Need a good TuneUp Tech Guide for Thermoquad

Fuel and Air Systems

  1. shg340

    shg340 Well-Known Member

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    I got the TQ on the Duster this afternoon and now I've got some hesitation when accelerarting and considerable Bog down when I kick it. Can't tell if its flooding or lacking fuel. Anyone know of a good tuning guide that I could pull off the web to get this thing going correctly. It needs to be pretty specific as I'm not your best engine or tech guru. Anyone have any suggestion or links they could share I'd apprecvaite it? Thanks...
     
  2. six pack

    six pack Well-Known Member

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    make sure the air door is adjusted properly, if it bogs you may have to increase spring tension. If when the engine is off you should be able to manually push down on the secondary air door, if you can't someone bent the wrong linkage trying to adjust the choke vacuum break.
    Get an overhaul kit, that should have all the adjustments and specs.
     
  3. dave571

    dave571 Well-Known Member

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    demonsizzler is a tq guru.

    He had a membership on the old board, but I haven't seen him here yet.
    I think this is a current email addy for him. demonsizzler1@cswebmail.com

    He does have a board somewhere too. Very knowledgeable and friendly

    Personally, I feel the first step to tuning a 25 year old smog carburator is removal.
    Step 2 find garbage can, and attempt long distance toss. Can be made into a game for the whole family.
    Step 3, buy something that has had at least some updates since the introduction of the cassete tape, :afro: and doesn't have a center section made of plastic. :puker:

    Those are just my thoughts, no offense...LOL 8)

    I can't be flaming you, because I used to have a duster that looked alot like that, but mine was a 73 340 duster. I loved that car. :salut:
     
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    • shg340

      shg340 Well-Known Member

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      Yea, I somewhat agree. this was an awesome carb 33 years ago when it was new. Really kicked axx on those gm small blocks. I debated whether or not to put it back on, so I had Demonsizzler rebuild it for. It has been updated, I just haven't been able to get in touch with him in the past few days to discuss the engines problems after putting her back on the motor. I'm hoping its something simple to correct for she fires right up and idles good, etc, just has that hesitation at low rpm's and too much lalg when kicked in full throttle. I know the old TQ had a heck of a secondary lag when she kicked in, but this is a bit much.
       
    • demon sizzler

      demon sizzler Well-Known Member

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      It still is an excellent carb. When I worked for Bary Grant, there were literally hundreds of brand new defective carbs at any given time; anything from real loose throttle shaft to bore fitment to metal shavings in the metering block and float bowls to loose boosters and throttle levers. The same things happen to Holleys and Edelbrocks too. I have sent you 2 more emails asking you for specific info. Without this info/feedback from you, I cannot even begain to know what is going on with the carb or if you have other issues. I have every intention of helping you get your engine running right; it's my job. There are many people that I have built these carbs for that really are happy with them. If you can go through and answer the questions I posed about your carb, I can help solve the problem, thanks, DAVID.
       
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      • shg340

        shg340 Well-Known Member

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        Demonsizzler, I responded to your e-mails late this afternoon. Hopefully I've passed along what you need to formualte a remdy for my problem.

        Just respond to the email address on my notes and we can use that media to work through this. Thanks...
         
      • chad72duster

        chad72duster Well-Known Member

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        man he sounded pissed :shock: :shock: Im with david through that tyhing in the trunk and get you a holley or demon and stick it on for just for shows when you want it all orginal. Call Jessie over at Bigs he will hook you up Steve :D
         
      • shg340

        shg340 Well-Known Member

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        Chad, Yea, I've got a Buddy who has a Demon that has offered to let me use it to see if it makes a difference. Demonsizzler has been very helpful though and is trying to help figure out what is going on with my TQ. Its just hard to communicate via e-mail very effectively and especially diagnois an engine problem.

        But your right, I think he might have been a little PO'd but we're on the same page now.

        How's the car coming man. got her fired up and rippin gup pavement yet?
         
      • cuda66273

        cuda66273 Well-Known Member

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        Interesting comment, we have sold 1.4 Demon carburetors per working day this year. We disassemble each carburetor and inspect it for any of the above mentioned oversights in the manufacturing process. About 1 in 6 has some small problem that we have to adjust or repair, usually bent linkage from abusive shipping, sometimes we'll find a jet loose or a screw that didn't get tightened but with all the Demons we have sold, serviced and tuned over the last 10 years I can only recall one King Demon that actually had a manufacturing problem that was more than a simple repair or adjustment and had to be returned to factory for repair.

        The honest truth is "Nothing is a bolt on" everything you buy needs to be repaired, clearanced, checked for defects or modified to fit or work correctly. Anyone who buys a carburetor from Sizzler, Barry Grant, Edeljunk or even Biggs don't think for one second that it's ready to run on your car. Check everything and when your sure it's correct then bolt it on and begin the correct tuning proceedure.

        I have had many discussions with the Tech people and Management at BG and we have had many chuckles over the reasons why people return carbs as "Defective" I would guess that 90% of returns are not defective product but defective owners. They order the wrong carb series or size and return it as defective, they are too stupid to own a carburetor or a performance car and send back the carb. I get 20 tech calls a week from people who bought their carbs from another source and they can't get them tuned most of the problems they describe are not a carb issue.

        They try and run timing in the motor based on the fender tag for a /6 on their new 440 (6*) and they think that the timing is relative to the car not the motor.

        Piss poor combinations that a computerized fuel injection system couldn't make run.

        Don't know a 4 corner bleed from an Idle speed screw.

        850 carbs on small blocks

        750 Mighty Demons on near stock motors.

        Vacuum carbs on 2600# cars with 4.30 gears and a 5 speed tranny or better yet the most recent.....same combo with a 4200 stall in a 3000# all out race car.

        Mechanical carbs on a 4000# B body with a 2.73 gear and a stock convertor with a 318.

        Over Carbed, over cammed, wrong series, no thouht into combination, inability to tune it, no timing in the motor, poor combination built from a Summit catalog, Engine builders working on tune-up, asking 10 freinds to tune it and just general customer stupidity is the cause for most returns.

        I just wish I could get my hands on those returned carbs, I'll bet that 90% or more could be fixed without replacing a part and be fixed in 30 minutes or less with simple baselining and general inspection.

        I could go on forever describing "Bolt-On" parts and the problems we encounter from valve train components, pistons, chassis parts to valve covers and intakes. Take nothing for granted it'll bite you in the ass everytime.

        Concours Show Car...have Sizzler fix you up
        If you want Power and Reliability...call Us, we'll get you dialed.
         
      • 71Duster

        71Duster Well-Known Member

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        I can second Don's remarks there, When I got my Demon on and rolling the only issues I had with tuneing where 90% of the cars issues not the carbs. That Demon is so sensative that little problems the previous POS carb masked suddenly come out loud and clear but once its Dialed in the things got throttle response like EFI. Since we are talking carbs I should ask a question about myy Speed Demon Don. When its cold it fires right up great, when its hot and I shut it off for no more then 5mins it'll fire up on a half crank, when its soaks a little usually foot to the floor to start. Any idea what I've done wrong? Wish they'd teach us carbs in school still. All EFI now.
         
      • cuda66273

        cuda66273 Well-Known Member

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        Your float may be set a tad high and you may be getting a bit of siphoning on shut down when the temp spikes.

        Are you running one or more of our Aramid Fiber 4 hole gaskets?

        Gotta run, I'm on a thrash to get to big race in Canada, Fish needs allot of tuning and maint.

        Later dudes and dudettes see ya on the silver screen

        Check the back window on the Fish as I pull into the burnout box
         
      • 71Duster

        71Duster Well-Known Member

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        Just the single gasket that you sent, The float levels are dead on from where you set them, I haven't checked to see after it gets a good heat sink but I'll watch next time. -its damn cold out today so much for summer-
         
      • demonwiese

        demonwiese Well-Known Member

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        I sure love the sound of a well tuned TQ 4's opening up! Have to admit I wish I knew all the secrets behind that monster too. To the average guy they are hard to tune. But when they are, look out ! I know mopar magazines have had articles on this topic. Wish I would have saved that issue!
         
      • shg340

        shg340 Well-Known Member

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        Demonweise, I agree. when the TQ is set up correctly, it was an awesome carb. When those secondaries opened up, there was no doubt what was happening.

        I finally changed out my TQ since it never right after rebuilding. My hesitation problem was due to an accelarator pump problem and that was corrected, but it still has some throttle linkgeage problems as well. Demonsizzler did what he could for my carb and I feel he did a good job given what he had to work with. No problems or issues from me. When I had a chance to swap it out for a Holley, I tried it and wow, the difference was amazing. I'mm keeping the TQ for shows, but for regualr street driving, I'm running the Holley.
         
      • joseph lamb

        joseph lamb Active Member

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        Yeah , that is why Chrysler Corp used the TQ for 15 years and Carter copied the Quadrajet , which I would guess you also think is an boat anchor !!! All my friends run FI and have nothing but tuning and starting problems . If their cars will even run at all . Love the TQ and the QJET !
         
      • rumblefish360

        rumblefish360 So close, yet so far away FABO Gold Member

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        Did you realized you dug up an old thread from ‘04 & told a guy off that hasn’t been here since 2010?
        :rofl:

         
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        • joseph lamb

          joseph lamb Active Member

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          yeah I did actually figure that out , was hoping YOU WOULD NOT SAY ANYTHING...but
           
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          • joseph lamb

            joseph lamb Active Member

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          • joseph lamb

            joseph lamb Active Member

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            and just to let you know my THERMOQUAD is working PERFECTLY TODAY ..ha
             
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            • rumblefish360

              rumblefish360 So close, yet so far away FABO Gold Member

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              :rofl:
              It’s all good...
              I can’t wait till I bolt mine down and give it a whirl. I have a new one sitting for quit sometime now just waiting...
               
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              • MoparMike1974

                MoparMike1974 FABO Gold Member FABO Gold Member

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                I believe I have a thermoquad tune guide in pdf format on my computer at home. It may have been written by demon sizzler. This would have been about 15 years ago. I will see if I can dig it up.
                 
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                • joseph lamb

                  joseph lamb Active Member

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                  See if you can , I plan on doing alot more of these old Thermoquads , this one I just finished is running really great on this 340 DUSTER and I used the WALKER rebuild kit from NINJA , so happy I did !!..Advanced Auto Parts kit was junk , the Quad rings swelled up 100 ths in three days , UGH ,,Thanks for all the help on this project 72 Duster 1 owner 340 , speed SURVIVOR....
                   
                • Tom Over

                  Tom Over 2nd generation Mopar nut

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                  Hi Joseph, I also could use a good rebuild guide for the TQ! Got a rebuild kit from Walker but the instructions are missing! Thank you for any help you can give!!! Tom Over
                   
                • rumblefish360

                  rumblefish360 So close, yet so far away FABO Gold Member

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                  @Tom Over FWIW, there is a very good book to have on hand for all Carter and Edelbrock AFB/AVS carbs as well as the TQ and the WCFB. It’s been around for decades. IIRC, it is a SA Design book. They have instructions and exploded views. While not model specific, just general, it will show you the way in a step by step process.
                   
                • Tom Over

                  Tom Over 2nd generation Mopar nut

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                  Thank’s for that info, rumblefish360! I’m going to check it out today!!!
                   
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