A modified air pulse system...sos

[JayRamb]

http://home.sprynet.com/~dale02/aircl.htm

I have an issue. Hope you can help me.

I purchased my 84 Eagle last year. It has the pictures of my issue in the above description and diagram. The pulse air tube foro this hole, that is rusted in the picture is missing all together!

Must I reroute my vacuum lines or stip? It may be going to take too much to try to route that steel tube from underneath the engine and the air valve.

[BenM]

The tubes are available for the lower part, from the reed valves on down. The upper metal and rubber parts to the air cleaner can be replaced by a couple of valve cover breather filters, they just need to filter the air so dust doesn't hurt the vacuum and reed valves. Just plug the air cleaner holes so dust doesn't get in the engine.

Those big hoses exist just to feed filtered air from the air cleaner to the exhaust.

[jim]

If you can do without them where you live they can be eliminated.  Mine are off for bench testing.  It has been a very long test.

[wagoneerhauler]

Those big hoses exist just to feed filtered air from the air cleaner to the exhaust.

Do today's converters need additional air to function correctly?  It seems as though none use the air injection anymore (for the last 20 years or so).  I would rather run a converter than not but it seems it shouldn't be such a complicated system.

[philotomy]

I have just a cat on mine ,no tubes,no o2 sensor there at least,and I have a clifford header w/ no o2 sensors there either,seems to work fine but mine has been converted to fuel inj.so the computer and other bits may be helping out in that respect.

[BenM]

It's not cat technology that's changed, it's fuel delivery technology. The two tubes have different functions.

The upstream provides air to the exhaust when the engine is cold and rich to allow the fuel to continue burning (if possible) and ignite the cat sooner. The downstream (going into the cat) is for the second stage of the cat.

Stage 1 in a cat is designed to work in a low-oxygen environment and strip the oxygen from NOx and similar compounds. It produces oxygen.

Stage 2, which is after the downstream tube, takes oxygen, and converts carbon monoxide and some unburnt hydrocarbons and completes their burn. The extra oxygen is to allow the engine when not producing enough NOx to provide enough oxygen to eliminate carbon monoxide.

What fuel injection does is to cycle the engine rich/lean in a fast, but slow enough cycle to make sure that both parts of the cat can do their job. Each part does have the ability to "absorb" a certain amount of pollutant, so this system works pretty well.

Carbs don't cycle, so the engine relies more on EGR and downstream injection to provide the correct conditions for the cat to work.

[JayRamb]

It's not cat technology that's changed, it's fuel delivery technology. The two tubes have different functions.

The upstream provides air to the exhaust when the engine is cold and rich to allow the fuel to continue burning (if possible) and ignite the cat sooner. The downstream (going into the cat) is for the second stage of the cat.

Stage 1 in a cat is designed to work in a low-oxygen environment and strip the oxygen from NOx and similar compounds. It produces oxygen.

Stage 2, which is after the downstream tube, takes oxygen, and converts carbon monoxide and some unburnt hydrocarbons and completes their burn. The extra oxygen is to allow the engine when not producing enough NOx to provide enough oxygen to eliminate carbon monoxide.

What fuel injection does is to cycle the engine rich/lean in a fast, but slow enough cycle to make sure that both parts of the cat can do their job. Each part does have the ability to "absorb" a certain amount of pollutant, so this system works pretty well.

Carbs don't cycle, so the engine relies more on EGR and downstream injection to provide the correct conditions for the cat to work.

EGG

[wagoneerhauler]

So if these injection tubes are not present will the cat plug up sooner?  It won't be able to function as intended and thus won't get hot enough.?  So if your air injection system is not operable you'd be better off without the cat then?

Thanks for the explanation Ben.

[philotomy]

Well,I guess I DO have an O2 sensor at the base of my header,but the  aftermarket (and smaller)cat doesn't have any air tubes...
 

[BenM]

So if these injection tubes are not present will the cat plug up sooner?  It won't be able to function as intended and thus won't get hot enough.?  So if your air injection system is not operable you'd be better off without the cat then?

Thanks for the explanation Ben.

It'll just ignite late and be less efficient. Only soot from running rich should clog one, and if you do some highway driving often enough, they're supposed to self-clean.

The pebble-filled ones are prone to clogging as things break down, but monolithic (all modern, many older) cats generally rust away first.

[JayRamb]

Our AMC CATS were/are stainless steel...guaranteed for the life of the AMC; similar to what they had for their early 60's cars which had Ceramic Coated Mufflers. If they failed, AMC/Rambler would replace for free. My neighbor who had an 84 Eagle, had her CAT replaced for free by AMC in 1987.

[BenM]

Our AMC CATS were/are stainless steel...guaranteed for the life of the AMC; similar to what they had for their early 60's cars which had Ceramic Coated Mufflers. If they failed, AMC/Rambler would replace for free. My neighbor who had an 84 Eagle, had her CAT replaced for free by AMC in 1987.

I blew all the pebbles out a few years back, I wonder if Chrysler would have honored the warranty?