Wanna see inside an AAV?
03-06-2006, 01:38 AM
#1
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Wanna see inside an AAV?
Found that part of my hard cold start was due to a DOA aux. air valve (AAV), so what does one do?? Tear it apart. (don't worry kids, i've BTDT before 
)
Symptoms: car hard to start cold, valve wouldn't open when cold.
Rememdy: drill out/off 4 aluminum rivets, custom tweaks via needle nose pliers to the bimetallic plate (piece that the two wires attach too).
Result: after 4 tweaks and heat/cold cycles, valve works like butta'.
)Symptoms: car hard to start cold, valve wouldn't open when cold.
Rememdy: drill out/off 4 aluminum rivets, custom tweaks via needle nose pliers to the bimetallic plate (piece that the two wires attach too).
Result: after 4 tweaks and heat/cold cycles, valve works like butta'.
03-06-2006, 02:20 AM
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Scott, I'm glad you made this post. I debated taking mine apart when I had it off recently. But I was afraid there would be lots of pieces that may fly everywhere. I just lubed it up good and worked the valve with a screwdriver to keep it from sticking. But I'm still having some pretty rough cold starts. The resistance test falls within WSM specs, but I suppose mine still may need to be adjusted. So, how exactly were you tweaking it? Did you just stick it in the oven briefly to heat it up, or did you just stick it back on the car? Did you just get some small bolts to hold it back together? Sorry for all of the questions. Just curious on some of the details. Thanks in Advance.
Chris
81 auto, 63k miles
Chris
81 auto, 63k miles
03-06-2006, 02:29 AM
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Chris;
I applied +12v to the plug (brown is ground) and door takes ~6min to go full travel. Heating in an oven won't effectively heat metallic strip. Let cool for ~15 min or stick in beer fridge for 3 min.
4 small machine screws backed by lock washers/nuts finished the job.
In this case the heating element (wire and strip) was fine. I've rebuilt a few where that was the problem.
I applied +12v to the plug (brown is ground) and door takes ~6min to go full travel. Heating in an oven won't effectively heat metallic strip. Let cool for ~15 min or stick in beer fridge for 3 min.
4 small machine screws backed by lock washers/nuts finished the job.
In this case the heating element (wire and strip) was fine. I've rebuilt a few where that was the problem.
03-06-2006, 02:42 AM
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Thanks! I'm going to go ahead and pull mine off and check it out. Also, I remember chunks of something coming out of mine when I was spraying lube in there. I would shake it, and debris would fly out. Now that I look at your pics, I think it may have been the wire insulation. I guess we'll see.
Thanks!
Chris
Thanks!
Chris
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03-06-2006, 11:47 AM
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LOL that did make me smile Scott. No, I think not all know what this thing is and where it is and what years it works on. Having had a CIS 911, I am all too familiar with it ..... I saw one on an '85 Euro engine last night which surprised me.
03-06-2006, 03:26 PM
#12
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That's cool. Good job!
I replaced my cold start system with a Temp II faker circuit, which works fine down to about 25F.
One reason I think you need that extra air, besides the dino oil viscosity, is to clear out water and gas condensation. I have to rev it up to 2000 for a few seconds after the first start of the day, or the car will bog on the first acceleration.
I replaced my cold start system with a Temp II faker circuit, which works fine down to about 25F.
One reason I think you need that extra air, besides the dino oil viscosity, is to clear out water and gas condensation. I have to rev it up to 2000 for a few seconds after the first start of the day, or the car will bog on the first acceleration.
03-06-2006, 07:20 PM
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Scott M. wrote:
"Found that part of my hard cold start was due to a DOA aux. air valve (AAV), so what does one do?? Tear it apart. (don't worry kids, i've BTDT before )
Symptoms: car hard to start cold, valve wouldn't open when cold.
Rememdy: drill out/off 4 aluminum rivets, custom tweaks via needle nose pliers to the bimetallic plate (piece that the two wires attach too).
Result: after 4 tweaks and heat/cold cycles, valve works like butta'."
Thanks. A keeper.
Let me make sure I have this right. The bimetallic strip moves left as it heats, allowing the spring to pull the valve closed, right?
How far did you have to tweak it?
I wonder why the air hole in the plate is such an odd shape?
My visual imagination has gone downhill, it took a cut-out made from an index card to figure it out. ;-(
"Found that part of my hard cold start was due to a DOA aux. air valve (AAV), so what does one do?? Tear it apart. (don't worry kids, i've BTDT before
)Symptoms: car hard to start cold, valve wouldn't open when cold.
Rememdy: drill out/off 4 aluminum rivets, custom tweaks via needle nose pliers to the bimetallic plate (piece that the two wires attach too).
Result: after 4 tweaks and heat/cold cycles, valve works like butta'."
Thanks. A keeper.
Let me make sure I have this right. The bimetallic strip moves left as it heats, allowing the spring to pull the valve closed, right?
How far did you have to tweak it?
I wonder why the air hole in the plate is such an odd shape?
My visual imagination has gone downhill, it took a cut-out made from an index card to figure it out. ;-(
03-06-2006, 09:22 PM
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Matt;
The AAV just allows air to bypass the throttle plate at cold engine temps to help raise rpms/increase air flow/better atomize fuel.
Will;
Your thinking is correct. I had to bend the strip about 1/8" to the right (in pic). It is somewhat of a trial and error procedure to get the flap to fully open.
The flap is odd shape (i guess) to allow varying amounts of air to flow at various stages of warm-up. The flap never fully stops all air, as evidenced by the last little square of opening in the flap.
The AAV just allows air to bypass the throttle plate at cold engine temps to help raise rpms/increase air flow/better atomize fuel.
Will;
Your thinking is correct. I had to bend the strip about 1/8" to the right (in pic). It is somewhat of a trial and error procedure to get the flap to fully open.
The flap is odd shape (i guess) to allow varying amounts of air to flow at various stages of warm-up. The flap never fully stops all air, as evidenced by the last little square of opening in the flap.