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post #1 of (permalink) Old 08-23-2004, 03:00 PM
BigJ
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Pulse Air Valves.

I am getting ready to get emissions tested and I am tuning everything up. I tried the search function as well as the primer with no luck.

My understanding is that the pulse air valves allow oxygen into the cat-con and the exhaust line to promote extra combustion. If the valves are stuck shut or clogged then there is less O2 available and HC's have the potential to be higher.

The question is: What if the valves are stuck open?
I know that "burping" exhaust into the carb intake is bad.
Would allowing a constent supply of air into the carb and exhaust make for better emissions?

Why wouldn't you want to have, say, a filter and a check valve on the supply tubes instead of a controled valve? Can you have too much air to the cat-con?

I know that it is controled for some reason. Just wondering if anyone knows it.
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post #2 of (permalink) Old 08-23-2004, 08:32 PM
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Re: Pulse Air Valves.

Lots of good questions there. Here's the Primer that you are looking for.

A Primer on the Jeep 258 with Carter BBD & Pulse Air Emission System by Dale Beckett

Here's another link to one of his pages.

Jeep Adventures Under the Hood

That should get you started and LEVE will likely jump in at some point.

Good Luck

Dale
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post #3 of (permalink) Old 08-23-2004, 09:22 PM
BigJ
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Re: Pulse Air Valves.

I guess I was unclear. I have read the 'primer'. I also looked in a Hayes manual, Chiltons manual, internet and asked my hotrod building neighbor. It says that the computer decides when to turn the pulse air valves on or off, but not what the computer needs to make a change on or off.

The pulse air valves never worked as far as I can tell, since I bought the <nobr>jeep</nobr>. I checked both of the hoses and valves and the hold pressure in the direction opposing flow. All of the lines are clear. I hooked a ported vacuum source to the pulse air valve (bypassed the vacuum solenoids) and for the first time ever I heard the reed valves vibrating and I could get a bouncing needle on a vacuum gauge.

I don't know if the vacuum solenoids are bad. If I knew what causes the computer to operate them to open the air valves to allow O2 to flow to the cat-con, I could simulate it and measure the vacuum at the line from the two solenoid valves that are supposed to operate the pulse air valves. Do the vacuum solenoids turn on when operating temp (computer in closed loop) is reached and then stay on? Like I said, since I have never seen them work, I don't know what conditions make them work.

Question: If I leave a vacuum source hooked up the the pulse air valves, so the are always open, will that be detrimental to passing emissions? Or should I just replace the vacuum solenoids before trying to pass emissions.

Thanks for the help though, I really do appreciate the reply!
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post #4 of (permalink) Old 08-24-2004, 06:36 PM
BigJ
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Re: Pulse Air Valves.

Just checked out the vac reservoir and all the vacuum lines. After isolating just about everything connected to the pulse air valves, the only thing I can deduce is that the at least 2 of the three vacuum solenoids are bad. Everything else works.

Can anyone tell me if the pulse air valves are normally open (operating) while the engine is running?

Thanks!
post #5 of (permalink) Old 08-24-2004, 09:56 PM
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Re: Pulse Air Valves.

Seems you are getting down to it... Talking to yourself isn't good.... I'll just post from time to time... [img]images/graemlins/grin.gif[/img]

Dale
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