Auxilary Air Valve question?
12-20-2010, 03:44 PM
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Auxilary Air Valve question?
I read some of the threads searching for idle issues and surging. I read that the 'tape over the hole' method inside the throttle body (from AAV) will help diagnose the issue.
When I tape over the hole my idle went way down. However, I still have to bottom-out the idle adjustment screw and now it sounds like it wants to die when I apply the brake...(which before had NO affect).
I plan to clean out the AAV and check to see if it is obstructed. I know I need to check the resistance of the coolant temp sensor as well. I read several threads involving EGR but they seem more like a cat fight than anything else.
Is the AAV adjustable? Thanks
When I tape over the hole my idle went way down. However, I still have to bottom-out the idle adjustment screw and now it sounds like it wants to die when I apply the brake...(which before had NO affect).
I plan to clean out the AAV and check to see if it is obstructed. I know I need to check the resistance of the coolant temp sensor as well. I read several threads involving EGR but they seem more like a cat fight than anything else.
Is the AAV adjustable? Thanks
12-20-2010, 04:01 PM
#2
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AAV is not adjustable, its a heat activated gate that opens and closes.
Testing it is relatively easy. When the engine is dead cold, the valve should be open, allowing air to flow through the AAV. Pinch the hose going to the throttle body, and the engine RPM should drastically decrease, and the engine may even die.
When the engine is warm, the valve should close, preventing air flowing through the AAV. Pinch the hose going to the throttle body, the engine RPM should hardly drop at all.
There is also a resistance test to perform on the electrical connection of the AAV, I can't recall what it should read across the terminals though.
For surging idle, the culprits could be the AAV, TPS, or AFM. There is a slight chance that the Throttle body itself could be causing it, but this is rare. I would start with checking the resistance of the AFM, TPS, and do the pinch test of the AAV
Testing it is relatively easy. When the engine is dead cold, the valve should be open, allowing air to flow through the AAV. Pinch the hose going to the throttle body, and the engine RPM should drastically decrease, and the engine may even die.
When the engine is warm, the valve should close, preventing air flowing through the AAV. Pinch the hose going to the throttle body, the engine RPM should hardly drop at all.
There is also a resistance test to perform on the electrical connection of the AAV, I can't recall what it should read across the terminals though.
For surging idle, the culprits could be the AAV, TPS, or AFM. There is a slight chance that the Throttle body itself could be causing it, but this is rare. I would start with checking the resistance of the AFM, TPS, and do the pinch test of the AAV
12-20-2010, 04:15 PM
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AAV is not adjustable, its a heat activated gate that opens and closes.
Testing it is relatively easy. When the engine is dead cold, the valve should be open, allowing air to flow through the AAV. Pinch the hose going to the throttle body, and the engine RPM should drastically decrease, and the engine may even die.
When the engine is warm, the valve should close, preventing air flowing through the AAV. Pinch the hose going to the throttle body, the engine RPM should hardly drop at all.
There is also a resistance test to perform on the electrical connection of the AAV, I can't recall what it should read across the terminals though.
For surging idle, the culprits could be the AAV, TPS, or AFM. There is a slight chance that the Throttle body itself could be causing it, but this is rare. I would start with checking the resistance of the AFM, TPS, and do the pinch test of the AAV
Testing it is relatively easy. When the engine is dead cold, the valve should be open, allowing air to flow through the AAV. Pinch the hose going to the throttle body, and the engine RPM should drastically decrease, and the engine may even die.
When the engine is warm, the valve should close, preventing air flowing through the AAV. Pinch the hose going to the throttle body, the engine RPM should hardly drop at all.
There is also a resistance test to perform on the electrical connection of the AAV, I can't recall what it should read across the terminals though.
For surging idle, the culprits could be the AAV, TPS, or AFM. There is a slight chance that the Throttle body itself could be causing it, but this is rare. I would start with checking the resistance of the AFM, TPS, and do the pinch test of the AAV
TPS is new and in adjusted to specs. AAV has the hole in the TB taped over (which greatly decreased my HIGH idle but not enough) AFM met specs too... This is why I am confused... Thanks
12-21-2010, 01:35 PM
#5
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Vacuum leaks possibly, maybe at the booster. You said your idle is turned way down, so I'm not thinking that its turned too high. Check over all the hoses, and check routing.
You should test the AAV like I mentioned and ditch the 'tape', you need the AAV open for cold starts/extended soak startups.
When you tested the AFM, did you move the flapper door and check that there is no drastic spikes in resistance?
You should test the AAV like I mentioned and ditch the 'tape', you need the AAV open for cold starts/extended soak startups.
When you tested the AFM, did you move the flapper door and check that there is no drastic spikes in resistance?
12-21-2010, 02:02 PM
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Vacuum leaks possibly, maybe at the booster. You said your idle is turned way down, so I'm not thinking that its turned too high. Check over all the hoses, and check routing.
You should test the AAV like I mentioned and ditch the 'tape', you need the AAV open for cold starts/extended soak startups.
When you tested the AFM, did you move the flapper door and check that there is no drastic spikes in resistance?
You should test the AAV like I mentioned and ditch the 'tape', you need the AAV open for cold starts/extended soak startups.
When you tested the AFM, did you move the flapper door and check that there is no drastic spikes in resistance?
The AFM seemed fine (is it supposed to stay open a hair and not close all the way?).
How does the brake booster get checked?
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