I have an 85 with a 12a no mods and everytime i turn it off it backfires... Im not talking about a little "poof" I am talking about sounds like I am standing at the back of my car with a 12 gage. It also shoots a 3 inch flame from the tail pipe when it does.

I have tried to adjust the carb and it still does..... Anyones help would be helpful.


Thanks

 

It may also help knowing i am not running a cat on my exaust.

 

it could be as simple as an exhaust leak. i had a small hole in my exhaust and every time i let off the thottle above 3k it sounded like a shot gun and shot a flame. i patched the hole with JB weld and it fixed the problem

 

It dont happend when i take it to high rpms just when i turn it off..

Whats th best way to find in exhaust leak?

 

mine did this when i had weak spark plugs, and a small vacuum leak. some of the unburnt fuel would find its way to the exhaust and the temperature in there would ignite it. at the time i had headers straightpiped to a ebay muffler so it was VERY loud.

specially when you park on main street in front of the police department....never seen so many cops running outside with gun in hand.

 

my 1st gen gsl does this everytime i turn i off aswell but not as loud

 

https://www.rx7club.com/search.php?searchid=8550065

 

Facing the fire wall on your carb. There is like this valve thing that kind of looks like a pv valve. If removed or stuck it will back fire like that.

 

mine did it but it was my air pump (79 SA) but once i removed it no more backfires....which means no more fun at school zones and under bridges

 

Rx7's do run a little rich... are you sure you are adjusting your carb correctly? The 85 has different adjustment screws than other models. If you've got a haynes manual check the adjustment for the 85 is in chapter 13 I believe.(It's one of the last chapters) It might sound like a dumb mistake but I've seen plenty of people on the forums who were adjusting the wrong screw thinking it was the same set up as older models.