I picked up a 1986 na rx7 that had not ran in a long time and after sourcing parts I was able to get it started. All emissions have been removed from the car. It will start up just fine but when it comes to idling it will backfire like crazy and the only way it will stay alive is if I give it some throttle. Spark plugs are new, tps is new, bac valve is a used but working part, have tried putting in different eco. It would be appreciated if someone could point me in the right direction of where to start troubleshooting. Or if more information is needed I can provide.

 

welcome to the board.

is the gas in it old or fresh? what about the gas filter?

you are also likely going to be chasing vacuum leaks.

you'll probably need to get a copy of the FSM: Foxed.ca

 

If it is backfiring, change the mass airflow meter and the water temp sensor by the alternator.

If it is still backfiring it is sucking air from somewhere. ..

Alternatively, you can use the starting fluid check to see if it sucking air .. .I would spray the trailing fuel injector seals or the EGR valve area under the upper intake manifold and see if the RPM's get a rise

Backfiring is caused by excess air relative to fuel. . . . A bad MFM can fool the ECU into thinking the mix is right when it is not.

You can get a remfg MFM and new water temp sensor for around 150 bucks.. . .spend the money and see where it leads.

 

Mine acted like that, maf was the culprit. Backprobed the ecu and compare readings with fsm