LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

A.I.R System Questions

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Old 09-11-2017 | 08:27 PM
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97rebuiltZ28's Avatar
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A.I.R System Questions

My current rebuilt LT1 now has about 1,200 miles on it, and since this rebuild I've noticed a slightly worsening exhaust leak that I pinpointed to be this hose https://imgur.com/a/NW8Md that is connected to this check valve on the air injection system. (Which I believe has to do with the A.I.R system) I already ordered the replacement hose and will be putting it on tomorrow.

Anyway, I have a few questions relating to this A.I.R system, and I searched all around and couldn't find the answers to these questions.

1. I read that the A.I.R system only runs through the first couple minutes after startup, but the exhaust leak continues throughout the entire running of my car. Is any of this information flawed? Does this system continue to flow throughout the entire running of the car?

2. Do you think that this leak has hurt anything in the past 1,200 miles?

3. The only codes I have are P0441(Evaporative Emission System Incorect Purge Flow) and also P0336(Crank Position Sensor) Do both of these codes correspond with this leak, or is there another problem?

Thanks!
Old 09-11-2017 | 08:56 PM
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Re: A.I.R System Questions

1. AIR is only operational during cold start and only for a few minutes to help heat up the cats. If a check valve is not functioning correctly, it could let exhaust gases back towards the rubber hoses (usually causing them to melt and fail). The solution would be to replace any faulty valve.

2. Leak could cause skewed O2 readings and therefore affect fueling.

3. Neither code is related to the AIR system.
Old 09-11-2017 | 09:12 PM
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Re: A.I.R System Questions

Originally Posted by shoebox
1. AIR is only operational during cold start and only for a few minutes to help heat up the cats.
Why do you suppose that the exhaust continues to leak out of that broken rubber tube then? Because that is clearly where the leak is coming from even after the engine had ran for 10+ minutes.
Old 09-12-2017 | 06:16 AM
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Re: A.I.R System Questions

Because you probably have a defective check valve, as I mentioned. That is the only way exhaust can travel that direction.
Old 09-12-2017 | 04:22 PM
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Re: A.I.R System Questions

Update: I replaced the hose and now the engine sounds butter smooth without that annoying leak sound! Also the P0441 code went off as of so far. I was also thinking more about that check valve and looking more at its location and what it does and have a hypothesis that hopefully isn't too stupid. I'm thinking that maybe the constant leaking was because the air was leaking before the check valve and not after it, therefor the valve could still be working. Is that a possibility or is that totally stupid?
Old 09-12-2017 | 09:20 PM
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Re: A.I.R System Questions

If the check valve was allowing exhaust to flow out of the torn hose, the check valve is leaking. It's job is to open and allow the air to flow into the manifold when the AIR pump is running, and to close when AIR is not running, to prevent exhaust from flowing back toward the hose, tubing and pump.

If you still hear the exhaust leaking toward the hose, the hose is eventually going to melt.

If your car did not get the AIR system recall done, the leaking exhaust can flow back to the pump, the water vapor in the exhaust gas condenses, and corrodes the pump. Eventually the pump rusts, seizes up, and starts blowing the fuse.

Listen to Rob/Shoebox.
Old 09-12-2017 | 09:49 PM
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Re: A.I.R System Questions

I will, thanks for all the help guys. I learn more everyday from this site.




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