hey guys,

As the title says, my car backfires about ten seconds after turing it off. While I don't mind, it scares my girlfriend and annoys my mom. She's worried about the neighbors... Do you guys know what's causing it? Any similar problems/solutions?

 

need to check if you have a leak close to your header, or exhaust manifold, sometimes cool air goes in and backfire like that;

 

i'm pretty sure the gasket is ok, is there anything else?

 

mine does it as well.. it only really does this after i have been driving on the highway or doing some sprited driving and don't cool it down before i shut down... i have 2.5 in free flowing pipes, i figured it was the colder ambiant air rushing into the tail pipe after shuting it off that causes this...

 

hmmm...interesting...

 

i get it with my RB headers, resinator, and pp muffler.

 

Used to get it all the time with the old 79. Sometimes I would blip the gas and shut it off just to get it louder

Then one day... it exploded

 

my 85 will do that when i rev it a little when i shut it off. i love scaring people in parking decks with it

 

Mine only does it when it's still in its warm-up cycle with the choke on and I kill the engine from about 3,000rpm...

Does it do that every time you shut the car off? how's your idle? having any other carb or mixture issues?

Jon

 

I had the same problem with my 79. It was a bad ignition switch. It was worn out and whenever I hit a bad bump and the (heavy) key ring would jump around, it would momentarily shut of the ignition and I would get a gunshot.

It also happened whenever I shut off the ignition. Replacing the key switch solved the problem for me.

 

Happens all the time.
The key shuts off the spark,but not the carb(since its mechanical).
As the engine winds down,it pulls in fuel and spits it,unburned, into the exhaust which is very hot on a rotary.That wasted fuel will explode,often violently when it hits the exhaust system.The faster you rev the engine,the longer it will take to wind down and the more fuel it will dump into the exhaust.My old engines used to "poot" every time I shut down,and they would lay out a shotgun blast if I revved it first.
EFI engines wont do it since the key kills the sparkplugs and the injectors when you turn it off.

 

well thats normal just let it idel a few mins before you turn it off so the exhaust can cool and it wont be as bad

 

Check the idle. If the throttle plate is slightly open at all, there will be residual fuel that will feed, then you get the BOOM!

 

for the frist week or so i had my car it flooded on me a few times ect, i read on a web site how to stop it from flooding when you shut the car off . bring the car up to 3 grand hold for 10 secs then shut the car off and press the gas in for 5 then release. the frist time i tried it was so funny. my buddy pulled my car up his drive way so we would have move light for me to weld the floor in our 1984 rs turbo capri. well he stalled my car out doing so. a few hours go by and i go to leave car wouldnt start. blah blah blah i got the car started needed to work the gas pedal just so right. any way i needed to get some smokes so i went to little peach to get some. befor i shut my car off i was like f##k i dont want to stall it out hear. well i rember that thing i read on the internet bring it to 3k ect. i did it and as soon as i took my foot of the gas pedal bang. i was looking out my left widow and some dudes standing by a truck the hit the ground a bunch of dudes came out from the store and was like who got shot ect ect . mean while iam in my car lol all most to tears. i get home and do the same thing cause. 2 days go by my the lady who lives next door asked me if i shot a gun off ect. i told her it was my car she was on the can smokeing a butt droped it and burnt her leg . i feel bad for her. but its funny some times.

side note i have a 1980 12a stock setup more or less. iam going to be doing a full rb header back. what do i have to do to shoot a fire ball when i shift pm me if u have the answer.

 

That was extremely painful to read.

 

Ok, i have the backfiring problem and I have a solution for all of you, its really quite simple, when you stop, even if you have been driving hard, pull up the handbrake, shift into 5th, slowly release the clutch and stall the engine, any gear will work but 5th has less chance of making car lurch (which makes you look like a total amateur), if the engines stalls it has spark all the way till it winds down to 0rpm and therefore all the fuel is burnt and no backfire. Works great.

Now I should become a Rx7club legend

This should probably go in FAQ, unless it only works for me, but im sure it should work for everyone.

 

n00b question... is it bad to deliberately stall your car like that? Well, actually, is it worse to deliberately stall it rather than let it explode on itself?

 

Yep, been there!

 

AAB Valve?

 

lol we all love that backfire ! why you guys want to get rid of it ? we have guys here in cape town that WANT their rotary to backfire when they shut it off lol