my car just started backfiring when i shift what causes this and is it leathal to my engine>

89 gxl
custom exhaust duel 3 inch pipe from the after the first pre cat no cats
removed the butterflies on the thrtle body you know wich ones the closest one to the intake filters

removed power steering other than that car preaty much stock

can you help me solve this ..???????
and what i can do to fix it????

ive had my exhaust for about 5months now but it just started backfiring

 

All rotaries do it. It just becomes more noticable when you open up the exhaust.

 

no the bacfire im talking about becomes very anoying .

ive had about 7 rx7s and non of them did this backfire it backfires every time i shift gears 2nd 3rd 4th and 5th very anoying

 

does this occur at ANY RPM? or just after the upper range? my n/a backfires when shifted above 6K or so.....but thats due to the N1 system not harmful...if you have no cats and shift up high you should be shooin' flames! hehe...

 

it happens at any rpm range above 2k

 

help needed here please .....

 

Mine does it at almost any RPM, I don't see anythign wrong with it. If it does it a whole lot might want to check for exhaust leaks. Who did you exhaust work?

 

you should check your spark plugs or the wires.

 

ok scince i just replced the clutch today scince you have to remove the exhaust system out i had a damm pacesetter header and put it in just to make sure i didnt have any leaks hoping that would take care of the backfire . but its still doing it so its not an exhaust leak


running rich??????running lean???????

ps : i was told that if you backfire on the intake you are running lean
and backfire on the exhaust means running rich.
is this true????????


help me out here ....

 

Well putting a header in is going to make it backfire if its not already more than likely. Our cars are going to backfire, they just do. If you didn't change what is behind the header how do you know its not leaking back there though?

 

because i took the hole thing down my self with a friend of mine
we lifted the car on a lift and check it out and the car has preaty much brand spanking new tubing from header to the rear new mufflers
i used 2 1/2 pippes

 

yeah, if you're backfiring out the exhaust you're running rich i would think...

 

i think i might change my plugs and wires see if that helps anything if not no harm done i was thinking on replacing them any way
might be a good time to buy the safc hehe

 

I am not sure what kind of exhaust you have but if there are any connections in it then they could have leaks that you can't really see. Not saying thats the case but could be. But you prolly are running rich & if you say that you are gunna change the plugs/wires then they prolly need changed anyways. Ya if you can afford the S-AFC then go for it, I think thats a real good investment, especially on an NA. Gives you some control over your car.

 

i am a computer technician during the week . but just started working in a rice roket shop installing body kits and stiker stikers and more stikers , billet grills on saturdays only , good thing is i can get stuff at cost he he. so safc only cost about 200$ fo me

 

Man you should hook some other people up on here

 

let me get mine first then ill see what i can do hehe

 

i still need to know what causes the backfire while shifting at any rpm range

 

I think I heard theres something that can be adjusted to control the backfire, but I really don't know if its true.

 

backfire blues come on its driving me nutttttttttttttssssss

backfire when shifting at any rpm range.
what could this be????

 

try checking your TPS, and dashpot
I dont know if an exhaust leak would do it but you can always do the ATF trick and trust me you will find every exhaust leak you have in your system, and you get a little cleaner motor to boot.

is your car runningreally rich also
if so that mixed with your open exahust could cause that, but for the most part you get a header and your car is going to pop a little bit no matter what

 

yes i know rx7s like to backfire... ive had about 5 of them diff years

but they never backfired like this .....
i know i dont have exhaust leak because i took of the exhaust system with my friend and checked it out.

on a side not i will hook up my air/fuel gauge just to see how rick/lean im running.



could it be the acv????

 

You still have an ACV on your car with no cats? Do you still have the air pump also? I am confused here, since the main purpose of the ACV is to inject air into the exhaust ports or main cat to help the cats do their job. Anyway, there is a third function of the ACV, and that is the anti-afterburn valve. It injects air into the intake when you release the throttle to prevent afterburn during that rich condition. If this valve has frozen/sprung a leak, you will experience the problem that you described. Of course, you need an air pump for this to work.

Irv, Keith's dad

 

uh.,.....what is backfire? what does it do, sorry for a newbie question, just like to know, thanks.

 

Man, sorry but being a newbie has nuthin to do with not knowing what backfire is. It is a loud noise, some are mistaken for a gun shot of sumin. It comes from your exhaust, usually after you let off the gas.