So here is the problem, just got a 1979 RX-7 and just got it running after sitting for a long time.

compression is good (had a mazda tech check that)

fuel pressure is ok

filter is ok

oil was good but changed it anyway

the car starts right up and idles very nicly. Anyway when you rev the motor it doesnt wana rev very quickly and when you do rev it it backfires up through the carb a bit...

I have checked the cap and rotor and wires seem to be all ok, plugs are new

all vacuum hoses are intact and in the correct location. there is a sensor??? on the pass side of the carb that has one wire coming off of it, it screws into the carb itself, that wire is broken off inside the sensor .... What is that sensor for

also the fuel guage doesnt work and I put 10 gal of mid grade fuel in ..

let me know what you think

 

Its a rotary thing, some of us like them to backfire.

Check the timing...

 

OK...let me be the first to suggest a simple search. Normally, I hate it when people respond by saying "search", because I know how hard it is to find what you're looking for. But in this case I know it would have been easy to find a recent thread discussing this very topic, because I started the thread!

https://www.rx7club.com/1st-generation-specific-1979-1985-18/backfiring-problem-531873/

Anyway, welcome to the forum, and good luck!

Rich

 

no the car is not backfiring through the exhuast it is backfiring back up through the carb... makes a pop pop pop, whith the lid off the air filter you can see the flame come back up through..

strange I know

 

its a timming isue took me a while to figure it out but my car wouldnt stay idel just back fire heaps

 

Definately sounds like timing to me. That 'sensor' on the passenger side of the carb isn't a sensor at all, it's the float bowl vent solenoid. You should get that fixed as it can cause the carb floats to overfill and flood if it isn't working properly.

 

One more vote for timing. I don't know of anything else that will cause backfiring through the carb as long as you have good compression...

 

thanks, I got some new points and caps I am going to follow the procedure and set the timing I will get back to you when I am done