1st gen backfiring
 

I have a 1980 RX7 that I recently had the carburetor rebuilt on. I have it tuned to idle correctly but when you run through the gears at full throttle it backfires between shifts. It does this more so when it is cold. Any suggestions on fixing this issue?
THANKS!

sounds like your idle is a little on the lean side.. could also be some of the emissions components if they're still connected

I thought about stripping all the emissions stuff off. Does anyone know what part of the emissions system could cause this? Thanks in advance for the help.

the deceleration dashpot should prevent it, maybe not at high RPM though, i wouldn't worry too much.

not a good idea to thrash it while its cold tho. should go with 3.5krpm shifts until it warms up i think

lots of things can do it when it backfires it means that a lot of unburned fuel is ending up in a hot exaust pipe. First check your timing for accuracy, as well as check your carbon canister, your gas tank vent, and engine crankcase, are fed into it. If the Can is plugged it can force fuel back into the return line and it can both starve you of fuel(no tank vent)or flood your car at Idle. Also check to make sure you have good fuel pressure 3-4lbs..But, no more. also if you can check your lower fuel line from the fuel pump to carb i have found numerous little cone shaped filters stuck up the fuel lines just past the fuel pump heading to the Carb. ( the Cure) Remove line both ends and pull out or blow with compressed air. also use 2 filters one at the pump and one before the carb to filter fuel. also check your car for a damaged Intake Gasket most have broken the water o rings and damaged the Intake gasket this can cause low vacuumand a rough running Engine............................................ .................Goodluck FP

Do you have any leaks in the exhaust system? This seems to be the main cause for backfiring, as fresh air gets sucked in through the leak and ignites the unburnt fuel in the exhaust system.

Timing is another good option to consider.

Carb info: www.sterlingmetalworks.com

Stripping the carb down to a "Naked Nikki": https://www.rx7club.com//showthread.php?t=912089







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