rx7convert22

Been trying to figure out why I failed my smog test. I confirmed my air pump is pushing a lot of air. I then detached the hose that connects to the split air pipe that feeds the cat. We had it in neutral and revved the engine a few times, but felt no air coming out of it. Should some air have been coming out? What do you need to replace to fix this if it is incorrect. Thank you.

J-Rat

iTrader: (2)

You have to read the FSM, but IIRC the pump doesnt supply air at idle...

HAILERS

1. The airpump supplys air to the Exaust Ports and the split air pipe. The Exaust Ports are where most of the air should be going. Exaust ports as in where the exaust manifold mates with the engine.

2. Tell you what about that split air pipe. Remove the end on the catalytic converter. Put it in a pail of water (attach a hose to it if you have to). Start the engine and watch the bubbles. Now get in the car and put the transmission in FIFTH gear (clutch in). Now the bubbles should really bubble.

3. About the acv. Do this. Remove the large hose off the bottom of the acv. With the engine hot and at idle, feel the air coming out of the large nipple on the bottom, where the large hose was. Now reach over and pull the BLUE plug off the Relief solenoid on the other side of the engine. The air exitiing should really start blowing now. Then put the blue plug back on the solenoid. The air should almost all stop coming out.

4. Or do this: Engine hot and at idle. Hose off the bottom of the acv. Rev the engine over 3800 rpm. The air should now really, really come out strong.

5. So how does your car compare to the above results?

rx7convert22

Here is what I did so far:

I did remove the large hose on the bottom as you said, and a lot of air came out of that especially when the engine was revved out.

Not much though came out of the split air pipe when revving though. Does the car have to be in 5th for air to really come out of here? What doesn't make sense then is how is your cat supposed to light correctly if the cat only really gets air in 5th gear?

I know for a fact during the whole smog test the car was never in 5th gear.

HAILERS

The air that goes to the catalytic converter, goes to the catalytic converter thru the Exaust Ports MAINLY on a NORMAL car. See the diagram in the fsm.

In the exaust ports is where the airpump air gets mixed with exaust gasses prior to getting to the catalist inside the converter. That's how it's meant to work.

If your getting a large amount of air at the bottom of the acv, then hardly any air is getting to the catalytic converte. It's being dumped into the right front fender where it does no good.

If your getting a large amount of air out the bottom of the acv, AND when you pull the Blue plug off the Relief solenoid the amount of air does not change, then the hose for the acv are swapped around/missing/ plug off the solenoid/got me.

With a older car you will get some air being bypassed thru that bottom hole due to the acv having old diaphrams. But there should be a dramatic outflow of air as you rev the engine and reach 3800 rpms. Rev it slowly and see if you don't get a dramatic increasse just as you reach thirty eight hundred rpm.

But if it's always flowing out the bottom and it's more than a whisp, then you've problems with the acv/relief solenoid signal/ tps setting.

Bottom line is you have to keep that air that is escaping out the bottom of the acv, to go where it was meant to go.....the exaust ports.

Ah heck. Plug the bottom hole and put the hose back on and go get it tested. Might work and there will be no visual effects of you having done so. You plug it and the air HAS to go to the exaust ports.

IF your obsessed with having air go out the split air pipe, then unscrew the rear solenoid on the acv and carefully remove the spring and poppet valve. The reinstall the solenoid without those two items. The air will increase tremendously out the split air pipe As Long As the Air is not being dumped out the bottom of the acv. The air can only be ait one place at a time. If it's being dumped out the bottom, theres not enough pressure for it to go to the exaust ports or the split air pipe.

HAILERS

&&&&&&& Not much though came out of the split air pipe when revving though*********

Because all the airpump air is going out the bottom of the acv into the fender.

&&&&&&&&cat only really gets air in 5th gear?************************

Remove the acv sometime. You'll see a checkvalve b/t the acv and the intake. It will have *spokes* or will look like a spoked wheel. The airpump air goes thru that checkvalve, then to the exaust ports to mix with the exaust gas then on to the converter.

rx7convert22

I am thinking of just attaching the air pump right to the cat for my smog test. If I pass then I am thinking of just replacing the cat with a rb silencer pipe and just save the cat for my next test in over 2 years from now. ACV is kind of worthless if I no longer use a cat. Sound like a good enough of a plan?

From there I have to figure out why my 5th and 6th ports aren't working, but that is a different problem