fuel milage for 13b injection
 

well i just got me a 88' Rx7 last week and this thing is sucking gas like no tomorrow. i checked the mpg on it and its around 16mpg. not good, i bought this car thinking it would get better then that! my vw fox i had last for a car got about 20mpg runing like crap with 310,000ml on it. so whats up? is there some tuning i need to do, or is this correct?

If you just got the car and don't know it's previous owner or it's history, then yes there is some tuning work you need to do.
- Change plugs and plug wires; for plugs use NKG's recommended for leadings and trailings; for plug wires I would recommend 8 or 8.5 mm
- Change the fuel filter...located bolted to the firewall under the oil filter
- Change the oil and oil filter. Use a high quality oil, most on this forum recommend Castrol GTX in either 20W-50 or 10W-30. Use a good filter, not the elcheapos.
- Set the engine's timing to spec..or maybe a bit advanced.
- Set the TPS according to spec. There are several methods for setting the TPS. Read up and use any of them. Verify the setting by using a different one. I set by resistance and verify by twin light.
- Set the idle speed
- Check the air filter. If it is foul and filthy it will definately decrease mileage. For future reference, you will probably want to take out the stock air filter box and replace it with a cone filter.

There are copies of the Factory Service Manuals in the 2nd Gen FAQ section. Read up on your car in the "Fuel" section. Do your homework. Rotaries are a lot different from piston bangers. Most of what you will have questions on have already been asked and answered on this forum. Use the search function and read up before you ask again. This will help you to avoid getting seriously flamed.

Gas mileage around town seriously stopping and going might be as bad as 16. Open road highway should be in the low to mid 20's.

Some more thoughts on getting better mileage out of an RX-7....
- Change the oil in your transmission and rear end. Replace with a good synthetic gear lube like Neo, Redline, Royal Purple.
- Dirty injectors will rob mileage. Have them professionally cleaned and balanced. Gonna cost you around $100 for this though. Unless you can find an injector shop nearby
- Clogged catalytic converters will affect mileage.
- For open road travel a bad O2 sensor will affect mileage

Your car is an S4. Checking engine error codes is difficult, but you might want to look into having your engine error codes dumped to see if there is anything else going on that needs attention.

wow, never thought i would get that kind of help! the motor in the car has about 50,000 miles on it and the body has 154,000 on it. the last owner replaced the motor at about 130,000 miles. not shure why never asked him. but yea i will check that stuff out, ive been to busy with work and school to take it in the garage and check the motor out besides a oil change with castrol gtx 10w-30 and a carquest oil filter. but that what i was going to do, but no point if that mpg's where correct. so thanks again for the help.

Get rid of the car.
The engine will not get better gas mileage unless you're going to always drive it on the freeway and never hit the brakes.
The cars were never known to get "great" gas mileage and that's one of it's primary downfalls.

We don't own these cars to get good gas mileage.


-Ted

I get 300 miles a tank in my 87 turboII thats mostly all highway though with no boost, I think I am missing out on 80 more miles to a tank if the car was perfect, its got 101,000 on original engine

You might want to consider and aftermarket ignition, like the Jacobs FC1000. These have been said to give you 2 or 3 mpg and a bit of power. Should pay for itself in time...

Just do a 60k tune up and drive the dang car. It's a sports car, you're not suppose to worry about little deails like gas mileage. You'll soon get over the fact that you have to stop for gas (and oil) more often 'cause your having so much fun....

Check your plugs, change the oil, and make sure you dont have an exhaust leak.

thanks for all the input. ive had the car for over a month and im lovin every minute of it. ive come to the fact that yes they dont get the best gas milage and stoping for oil and gas is a comin ritual every week for me now. ive replaced the plugs changed the oil and it seemed to help a little. as far as an exhuast leek i think the colecter gasket needs to be replaced i get a nice poping back fire from that area when i let off the throttle at high revs. next is going to be the ignition box from jacobs, it looks like it should help alot.