87 B2600 Emissions help

Just want to thank all of those that have givin me input on the issue.

What I have chosen to do is keep the Weber carb and add some AIS valves to just get the thing to pass. I went to the local junk yard and looked around for some kind of stand alone pulse air injection system valve. from what I can see the Japanese manufacturers use pulse air injection and the domestic companies like air pumps to push air in. I found some valves from a Nissan 4 cylinder truck application. These have a vacuum valve that opens and allows air to flow through and add the exra air that the cats need. I also got a bunch of sensors and actuators from a feed back carb to see if I can get the computer to work and actuate the solinoids that actuate the reed valves for the AIS.

It is a bit of a hack modification but I think I can get it to work. I got the request for the pictures but the head is off right now and it would not help the issue. When I get the head back on I will show you all what I have done to get it to work.

I am hoping that the engine computer will work the AIS solinoids with out a few sensor inputs. I assume it will show a check engine light but as long as the valves open properly then Im golden.

To get the thing to pass the tail pipe test I think I will get some ethanol to "water down" the gas and clean up the exhaust. I can also retard the timing and get it hot before I go in for the test, it just has to pass once.

Dino. . . you need to be aware of a couple things while you are in the middle of fabrication. . .

The AIS on the B2/22 involves two systems.

You need to understand what they do so that you aren't working against yourself.

There are two discrete systems, which work at different times.

The first system has one tube and four ports directly ahead of the O2 sensor and first catalyst (precat). That is the one that was probably mangled by the bend-over and crimp crap.

That tube only allows air into the exhaust stream until he truck goes into closed loop. What it does is provide additional air to heat up the first of the two catalysts that these trucks use. Once the thermal switch on the radiator closes, that system no longer supplies air to the exhaust.

If that tube stays open, you end up with an excessively lean exhaust stream after the 02 sensor "wakes up" at 600 degrees, which would then feedback a "please richen" signal to the ECU mixture control.

The other two tubes are vacuum driven as exhaust pulses increase, which are used to introduce additional air (oxygen) into the exhaust stream to promote additional burning in the second catalyst. Those are open at all times, any time the exhaust vacuum overcomes the reed valve resistance in the air cleaner.

So the solenoids may not be as big an issue as much as getting rid of the visual problems.

mazda tweaker
My truck is a b2600 from 1987
I have been studying the wiring diagram and the engine bay. It looks like they left the vacuum solinoids for the first and second, air injection system. each solinoid controls a pair of reed valves. I will be using the two Nissan reed valves on one soilinoid and run the other two reed valves with another solinoid.

My investigation of the engine bay has turned up the connectors to the egr solinoid, purge solinoid, and a few other missing solinoids. My consern is will the solinoid valves for the Air Injection system function properly with out the carburator sensors and actuators. Is the engine computer smart enough to sense if the carb sensors are missing and will it go into some kind of limp mode and thus not allow the Air Injection System to function. The stock carb has a throttle position sensor and not a throttle switch like the b2200 carb. Will the engine computer function only with the engine speed from the coil and ignition system.

Any insight will help