a misfire. Almost sounds like a baby bridgeport or something. Turning the Idle Mixture Adjust screw to richer smoothens it out some, but then it's just running richer. I'm on less than 2,000 mile new spark plugs and new cap and rotor and wires. I've checked my vacuum lines thoroughly for leaks or breakages... no such thing as my lines are still soft and very much pliable.

I'm desperate for answers!!

 

check your oxygen sensor. when those go the car can go crazy rich.

 

Only at cruise and closed loop mode. The O2 sensors makes little difference on mileage. If it is running that rich at idle, look into floats and seats. If you have an aftermarket, (non-stock), fuel pump, check your fuel pressure. Try running some fuel injection/carb cleaner in the tank and shoot a can of it through the carb with the engine running. Check spark plugs and plug wires too.

 

^^ But it's a GSL-SE?

 

I am having the same problem. Last time i filled up i had avg. a whopping 13.7 mpg. Have you adjusted the TPS? I did this yesterday and not sure if has affected anything yet, but i will let you know. Good luck

 

Coolant temp sensor.... Car can't tell when its warmed up, so it keeps running rich.

 

The common knowledge on the 1st gen mailing list is that the things to check are the TPS and the O2 sensor. Run through David Lane's article on GSL-SE idle problems and that will probably fix 90% of what's wrong. Felix Miata was sceptical about changing out his O2 sensor until he actually did so with another one of his GSL-SE's. Reported mileage went from 16-17mpg to 24mpg. In the FAQ for this very section of this very forum is a question asking "My GSL-SE has idle and surging problems, how can I fix it?" Run through that and I'm willing to bet most of your problems get solved.

https://www.rx7club.com/1st-generation-specific-1979-1985-18/1st-gen-rx-7-faq-page-237777/

 

Does the removal of the coolant temp sensor involve removing the alternator and water pump? The Chilton's has little info on the temp sensor.

I replaced my O2 sensor last week and it seemed to do very little to my idle. Maybe it will help on highway miles, but around town nothing changed.

My next step is to check for proper operation of the BACV.

 

?

i have never had an oxygen sensor and i get approx. 24mpg

 

Sorry. I had been up all night working on a Camry and assumed carb. The 2nd gen guys find that the O2 sensors affects fuel mileage very little. For FI look at the TPS, BAC, and the fuel injectors. If the injectors have never been serviced, it will certainly help.

If the temp sensor on the back of the wp housing goes bad, it defaults to something like 72*. The other sensor the ecu reads is the iat, which is located under the bac and measures intake air temperature. It too has a default value if non-op.

If you are getting 13 mpg on the highway, I think there would be other issues, even if the wp temp sensor and the iat are non-op.

What do your spark plugs look like?

 

I also get that kind of gas mileage sometimes. Ofcourse it depends how I drive. If I take it easy, the gas mileage is much better than when I drive like speed racer.