Auxiliary air valve tube construction for FMIC plenum and a Q

[gravelRX]

It's cold and my RX is having a time without a 'choke' because, I believe, I unhooked the AAV from the original plenum and plugged it up so I could run the FMIC with all the fabbed up piping.

 

I didn't think I would need the AAV. Well, I was lazy and didn't feel like adding the pipe to the plenum, let's be honest. Now it's cold.

 

 

The small pipe is the very thin metal tubing under the kidney bean air filter housing from a carb model. Couldn't stay on it very long with the welder because it was so thin so I "GASP" used a bit of the JB weld to make sure no leaking would occur. Notice picture was taken after the application of the JB weld. You really didn't want to see the welds, trust me.

 

Car wouldn't idle up when started. Sounded like a pro stocker lumping with the cams. I think this should take care of that.

 

Also getting bad gas mileage. Do you people think this system, or having it plugged, contributed to the bad mileage? Wouldn't the AAV get hot and lean out even without the flow of air? Am I understanding the mechanics of this system correctly?

 

I have a theory, What's yours? How about the small exhaust leak after the turbo, before the O2 sensor? Causes what?

 

I can smell it running rich too. Air/Fuel gauge is hooked up to the original O2 sensor, so it's just pretty lights. No real hard data.

 

 

Then again, better rich than lean.

 

 

Theories are welcome. And comments about the unfinished/unpainted clumb of fabrication welcome.

 

 

This small exhaust leak is going to cause me to finish the header/uppipe, I can see it coming.

 

 

Jay

[gravelRX]

Merry Christmas and a bump for the JB fab. Would really like input on the mileage issue.

 

 

Jay

[WJM]

I have not had my AAV plumbed in for months. Its just sitting there blocked off. After about 1 min of babaysitting the idle in sub 30*F mornings...it idles perfectly at 900...as it warms the idle increses to 1200 where I want it.

 

I get ~26 MPG around town and depending on traffic and weather...somewhere between 32~37 MPG in the interstate. I think you gas mileage may be affected by other things...O2 sensor? Lead foot? When i lead foot the RX the fuel goes fast...sub 20 MPG...eventhough Dragon trips (80% WOT) Ive yeilded ~22 mpg up there.

[Caboobaroo]

I have not had my AAV plumbed in for months. Its just sitting there blocked off. After about 1 min of babaysitting the idle in sub 30*F mornings...it idles perfectly at 900...as it warms the idle increses to 1200 where I want it.

 

I get ~26 MPG around town and depending on traffic and weather...somewhere between 32~37 MPG in the interstate. I think you gas mileage may be affected by other things...O2 sensor? Lead foot? When i lead foot the RX the fuel goes fast...sub 20 MPG...eventhough Dragon trips (80% WOT) Ive yeilded ~22 mpg up there.

 

Damn, looks like I'm going to be having to babysit my RX for about 5-10 minutes in the winter since it gets sub 10* in Laramie. I'm also planning on hooking my AAV back up in my RX but it doesn't fit in the stock location on the spyder intake. I'm going to be mounting it to the passenger side strut tower but it'll be out of the way. Let me know how it comes out Jay.

[rallyruss]

My RX had the air line plugged due to the FMIC installation by the last owner. I welded up a fitting to plumb it into the air intake where the little plastic muffler thing goes. Also have the bypass valve dumping in there also. Much nicer cold starting.

I doubt it has a big effect on your rich running condition.

An exhaust leak can effect your mixture when you are not under boost. somtimes they will suck in a little air between exhaust pulses. the additional o2 will tell the ECM that it has a lean condition and add fuel.

some more likely suspects would be the Coolant temp sensor and or connection.

A bad o2 will give you poor fuel mileage as well.

there are more things but those are most common.

[gravelRX]

Thanks for the insight RR. I'm going to go ahead and build the header so I will be getting into that back corner with the turbo. Taking it loose and making the uppipe work. So fun! Going to start with getting the leak fixed and see if that cures the bad mileage. Then I'll start addressing other issues like checking outputs on sensors and such.

 

Caboob, The AAV is essentially part of the thermostat housing and if you move it to the pass side strut tower your going to have to supply it with a coolant source so it will function properly. Are we talking about the same thing?

 

 

Will, My car has never been able to really get the 205/50's to spin excessively but right now I've got snowtires on the car and it will, in given circumstances, spin the 185/60/14's quite a bit. It's like finding a new toy or something.

that might have something to do with the mileage, Eh? I'm also getting a strong odor of rich exhaust after running the car harder than normal driving.

 

If an exhaust leak before the O2 sensor can cause a run rich situation without make the A/F gauge peak(one wire), then I've at least narrowed it down.

 

Tony (Meeky Moose) said that his TWE header on the RX wagon rubs his power steering lines. Does anyone else have that problem? I'm just now working on the 'up' part of the uppipe and I'm trying to get them spaced evenly between the engine and lower crossmember.

 

 

Thanks for the suggestions.

 

Jay

[WJM]

Yeah, the early TWE headers are designed for their drag car...no power steering.

 

My header and PS lines occupied the SAME place...so i fabbed up some new PS lines and ran them elsewhere.

[4WDFrenzy]

Hey if those are the pics of what you have done so far, it looks pretty good.

 

Got a quick question for you Jay. How much would you charge to fab up just the piping for the header(no flanges needed; can have the local exhaust shop weld them on when I get back to the States.)?

 

Patrick

[Caboobaroo]

hmm I'm guessing its not the same deal as what everyone else is talking about. Someone told me that what I have MIGHT be the AAV but now I'm not thinking it is. I'll snap a pic of it when I get back to Laramie and hopefully someone can help me out on what it is and what it does.