Close



Results 1 to 9 of 9
  1. #1

    Default One more catalytic converters dilemma

    Hi everyone,
    After reading a ton of posts about the Thermactor and what controls it and
    Spending hours poring over the 1984 Ford Emissions shop manual I have come to the
    Conclusion….40 year old emission parts work about as well as nothing.
    I never read so much and learned so little,

    Now my problem, 2 years and 1300 miles ago, I replaced my 86-93 dual cats that I put on around 1993.
    They were rattling, so I brought a 2 Cat Catco H-Pipe and installed it.
    It has the air tube for the thermactor pump.

    I decided this week to check out my Air pump system and found…, nothing held Vacuum and forget about the TAD and TAB solenoids
    That according to the manual work off a timing controller/computer ???
    The diverter valve that sends Air either to the heads or cats was shot,the vacuum line’s were nothing more than a Vacuum leak,and was only directing air to the heads.

    I can’t even figure out how the dump valve works even though I found the vacuum solenoid on the drivers strut tower.., ya it still has its vacuum line and it’s plugged in…I mean how is it supposed to supply vacuum to the dump valve under load when there is no vacuum.

    So I rigged the air pump to send air directly to my Cats all the time. It is purely as simple as I could make to try and save my cats.
    No Vacuum lines anywhere… just air to the Catalytic converters.

    Will this be a problem… I know there are great minds on this site.
    Thanks,
    Scott
    84 GT 5.0L, T5, 8.8T-Lock, 5lug with 93 Cobra Brakes,
    MM RCL's,CC plates, Koni Reds, 17" Tri-Stars...CoilOvers next.

  2. #2
    FEP Senior Member
    Join Date
    Mar 2008
    Location
    darien il
    Posts
    530

    Default

    hi, emissions. the 85 carbed 302 is a really complicated emission control. the auto is different from the stick. i am guessing the 85 and 84 are near the same.

    the computer that you asked is behind the passenger kick panel. next there is more soleniods in the passenger fender (need to remove the inner fender).
    all of mine was cracked and needed to be replace or glued to to seal them up. also cracked vacum lines.

    the good new is that cats today are better than the 1985 and helped mine to pass emission.

    there is a diverter valve that will send air to the heads or the cats.

    try the search feature. there has been articles written on the 85 emissions which goes into great detail and far better knowledge than me.

    lastly remember that that this car was built before the fuel that we use ( in my state) was even made. E10 did not exist and does cause some problems with a carb.

  3. #3

    Default

    Thanks for your response,
    I am aware of the diverter valve , as that’s what started this whole problem.

    Anyway, I have been advised on another forum,not run air directly to the cats , as they might super heat and possibly cause a fire,
    I find this hard to believe, as my diverted valve was triggered by ported vacuum,

    So technically, it should be diverting air anytime you were moving.
    When I attached a vacuum gauge to vacuum line controlling the diverter valve, it only got a reading when the throttle was open.
    The diverter valve doesn’t work with a vacuum pump attached to it, so it’s toast.

    This is a factory 5spd car, so every control is analog .
    Just a bunch of vacuum lines and Tab/Tad solenoids, thermal temp switches.
    In other words, a lot of stuff.

    I was trying to simplify it so I won’t harm the catalytic converters.

    Anyone else with thoughts on this ?
    Thanks again,
    Scott
    84 GT 5.0L, T5, 8.8T-Lock, 5lug with 93 Cobra Brakes,
    MM RCL's,CC plates, Koni Reds, 17" Tri-Stars...CoilOvers next.

  4. #4

    Default

    Pull the smog equipment and run a catless mid pipe, if your state allows, would be my $.02
    "YEP, SITE'S BROKE"

  5. #5

    Default

    I would have done just that, but I spent $$ on the new Cats already.
    I guess if I clog up the converters, I can cut them out and replace them with a 21/4 pipe or clamp on SS braided flex lline.
    Scott
    84 GT 5.0L, T5, 8.8T-Lock, 5lug with 93 Cobra Brakes,
    MM RCL's,CC plates, Koni Reds, 17" Tri-Stars...CoilOvers next.

  6. #6
    FEP Senior Member
    Join Date
    Mar 2008
    Location
    darien il
    Posts
    530

    Default

    no need to cut them out. they actually do some good stuff. help stop the stinky smell, and lower emissions. if your car burns oil , then they will clog up. or if you are running rich they can turn red hot. (mine did that once). their is different class converters that have different standards. some need air others do not.

  7. #7

    Default

    Hi Bob85GT,
    I want to keep the he Cat’s…otherwise I would have sourced an off-road H-pipe.
    My plan at moment is to source another diverter valve and reinstall the factory routing.
    This should keep the air flowing into the heads at idle. At part throttle, the ported vacuum signal will then divert the air to the cats.
    This is the simplest way I can make the system work with out all the Tab/Tad vacuum/wires everywhere factory setup.
    In reality, this car is never driven in temperatures under 50 degrees, in fact, I rarely even use the manual choke. ( I run a 570 CFM Holley.)
    Now I have to figure out how the pump dump valve works at full throttle.

    I want to enjoy this car, as I have for the past 40yesrs and try to keep the smell/emsions at a minimum.

    Scott
    84 GT 5.0L, T5, 8.8T-Lock, 5lug with 93 Cobra Brakes,
    MM RCL's,CC plates, Koni Reds, 17" Tri-Stars...CoilOvers next.

  8. #8
    FEP Member 0F0 CBR's Avatar
    Join Date
    Feb 2019
    Location
    Ontario, Canada
    Posts
    123

    Default

    Hi, I have my smog pump running full time to my cats unless at high vacuum when off throttle. At high vacuum it dumps to atmosphere through the diverter valve as I have no ports in my cyl heads. BBK set up with air inlet in the middle of the cats. I do have a thread on what I did.
    http://vb.foureyedpride.com/showthre...d-Smog-Back-On

  9. #9

    Default

    OFO CBR,
    Thanks for the link of your write up.
    That’s a really nice setup you installed.
    My cats aren’t high dollar ones, just $250 Catco’s.
    21/4” pipes which is fine for my Engine. The rest of the system is a Dyno-Max cat back.

    Correct me if I’m wrong,
    But it seems that you are running the output of the Thermactor pump directly to the cats.
    Which makes some good sense, since the Diverter valve was only to send air to the heads during warm up.
    My diverter valve appears to be controlled by ported vacuum from the carb which in turn routed to a thermal switch on the intake.
    From there, it goes to the diverter valve.

    One would assume, that when ever the throttle was opened, air was directly sent to the cats, once the “ proper “ engine temperature was reached.

    Like your Mustang, it’s only driven in warm weather, so I was just thinking routing it directly as I think you have.
    I don’t see any benefit in buying a new diverter valve.

    My delima is the Thermactor Dump Valve.
    I don’t think it really needs to Dump Air for the 7-10 seconds I occasionally floor it.

    I still have to check its function, as it does hold a vacuum with a Vacuum pump .
    I am just not sure it’s doing anything just yet.

    Thanks for any input/advice.
    84 GT 5.0L, T5, 8.8T-Lock, 5lug with 93 Cobra Brakes,
    MM RCL's,CC plates, Koni Reds, 17" Tri-Stars...CoilOvers next.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •