cdrad51

I noticed yesterday that the hose going from the air pump to the pipe going to the main cat broke. I was going to replace it, but before that decided to test the pump itself. So i blocked the hose with my finger while the engine was running my and didn't notice any pressure. Does that mean the pump is not working or would I normally not be able to feel pressure by doing that?

Steve Shulz

The higher the rpm the more pressure. It is designed to flood the cat with air (solution to polution is dilution) When you smog test your doing it at a load so typically it wont come on until after 1100 or so. It does have a good bit o pressure not sure how much to be exact though. Is your car kinda loud air sounding when you get on it? With that pipe broke you should me makiing hella noise from air and exhaust through that pipe.

cdrad51

Oh good point, I'll try to feel the pressure while revving up and see. Noisy? you bet, but it was already, as the system has a leak somewhere in the cats, which has being going on since way earlier than when the hose broke. I haven't fixed the leak as that's probably what keeps the car running since the cats must be clogged as hell. I bought a Bonez converter system to remedy, I'm just waiting to get a new mid pipe and muffler to replace the whole thing. By then I want to make sure the air pump is operating properly to avoid premature failure of the main cat.

cdrad51

hmm did the same with the engine at 1500, felt nothing...

Steve Shulz

Do you have any air coming off the side of the ACV (the 3/4" hose going up to the carb on the drivers side) If you do then your ACV (like mine) is shot. Ive heard there is a rubber flapper that breaks and will cause this. There is also a procedure in the Haynes manual to adjust the timing of this device too, but it basically says if you can feel air coming out of (pic in the book) then replace the ACV.

cdrad51

I can test that, but would a faulty ACV valve cause the split air pipe to receive no air?

specRX7_22

to see if your pump is actually working at all.... remove the top of the air cleaner and put your thumb over the larger of the 2 holes (i think its the larger one) at the bottom of the air box. You should feel a significant amount of suction.

cdrad51

Even at idle or do I need to rev it up?

specRX7_22

At idle.... you should not need to rev it at all.

cdrad51

OK so I tried that and there is suction alright, so the pump is working. Now I need to figure out why air is not coming out of the hose going to the main cat.

specRX7_22

The ACV distributes air to 3 places....

1. from idle to 3000rpms, air is injected into the exhaust
ports
2. 3000+rpms air is vented into the air cleaner
3. at some other times it can be injected into the cat, it
looks like when the choke it on

specRX7_22

so i'm pretty sure that its OK that your not feeling anything at the cat.

cdrad51

I'm confused. I thought the air pump was supposed to supply a constant flow of air to the cats to aid combustion of toxic chemicals, and without it, there will be unburned fuel residuals that will eventually clog the cats.

Wankelguy

There is a check valve in the line that goes from the manifold to the converter. If this check valve gets plugged, no air can get to the converters.
Alternately, if the ACV goes bad, that could cause the same problem. Just a couple of possibilities.

cdrad51

I was checking the hose that goes from the manifold to the check valve, so that wouldn't be it. So it must be the ACV, unless I'm missing something. I hate the emissions system, it gives me a headache!

Wankelguy

Then open the garage door.


(sorry, I HAD to do it...)

cdrad51

no kidding. I was working in the engine bay with the engine running, and with a current exhaust leak, my eyes were watering within seconds!

cdrad51

any advice/tips from the pros/gurus/experts?