I have an 84 hatch. I'm looking for the anti-afterburning valve, anti-backfire valve, or the aav what ever it's called. I can't find it. Can someone snap a picture please.

I have an 84 hatch. I'm looking for the anti-afterburning valve, anti-backfire valve, or the aav what ever it's called. I can't find it. Can someone snap a picture please.

Actually, I think you're looking for the air suction valve.

 

Do a search on this (might be in the USRM). The newer ASV uses the same flapper valve as the older ones. NEW price is under $20 and all you need to do is open it up and remove the valve and install it in your old ASV housing.

 

Found this in the USRM: http://www.ultimatesubaru.org/forum/showthread.php?t=49926

Unfortunately the pics come out with "x"; probably because the links to the pics got lost with the conversion to the current board layout.

Edited February 10, 200917 yr by edrach

I finally found the thread I was looking for. There's another link inside it that might be helpful too.

 

http://www.ultimatesubaru.org/forum/showthread.php?t=30378&highlight=suction+valve

 

And another:

http://www.ultimatesubaru.org/forum/showthread.php?t=2569&pp=10&highlight=Air+suction+valve

Edited February 10, 200917 yr by edrach

My main goal is to eliminate the backfire I'm getting when shifting. It sounds like its just a feature of these cars but I need it to go away because I'm planning a trip to the sand dunes and I don't want to explain to the ranger why I burned down half the surrounding forest. Anyway are you saying that there isn't an Anti-Backfire Valve on my car or are you saying that I should be looking at the Air Injection System and the Air Suction Valves?

 

Thanks for the help.

I just found a picture of it. Some one was asking the same question. But I still need to know if I should check the Air Suction Valves.

 

Thanks Again.

I don't have a pic but the aav on my 87 brat was just behind the driver's side strut tower in the engine bay. As far as stopping the backfire, I have found that along with the AAV you should check for any air leaks into the exhaust system including the flapper valves. My AAV couldn't keep up with the backfires that where caused from bad flappers in the air induction system. I recently changed over to SPFI and gutted the air induction system out so the backfire was cured. Hope this is of some help

 

Shawn

The AAV does not affect backfireing.

 

You need to fix your exhaust leaks in the y-pipe and repair, replace, or eliminate the air suction valve(s).

 

GD

Found this in the old USRM after McBrat was kind enough to repair the link:

 

http://www.indysworld.com/80s/general/USRM/AirSuction/airsuctionvalve.htm

OK Thanks.

If I remember correctly, you can disable an air suction valve by removing the cover and flipping the reed over, then reassemble. we used to do this so that the valve was still there for the emissions inspector.

If I remember correctly, you can disable an air suction valve by removing the cover and flipping the reed over, then reassemble. we used to do this so that the valve was still there for the emissions inspector.

 

Inserting a quarter between the valve and the pipe going to the head is easier and quicker.

 

GD

I know you guys have horror stories of them going out but why would I want to disable them? Shouldn't I want them functioning so that they can add oxygen to the exhaust? I thought you needed them for the catalytic converter to function correctly? Otherwise I still get the bang bang every time I shift, right?

I'm sorry for ever doubting you guys. I just opened up the air suction valve and it's toast. Melted the silencer, plastic in my intake and everything. Crap.

Dennis where are you, yours backfires or did you fix that?

are you backfiring out your exhaust or your intake??

Backfiring out the exhaust is typical of leaks in the y-pipe or early in the mid-pipe section. The oxygen introduced into the leak combines with unburned fuel and ignites in the muffler.

 

The ASV's fail (reed valve snaps), raw unburned exhaust melts the plastic ASV silencer, and the melted plastic gets sucked right into the carb. Been there, done that..... I was able to remove the plastic bits and drive on. I was lucky. Sometimes it really screws stuff up and the carb has to be torn down to fix it.

 

EA81's rarely (if ever?) backfire out the intake - they are gear timed and as such the valve timing is fixed and to cause an intake backfire an intake valve would have to hang open.

 

GD