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ACV/catalytic converter question

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Old 01-06-08, 12:54 PM
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ACV/catalytic converter question

I failed emissions miserably a while back. I registered in a non emissions county because of that. I came up with the idea of connecting the ACV outlet directly to the split air pipe leaving the factory rubber line coming out of the back of the engine unconnected. Is there a down side to this? Or is it perfectly ok? It seems to run a bit better.
Old 01-07-08, 04:14 AM
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actually it has been done..there should be threads on it too..I know that some guys use a T connection from the Air pump outlet,and run it into the split air tube..it pumps "good air" to the cat...Try searching "Failed Emissions".you should get some info just with that Title.
Old 01-07-08, 11:31 AM
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i figured it should be ok. what RPM does the air pump NOT supply air? The rubber split air line feels like it barely supplies any air at all. It seems to have cut down on the pop corn sound as well.
Old 01-07-08, 03:39 PM
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IF you have the airpump connected to the split air pipe directly, then the pump pumps air all the time the engine is running.

If you have the piping connected in a normal manner, then there are a number of scenarois where air is and is not sent to the split air pipe.

The Relief solenoid controls the ACV relief valve. The relief Valve sends the airpump air overboard into the silencer in the right fender when the solenoid is De-energized. It is de-energized about 90% of the time when driving the car.

At idle, no air is sent to the split air pipe. It's all sent to the exhaust port. You know exhaust ports, right. The items just prior to the exhaust manifold. Prior to the 02 sensor FYI. Prior to the catalytic converter FYI.

When you first start out Driving, both Relief and Switching are energized, meaning No air is sent overboard into the silencer in the fender. The Switching being energized MEANS the passage to the exhaust ports are blocked by the switching poppet and air is sent to the split air pipe.

After driving for approx 120 seconds, the Relief solenoid is de-energized and only the Switching solenoid is energized, Meaning the relief valve in the ACV is open and the airpump air is being sent overboard into the silencer in the right front fender. The Switching solenoid being energized MEANS the switching poppet is blocking air going to the exhaust port, and there is a Possibility of some air actually going to the split air pipe. But, remember, the relief valve in the ACV is wide open and dumping the airpump air overboard. So how much air could possibly go to the split air pipe? Zippity imho.

There are scenarios when driving when the Port air solenoid, switching solenoid will energize/de-energize. Like going up a steep hill the Port air solenoid will come on momentarily or going down a steep hill the Switching solenoid will come on momentarily. Momentarily is just that. If you keep on a driving down the hwy, the NORMAL state is just the Switching solenoid energized all by itself, MEANING the Relief solenoid is NOT energized which means the airpump air is being sent overboard into the silencer in the right front fender.

The reason for this imho, is that when driving at a steady speed, the ECU is in closed loop and the AFR is in the 14.7 afr range. IDEAL for a catalytic converters effieciency.

Also, anytime the engine rev's over 3800rpm the Relief solenoid and relief valve in the ACV open and dump the airpump air overboard.

Opps, The first and third jpg are the same animal. I've lost the other jpg. I'll go find it. Later.

First jpg is at idle. Second jpg is after you've driven for approx 120 seconds or more. The one not posted is the time b/t idle and the 120 seconds where air goes to the split air pipe.
Attached Thumbnails ACV/catalytic converter question-acvidle.jpg   ACV/catalytic converter question-acvafter120seconds.jpg   ACV/catalytic converter question-aircontrolvalvena.jpg  

Last edited by HAILERS; 01-07-08 at 03:49 PM.
Old 01-07-08, 04:07 PM
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Attached Thumbnails ACV/catalytic converter question-acv120seconds.jpg  
Old 01-07-08, 10:34 PM
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So would that mean that someone directly linking the "air pump dump air" to the split air pipe is supplying too much air the the converter? If so I suppose that would shorten the life of the converter as a downside? What else could be a downside if so?

If I'm understanding this correctly that is...

Also how clean is the air coming out of the standard (hooked up OEM spec) split air line? It seems now that it is disconnected and loose it smells like old gas fumes being burned? Would it be wise to leave it disconnected or should it be capped off?
Old 01-07-08, 11:21 PM
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When the air does go to the split air pipe, it should be fresh air. It does not mix with anything. It just goes from the airpump thru the ACV (if the switching valve/solenoid is energized), then to the pipe on the catalytic converter. Assuming the spoked shaped checkvalve is installed b/t the ACV and the maifold.

If you run the airpump air directly to the split air pipe where it constantly, hour after hour sends airpump air to the converter, I don't think that converter will be worth much a year from now. Try it out and write back next year after you get it inspected by a inspection station.
Old 01-08-08, 11:39 AM
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Well what do you know... I have a 1 year warranty on the cats I don't have to test since I can register out of my parents house in a non emissions county... but it would be nice to be able to pass again.
Old 01-08-08, 12:51 PM
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if it is a turbo, disconnect the wastegate rod and that will boost your numbers greatly.

I did the air pump directly to the cat, then removed my cat after I passed, so i can reuse it for like 10 years...
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