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  1. #1
    FEP Power Member fgross2006's Avatar
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    Default troubelshooting code 46

    I have this code for a few weeks that I know of. Seems to be the only code present in KOER.

    Today I swapped out my ratty patched up negative battery cable for a repro correct one with the extra ground and the ECM ground connector. So as along as I had the hood up and it was a nice day here on Long Island I decided to take a shot at troubleshooting the code 46 I have.

    Since code 46 says no Thermactor bypass I checked the situation on the TAB. The first this I did was to pull the vacuum hose and placed my vacuum pump onto the nipple of the TAB and applied vacuum manually. Then i ran the KOER scan and low and behold no code 46. But now I have codes 21 and 41. Hmmm.

    I heard the engine kind of click when the ECM applied vacuum to the TAB. Since I had that hose off the TAB I heard it suck vacuum. I applied my vacuum gauge and it said 20. I then noticed the hose that goes to the TAB was flared they way rubber hose gets when it has been sitting in the same position a long time. apparently the original cream colored hard vacuum line is still there but the original connector is gone so a 4 inch piece of vacuum tube was slid onto it. I replaced the old vacuum tube with a new piece 1 size smaller so I could insure a snug fit.

    Since i verified the ECM was switching the solenoid on and vacuum was being applied to the TAB line, and since I verified no code 46 when I had manually applied vacuum I was sure the hose was leaking at the flare. No so. After connecting the tighter hose to the TAB, while the ECM was still pulling vacuum on that line, I still picked up code 46 doing another KOER but 21 and 41 went away.

    So I assume that when the TAB vacuum line was disconnected it was drawing air which explains the codes 41 and 21 showing up only when that line was not connected. But how is it possible that I still get code 46 when I felt vacuum pulling on that line and measured it with a vacuum gauge just before I reconnected it to the TAB? Especially since I verified there no code 46 when I apply vacuum manually?

    I have a spare, used TAD I can swap just to troubleshoot further, The one that's on the car was a NOS Motorcraft I installed around 4 years ago.

    Anybody have insight on this?
    Last edited by fgross2006; 06-23-2019 at 08:20 PM.

  2. #2

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    46 is the bypass right? Does that only turn on in certain circumstances like WOT? Can't remember.
    1984.5 G.T.350 5.0 CFI AOD Convertible (TRX package, loaded)
    Hooker Super Comp Shorty Equal Length Headers
    GT40 heads, Edelbrock 3721, K&N filter in stock dual snorkel,
    Comp cams XE254H, hypereutectic pistons, catted BBK H-pipe, full custom duals
    Maximum Motorsports caster/camber plates and strut tower brace
    3.73 rear. CS5 225/60/15 on 10 holes (street) Federal 595 rs-rr 225/45/15 on 10 holes (race)
    Everything else stock and fully functional.

  3. #3
    FEP Power Member fgross2006's Avatar
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    Default

    Quote Originally Posted by emerygt350 View Post
    46 is the bypass right? Does that only turn on in certain circumstances like WOT? Can't remember.
    I could be wrong but i think the thermactor dumps the air from the smog pump out the bottom of the unit, back into the atmosphere at WOT. The rest of the time its in bypass allowing the air to pass to the Thermatic Air Diverter.

    It makes no sense to me that the ECM sees the bypass working with manually applied vacuum, but when I apply the cars vacuum hose that has vacuum pulling through it, the code 46 comes right back up.

    I'm gonna try to swap out and put the original TAB back in. I tested it with a vacuum pump and the trap door inside does flip and the air does bypass. The scotchbrite filter at the bottom is filthy though and its not a serviceable item. I wonder if I can clean it with windex or de-greaser without harming the unit?

  4. #4

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    I would try. What harm could it do? Windex won't hurt the plastic.
    1984.5 G.T.350 5.0 CFI AOD Convertible (TRX package, loaded)
    Hooker Super Comp Shorty Equal Length Headers
    GT40 heads, Edelbrock 3721, K&N filter in stock dual snorkel,
    Comp cams XE254H, hypereutectic pistons, catted BBK H-pipe, full custom duals
    Maximum Motorsports caster/camber plates and strut tower brace
    3.73 rear. CS5 225/60/15 on 10 holes (street) Federal 595 rs-rr 225/45/15 on 10 holes (race)
    Everything else stock and fully functional.

  5. #5
    FEP Power Member fgross2006's Avatar
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    Default

    Looks like my suspicion was correct. The TAB was bad. Lucky I saved the original and it still works. I bench tested it with a vacuum gun and verified it dumps air out the bottom with no vacuum and lets air flow through the opposite tube when vacuum is applied. I checked the valve that came out of the car, which as a NOS Motorcraft i installed about 4 years back, and it doesn't dump air out the bottom whether there's vacuum or not. It flows right through.

    First I'm wondering how the ECM knows that when the TAB isn't a sensor with an electrical connection to the ECM. It has a vacuum hose. Does anyone know specifically how the EMC learns of a no air bypass condition when it doesnt get an electrical signal from the TAB?

    Second, I wonder if there's a way to free up whatever's stuck in the TAB. When i apply vacuum I can see the trap door inside lift and drop when I release the vacuum. So if the valve internally is functioning why wont air "bypass" and dump out the bottom of the TAB?
    Last edited by fgross2006; 06-25-2019 at 05:10 PM.

  6. #6

    Default

    interesting. I bet it is just whatever 'seals' is either rotten or gunked up. Maybe a good soak in penetrating fluid? even better would be sonicator.

    What did you end up doing for a smog pump? My 1 year old cardone is squealing under acceleration and it is not making me happy. So close to just getting the idler and disconnecting the whole thing (only have down stream) but I don't want the cats to die or the exhaust to kill small birds.
    1984.5 G.T.350 5.0 CFI AOD Convertible (TRX package, loaded)
    Hooker Super Comp Shorty Equal Length Headers
    GT40 heads, Edelbrock 3721, K&N filter in stock dual snorkel,
    Comp cams XE254H, hypereutectic pistons, catted BBK H-pipe, full custom duals
    Maximum Motorsports caster/camber plates and strut tower brace
    3.73 rear. CS5 225/60/15 on 10 holes (street) Federal 595 rs-rr 225/45/15 on 10 holes (race)
    Everything else stock and fully functional.

  7. #7
    FEP Power Member fgross2006's Avatar
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    Default

    Quote Originally Posted by emerygt350 View Post
    interesting. I bet it is just whatever 'seals' is either rotten or gunked up. Maybe a good soak in penetrating fluid? even better would be sonicator.

    What did you end up doing for a smog pump? My 1 year old cardone is squealing under acceleration and it is not making me happy. So close to just getting the idler and disconnecting the whole thing (only have down stream) but I don't want the cats to die or the exhaust to kill small birds.
    I got lucky with the smog pump. The regional manager from Autozone found one and swapped out mine. But if I had to do this again I'd go for a NOS Motorcraft instead of cardone junk pumps. Look on ebay and the motorcraft originals go for around 100 bucks. The cardones are being sold for 250 - to 300. its absurd.

  8. #8

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    is 32-291 the right number to look for with the motorcraft or is that only a cardone version? Can't see any motorcraft pumps when I ebay it.
    1984.5 G.T.350 5.0 CFI AOD Convertible (TRX package, loaded)
    Hooker Super Comp Shorty Equal Length Headers
    GT40 heads, Edelbrock 3721, K&N filter in stock dual snorkel,
    Comp cams XE254H, hypereutectic pistons, catted BBK H-pipe, full custom duals
    Maximum Motorsports caster/camber plates and strut tower brace
    3.73 rear. CS5 225/60/15 on 10 holes (street) Federal 595 rs-rr 225/45/15 on 10 holes (race)
    Everything else stock and fully functional.

  9. #9

    Default

    I see on rockauto they list everything and its grandmother as a ford number...D8BZ9A486A, E0TZ9A486F, E1AZ9A486A, E1TZ9A486A, E1UZ9A486A, E1ZZ9A486H, E1ZZ9A486L, E2SZ9A486A, E2TZ9A486B, E3SZ9A486C, E3TZ9A486B, E3ZZ9A486E, E4AZ9A486A, E5AZ9A486A, E6VZ9A486A, E75Z9A486A, E7SZ9A486B, E8ZZ9A486B

    Is that true and what is the real CX-XXX number I should look for? Is the different just going to be the snorkel?
    1984.5 G.T.350 5.0 CFI AOD Convertible (TRX package, loaded)
    Hooker Super Comp Shorty Equal Length Headers
    GT40 heads, Edelbrock 3721, K&N filter in stock dual snorkel,
    Comp cams XE254H, hypereutectic pistons, catted BBK H-pipe, full custom duals
    Maximum Motorsports caster/camber plates and strut tower brace
    3.73 rear. CS5 225/60/15 on 10 holes (street) Federal 595 rs-rr 225/45/15 on 10 holes (race)
    Everything else stock and fully functional.

  10. #10
    FEP Power Member fgross2006's Avatar
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    Default

    Quote Originally Posted by emerygt350 View Post
    I see on rockauto they list everything and its grandmother as a ford number...D8BZ9A486A, E0TZ9A486F, E1AZ9A486A, E1TZ9A486A, E1UZ9A486A, E1ZZ9A486H, E1ZZ9A486L, E2SZ9A486A, E2TZ9A486B, E3SZ9A486C, E3TZ9A486B, E3ZZ9A486E, E4AZ9A486A, E5AZ9A486A, E6VZ9A486A, E75Z9A486A, E7SZ9A486B, E8ZZ9A486B

    Is that true and what is the real CX-XXX number I should look for? Is the different just going to be the snorkel?
    I cant vouch for this being 100% correct. but on ebay its listed for 84 Ranger which is a tiny pickup truck. If I was in a pinch and needed the part I'd try this one. https://www.ebay.com/itm/NEW-GENUINE...6/182554201738

  11. #11

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    Is that the model you put on yours? If it works, I could care less. I assume they are all rated the same pounds or whatever. I see some are 31 and that one is 16 lbs per hour. That could be the only issue if it fits.
    1984.5 G.T.350 5.0 CFI AOD Convertible (TRX package, loaded)
    Hooker Super Comp Shorty Equal Length Headers
    GT40 heads, Edelbrock 3721, K&N filter in stock dual snorkel,
    Comp cams XE254H, hypereutectic pistons, catted BBK H-pipe, full custom duals
    Maximum Motorsports caster/camber plates and strut tower brace
    3.73 rear. CS5 225/60/15 on 10 holes (street) Federal 595 rs-rr 225/45/15 on 10 holes (race)
    Everything else stock and fully functional.

  12. #12
    FEP Power Member fgross2006's Avatar
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    Default

    Quote Originally Posted by emerygt350 View Post
    Is that the model you put on yours? If it works, I could care less. I assume they are all rated the same pounds or whatever. I see some are 31 and that one is 16 lbs per hour. That could be the only issue if it fits.
    No I got a replacement of the Cardone from Autozone so thats what I have installed. If the cardone fails again I will go with a NOS Motorcraft. The seems to be plenty of them on ebay and for whatever reason the cardones are no longer in stock at any parts dealer so the price went up beyond normal

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