Hello, I just picked up an '87 FC N/A and it is running really rich. I can smell fuel every time I start the car and sometimes it will puff a little gray smoke out of my exhaust. It will backfire decelerating at higher RPM's and I can hear subtle pops as the RPM's drop. I have been trying to read about how to adjust it, my Chiltons manual doesn't say much and I read somewhere online that it is ECU controlled. The best I can come up with is this link http://mazdarx7.iougs.com/deceleration.shtml

Can someone shed some light on this for me?

P.S. I am new to RX7's and rotory motors.

 

Perform a full tuneup.

 

Could you be a little more specific? Such as clean the injectors, replace the filter etc? Im not sure what you mean.

 

Full tune up should include a lot of little things
filters - all of them
fluids - all of them
plugs/wires
change out all of the wearables.

This should cure most of the problem.
Once that is all done, you can focus on other more specific issues.

 

Besides changing the spark plugs, I would test the TPS to be sure it has smooth resistance changes and proper resting valves. It will affect how smooth the RPMs drop off after you let off the gas.

 

This only applies to backfiring: The ACV has a Anti Afterburn feature to prevent backfiring. So if you don't have a ACV, install one.

Timing also matters. Set the timing using a timing light with a HOT engine and its rpms well under 1100rpm.

Lack of a working catalytic converter will give you heavy exhaust fumes that some consider a *gas* smell.

 

You'll find links to the Factory Service Manual in the FAQ.