Tomorrow evening works for me. Time? I'll have to rest up to keep up w/you.

I agree that we don't need to inject air into the exhaust just before the cat. But, I don't think we want to cap it off or the pump will have to work against a lot of back pressure. Should let it go back to the atmosphere.

Anyway, if someone can tell us how to cause the system to tell us the code we should pull that before going further. Then we can put an AIR pump on awa install the manifold on the back of the heads (boy, will the lift come in handy for that) and plumb up to the diverter valve. Btw, I may have the manifold-to-head gaskets awa 2 diverter valves - assuming '82 valves fit an '86.

 

It injects fresh air into the cat when the engine is warm, and switches the air flow to atmosphere on deceleration or at idle. It injects air into the exaust manifold when the engine is cold.

Not exactly. The computer can tell by the O2 sensor, and the TAD/TAB solenoids. Here's how.

When the air is being injected into the exaust manifold, the air leans out the exaust and will cause a leaner reading on the O2 sensor, more oxygen. When the air flow is divereted to the cat, the O2 sensor reads less oxygen. The computer can take those different readings from the O2 sensor, and time them with it's switching of the TAB/TAD solenoids to discover if the thermactor system is working or not.

 

The air is injected into the exhaust ahead of the cat, but behind the O2 sensor, which is in the exhaust manifold. So, all the computer can tell is whether or not the air is getting into the heads and, therefore, into the exhaust manifold and changing the level of oxygen the sensor reads.

Given that, we should run the appropriate hose from the diverter valve to the manifold at the back of the heads, the one that originally went there. And we could let the air that was to go to the exhaust pipe go back to the atmosphere. Seems like that should work. Right? The computer would see that the TAB & TAD solenoids work.

 

Theoretically Correct.

No, because then the computer would know as soon as it tried changing the air flow from the exaust to the cat when the engine warmed up that the O2 sensor didnt change readings as it should.

These things can be tricky.

 

Still struggling: The only diff from original would be that we wouldn't be injecting air into the cat. Instead, it would go into the atmosphere. So, when cold the air would go to the heads and the O2 sensor would see it. And, when the computer switched it to what it thought was the cat the air would instead go to the atmosphere. But, since the O2 sensor is ahead of where the air goes into the exhaust pipe the computer would still see that the oxygen level in the exhaust dropped and be happy.

 

Okay, I think 81' and Gary you guys might be misunderstanding each other. First, I don't know what the TAD and TAB solenoids are, but...I am fairly certain that there is a short hose coming off the diverter valve going to a long steel tube that goes to the cat. 81', that is the line that Gary and I are supposing can be let to atmosphere. We say this because there isn't a sensor or solenoid or anything we can think of that would "see" the fresh air in the exhaust past the O2 sensor. The o2 sensor only sees the fresh air coming in from the heads. Is there something we are missing?

Gary, I will have to figure out a way of reconnecting the diverter valve vacuum line, and the vacuum line going to that other diaphragm thingy right behiond the pump. When rebuilding the engine I burned those plastic vacuum lines shut because I didn't think I needed them anymore. So I need to cut the ends off to open the tubes back up and run a vacuum hose from there to the nipples on the components to get them to function properly.

 

Gary, you responded quicker than me! That's basically was I was trying to say also.

 

TAD: Thermactor Air Diverter valve control Solenoid and valve.
this alows the computer to divert the air to either the cats or the exaust manifolds.

TAB: Thermactor Air Bypass valve control solenoid and valve.
This alows the computer to bypass the air to the atmosphere.

I believe I did misunderstand him. I was thinking he wanted to just dump it to the exaust manifold all the time, that wouldn't work, or to dump it to the atmosphere all the time, that wouldnt work either.

If the air is pumped to the exaust, then you have it switched to atmosphere when it warmed up, I do not see this being a problem as it does this anyway at idle.

If you have it constantly dumping into the exaust, the computer would know. If you don't have it dumping into the exaust when it should, the computer would know. You can also hook it directly to the exaust pipe downstream of the O2 sensor. This is how these are hooked up with trucks without cats, but with air pumps.

I'm thinking you will be alright with that. Now if you had more than one O2 sensor, which is one reason why they added more later on, then it could tell coming and going.

Need a computer diagnostic before and after to see what all it needs. It could be a number of things compounded instead of just one outlying problem. I would look for a code 44 (Thermactor System) and/or possibly a Code 41 or 42 (Running lean or Rich) during the diagnostic, the way it sits.

 

Ray - Yes, let's put the bushings in tomorrow - at least the radius arm bushings. I doubt the leaf spring bushings are bad as mine weren't, although I did replace them.

81-F-150-Explorer - Sorry for the confusion. I didn't do a good job of explaining. But, do you know if the '82 AIR system is the same as the '86? Specifically, will Ray's wiring connect properly to my diverter valve? And, for that matter, will my relays plug in to his harness?

Also, how do we cause the 'puter to give us the codes? I have multimeters & test lights (awa ignition scope and lab scope) so we just need to know how to trigger it.

 

The diverter valve may be the same. There were several.

The wiring doesn't actually go to the diverter valve itself. It's controlled by vacuum. The TAD solenoid is bolted elsewhere on the engine. The vacuum line from the diverter valve plugs into the TAD solenoid. The TAB solenoid should be right next to it and may even be in the same bracket. The EGR solenoid looks simular and may be in the same area or with the other two.


This is going by memory so I might be missing something...

KOEO: Key on engine off test:

Start the truck and let it warm up to operating temps.

After it is warm, shut off and find the computer diagnostic and self test output connector in the engine compartment.

Self test input connector has a single white/Red stripe wire. We will call that [7].

Computer Diagnostic connector has a six wire connector but not all spaces will nessecerily be used. It could be a red or gray connector.

Hold the connector where the two spaces are up, and the remaining four are underneath.

/-[1]-[2]-\
[3][4][5][6]

Hook a jumper wire from #7 to #2.

Hook the voltimeter - terminal to #4.
Hook the voltimeter + terminal to the battery + terminal.

Turn the ignition switch to run and watch the needle. It will sweep.

A code 11 is passing. This is read by a sweep, then a another sweep.

A code 44 would look like... sweep / sweep / sweep / sweep / a pause / sweep / sweep / sweep / sweep

if another code is to be shown it will be followed by a short pause.

after all codes are shown, there will be a long pause then the codes will be repeated once.

Shut the ignition switch off: fix or inspect any problems found starting with the first code, then prepare for the KOER test.

Start the engine, the engine should rev up and sweep four sweeps for a V8 engine. ignore any little "blips" then after the truck idles down, there will be a single sweep. after this sweep push all the way down on the excelerator pedal and let off as quickly as you can. (on newer trucks there are even more proceedures)

After awhile the codes will begin to sweep. read them like you did with the KOEO test. after all codes are read, shut the engine off.

To delete the codes from memory, turn the ignition switch back to run and disconnect the jumper wire. If you do not want to delete the codes, remove the jumper wire with the ignition switch off.

Post the codes and I can decode them.

 

I might just try this right now....i'll be back in a minute or two...or more

 

Wow! Rep's for that help. Thanks.

Yes, I'd forgotten that the relays controlled the vacuum. IIRC, Ray doesn't have the relays mounted. But, I think I have two sets of them awa valve covers with brackets for them, so we can surely find a way to mount them even if we have to put the brackets on the inner fender.

 

Ford Fuel Injection » How To Run a Self-Test
Ford Ranger/Bronco II EEC-IV Testing

 

Okay, I jumped 7 and 2, hooked 4 to negative of voltmeter and positive to battery positive.

Turned the key on and here all sorts of clicking. Watched the meter and I got code 22, sweep sweep pause sweep sweep long pause, and then it repeated. Whats a code 22?

 

Gary, I have the entire AIR system still installed minus all the pipes and pump, I still have all the vacuum lines and solenoids on the passenger fender.