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Discussion Starter #1
I am in the middle of replacing the Thermactor Valve and Check valves on my 87 302 Bronco.

For the life of me, I cannot get off the check valve from the tube that runs down to the cat. It looks as it the u-bolt was over tightened. It will spin, but that is about it.



So, any ideas of getting it off? I have tried heat, channel locks, a hammer (kind of)...

How important is it? I know what it is supposed to do. When I run the engine I can feel a little pulse from the tube, but mostly a slight draw (venturi effect).

Also to confirm, the check valve on the crossover tube and thermactor valve are shot, I can blow air in any tube, in any direction, and it comes out all the other tubes with or without vacuum.

Lastly, with the engine running and the cross over tube off, should there be any pressure or suction at the hole in the back of the heads? I am not getting much of anything.

Thanks
 

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I ended up destroying the tube trying to get mine off and ended up replacing it. Also replaced the soft line going down to the cat.
IIRC your O2 sensor is down-exhaust of that and expects it to be operating correctly. If it's not there, I *think* it'll read too rich and lean out your engine trying to compensate. (or, alternatively, if it's always open, it might read too lean and try to richen your engine?)
 

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Discussion Starter #3
Replaced the soft line going to the cat? Mine is a hardline, to which this is stuck on top.

My O2 sensor is upstream of that. This dumps straight in front of the cat (used to dump directly into the cat). This makes sense as when cold the air is pumped into the heads which would lean out the readings at the O2 sensor and make the truck run richer (same results as a choke). Once warm the air is pumped to the cat to help with NOx (supposedly).

Anyone have to cut the tube short and run a small rubber tube to the top of the tube that runs to the cat to this check valve?

Repeat:
Also to confirm, the check valve on the crossover tube and thermactor valve are shot, I can blow air in any tube, in any direction, and it comes out all the other tubes with or without vacuum.

Lastly, with the engine running and the cross over tube off, should there be any pressure or suction at the hole in the back of the heads? I am not getting much of anything.
 

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Yo slawson2000,
Some members have used high temperature silicone hose.

RacerX did it

But it turned out that "...Bassani made a mistake when they ordered bulk hose from Purosil (The manufacturer of the hose) and got the wrong type in..." by BRBuzz151


Obtain the hose from http://www.pciinc.com/shop-pci/!/SILICONE-HOSE/c/16340029/offset=0&sort=normal
Very good customer service and probably provides to NAPA etc.
 

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Discussion Starter #5
That looks like it will work, especially because my issue is at the other end of the tube. Thanks.

For the time being (until I can get parts ordered/delivered/through the holidays etc.), I think I will just plug the heads and vacuum line and run a hose from the air pump to the stuck check valve. Anyone see any issues with that?

Repeat (still would like an answer)
Also to confirm, the check valve on the crossover tube and thermactor valve are shot, I can blow air in any tube, in any direction, and it comes out all the other tubes with or without vacuum.

Lastly, with the engine running and the cross over tube off, should there be any pressure or suction at the hole in the back of the heads? I am not getting much of anything.
 

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Wish I could help but I never ran the engine without mine connected. I did a write up a few years back on removing and installing them. Maybe if you find the write up it would help you.
 

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Discussion Starter #8
I appreciate the response. In looking into it further (at least with internet info), the thermactor valve and check valves are shot - completely. Adding vacuum should alter the direction of flow and the check valves should operate only one way.

I just hooked up the air pump directly to the tube to the cat with some heater hose, I will upgrade that to some high temp when I have time. I left in the check valve I could not get out. The air bypass is still upstream although I really do not see what it offers as a benefit.

Also it seems that feeding air directly into the cat is where it goes most of the time anyway, so no harm there. Just did a 600mi road trip, no CEL, no drivability issues. As far as I can tell no negative effects on the engine.

I cleaned out the holes in the back of the head. I did find that after cleaning out the holes in the back of the heads with a little carb cleaner and a wire brush that I had inserts in the hole that stepped down the 5/8" plug to I think a 7/16-14. Odd I thought they were just caked over.

At idle not getting any vacuum or pressure out of those holes. I still would like to know if that is normal...
 

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Discussion Starter #9
Well, update.

The CEL came on and indicating Code 95 after about 700mi, I guess my bypass is not working. I find this odd as, at the moment, there is no thermactor valve in the truck and the heads are blocked off. What would trigger this? The only sensor effected (as far as I can tell) is the O2 sensor and the air is pumped in the exhaust after the sensor. What would trigger this code?

Unless... In my book code 95 also is a Fuel Pump Monitor Signal. I do not think these things have such a thing, but maybe I am wrong. I did find that I have a failing fuel pressure regulator (fuel leaking into the vacuum line). I guess I should fix that first.
 

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why dont you just replace all the broken stuff?

Check with pollutioncontrol2
they have most all the emissions valves and such. anything they dont have you will have to find in the junk yard or on ebay.
 

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Yo Slawson,
DTC 87, 95 & 96; "...These codes relate to low or no power reaching the fuel pump. Start testing at the fuel pump relay. The relay must respond to the EEC processor and the relay contacts must be a low resistance path for fuel pump power. Relay testing can be done in a couple minutes with the fuel pump test table. Fuel pump relay testing;
1. Use solenoid test at EEC pin 22 to check relay coil current draw.
2. Voltage at pump power terminal must be within .5v of battery power when relay is turned on with amp meter at pin 22.
Check power from battery if voltage is low.
Check the inertia switch and fuse if battery voltage is missing.
Pin 22- (light blue-orange) Grounded to turn "on". Voltage will drop to about 1v when "on". Current draw will be 160 to 270mA Pin 8- fuel pump monitor (dark green-yellow) 0v engine off, battery voltage with engine running..." by Dustin S

DTC 95 KOEO & CM, Fuel pump secondary circuit failure. The EEC senses infinite resistance to ground from the fuel pump on the Fuel Pump Monitor circuit. Bad ground or always on. Possible bad fuel pump ground or open between fuel pump and pin 8 at PCM

Inspect;
inertia switch
FP relay or it's connector, harness,
inspect ground G701 Behind IP near RH side of radio

Wiring Diagram
 

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Discussion Starter #12
Thanks both.

J,
That it the eventual goal. But..... I took it apart to originally to replace the thermactor as from blowing in it, it is shot (see above). Local stores said they had it, then it was 1 day, 3 days, etc. I also found the check valves to be bad. One check valve I could not get off (as shown above) and is still there. So I had to get it together as it is my daily. I figured I could try and see how the emissions junk worked because I am contemplating GT40 heads at some point. I have read so many different results of removing the smog stuff, changing to GT40 heads with and without ports, what tossed a light, what tossed a code, when air from the pump was going to what part of the engine, what triggered what, etc. that I wanted to know basically what effected what so see what kind of heads I need to source. So I did what I did to get back on the road.

M, I agree that it maybe fuel related.

I found Code 95 (depending on where you go and what you read) can be a number of things.

95 (KOEO) Fuel pump: open, bad ground or always on.
95 (KOEO) AIR not Diverting (AIRD).
95 (Mem) Possible bad fuel pump ground or open between fuel pump and pin 8 at PCM (Fuel Pump Monitor signal). Power/Fuel Pump Circuits
95 (KOEO) Thermactor Air System problem - right (passenger) side air flow always upstream.
95 (KOEO) Fuel Pump Monitor (FPM) signal - indicates circuit problem).

There may be other variants. Based on this, it may be fuel related...

I checked the pressure. 40psi KOEO, Turn key off and is sinks to about 20-psi. 30psi running. I think this also indicates a bad regulator in addition to the fuel coming out of the vacuum port.
When tracking down a problem, I always start with the known issues and work into it...
I doubt the regulator is the whole problem, but it surely could be part....

Also I do not have an amp meter. What about a voltage check?
 

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Discussion Starter #14
I have a few multi-meters, but as far an amp setting, it only has one, 10A. I am not sure it will read down to the levels required.

Amps is not my strongest suit.

How do you access pin 22 with the harness connected? Do you check it with it detached? Check it at the relay? Amp meter is used in line, correct?

I know the pumps are at least working as the truck runs fine outside of a hot start issue (takes 2 or 3 attempts to start or will start on the first time if the throttle is feathered). Could it be a failing relay?
 

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Yo slawson2000,
Since Pump runs, ignore test by Dustin S.
Replace FPR because it's diaphragm is damaged.

That is all I could find on DTC 95.
Fuel Injection Technical Library » Two Digit Codes 75-99

& DTC 95 Fuel pump secondary circuit failure. @ http://www.freeautomechanic.com/diagnostictroblecodes7.html

DTC 95 Test @ http://www.fullsizebronco.com/forum/5896562-post11.html
Includes; DTC 95 KOEO & CM, Fuel pump secondary circuit failure. The EEC senses infinite resistance to ground from the fuel pump on the Fuel Pump Monitor circuit. Bad ground or always on. Possible bad fuel pump ground or open between fuel pump and pin 8 at PCM by miesk5
 

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Discussion Starter #16
I know I have two pumps. I know the high pressure on the rail is working otherwise it would not run (I have replaced it a couple times). Maybe an issue with the tank pump?
 

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When trying to separate metal parts, heat is usually a good remedy.....:doh0715:.....

I remember when I first bought my 86, the thermactor had rusted thru and not being experienced as I am today....lol lol....it took me some time to figure it out, it was throwing codes and then engine felt like it was missing and power range was low a real PITA. A bad thermactor with a hole in it actually causes an "exhaust leak" in the emissions system, cost around $20.00 and I'm still good to go......lol lol...


Good Luck ~ :thumbup
 

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Discussion Starter #18
JK,
I took the blue wrench to it and got that stupid thing glowing. No avail. At some point the clamp got tightened too much and the tube is indented. It will spin, just not come up. Had a big ole open end wrench under it and was whacking it with a hammer best I could with a friend holding it from underneath. Nope. It looks as if I may need to trim a little off the top and run a short silicone high temp piece of tube to make the connection. I know I replaced the thermactor about 115k ago... but I remember, I could not get that check valve out back then either.

The new fuel regulator is in. Had the battery disconnected. Gone is the hard hot start... oh so nice. No super rich starts either. Yeah baby.

However, the CEL did pop on. Pulled codes. KOEO, still 85 and 95. The 85 I have always has since I have a MAF conversion from FMS, uses a later Mustang computer and the Mustangs have a Canister Purge solenoid, my Bronco does not. 95 was in permanent memory. Odd I thought for only running for 5 min. KOER, 94 and 44, which makes some sense as the thermactor is currently out of the truck. The timing is right at a steady 11 (I did the SixLiter not too long ago). Idle bounced about 300 rpms with the spout out. Steady with it back in. Vacuum steady 18 at idle.

I have a couple big capacitors for the stereo. I wonder if that allowed the codes to remain. I thought I had cleared them by removing the single wire from the reader as soon as the KOEO codes started. Is that right? I am a little rusty...

By the time the tests were complete the CEL was off. Time will tell. Glad I am doing this now instead of after some GT40 heads without a AIR port and I was having all these problems.

While I am at it, How do you test the blowoff/diverter (?) valve just behind the AIR pump? I am assuming with vacuum air should pass through toward the thermactor valve and without vacuum the should just blow out of the valve somewhere. Is that right?
 

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Yo,
How to Clear Keep Alive Memory (KAM)
The PCM stores information about vehicle operating conditions and uses this information to compensate for component tolerances. When an emission related component is replaced, Keep Alive Memory (KAM) should be cleared to erase the information stored by the PCM from the original component.
To clear KAM: Disconnect the negative side of the battery for a minimum of five minutes.
After KAM has been cleared, the vehicle may exhibit certain driveability concerns. It will be necessary to drive the vehicle 10 miles or more to allow the processor to relearn values for optimum driveability and performance. (Distance is dependent on the vehicle application.)
...

OK, I BELIEVE we're yakking about the Thermactor Air Bypass (TAB) Bypass Valve.
Here is the TAB VALVE PIC by SeattleFSB (Seattle FSB)


Normally Closed Air Bypass Valve Functional Test; "...1.Disconnect the air supply hose at the valve.2.Run the engine to normal operating temperature.3.Disconnect the vacuum line and make sure vacuum is present. If no vacuum is present, remove or bypass any restrictors or delay valves in the vacuum line. 4.Run the engine at 1500 rpm with the vacuum line connected. Air pump supply air should be heard and felt at the valve outlet.5.With the engine still at 1500 rpm, disconnect the vacuum line. Air at the outlet should shut off or dramatically decrease. Air pump supply air should now be felt or heard at the silencer ports.6.If the valve doesn't pass each of these tests, replace it...."
Source: by Chilton

Normally Open Air Bypass Valve Functional Test; "...1.Disconnect the air supply hose at the valve. 2.Run the engine to normal operating temperature. 3.Disconnect the vacuum lines from the valve. 4.Run the engine at 1500 rpm with the vacuum lines disconnected. Air pump supply air should be heard and felt at the valve outlet. 5.Shut off the engine. Using a spare length of vacuum hose, connect the vacuum nipple of the valve to direct manifold vacuum. 6.Run the engine at 1500 rpm. Air at the outlet should shut off or dramatically decrease. Air pump supply air should now be felt or heard at the silencer ports. 7.With the engine still in this mode, cap the vacuum vent. Accelerate the engine to 2,000 rpm and suddenly release the throttle. A momentary interruption of air pump supply air should be felt at the valve outlet. 8.If the valve doesn't pass each of these tests, replace it. Reconnect all lines..."
Source: by Chilton



Thermactor Air Diverter Solenoid (TAD, AIRD, AM2); "...is controlled by the EEC-IV computer and provides vacuum to the Air Bypass/Air Control Valve. With vacuum present, air flows to the exhaust manifold. With no vacuum, air flows from the air pump to the catalyst..."
Source: by Ted F

Test; Key off. Disconnect both AIRB/AIRD solenoid connectors and measure both solenoid resistances. Each resistance should be between 50 and 100 ohms.
 

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Discussion Starter #20
Maybe my capacitors are keeping my KAM, alive. Had it disconnected for longer than that. Still there.

Nope... My themactor valve and check valves are toast. Had them out and with or without vacuum, blowing in one of the three 3/4" openings, blew out the other two. I know this it the one at the back of the block.

The one I can talking about is in this picture just behind the AIR pump. One hose in, one hose out and a vacuum line. I think it acts like a blow off/diverter That is the one in questions.
 

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