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  • Code 21: TPS test procedure help. Paging Gerry!
  • Code 21: TPS test procedure help. Paging Gerry!
  • Code 21: TPS test procedure help. Paging Gerry!
  • Code 21: TPS test procedure help. Paging Gerry!

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  1. #16
    Code 21: TPS test procedure help. Paging Gerry! GerryLP's Avatar
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    Default Wow. Sorry for the hugely late replay

    Tatortot,

    I will send you my phone # over PM so that you can text me when you have an issue.

    Here are a couple of old images I had posted before.



    The troubleshooting chart is talking about the TPS connectors A,B, and C.

    GerryLP

  2. #17
    Code 21: TPS test procedure help. Paging Gerry! 22229stingray81's Avatar
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    Thanks Gerry!

    For those following along, I've decided to partially rebuild the carb. New TPS and accelerator pump for sure, and maybe even more if I'm feeling particularly brave. I'll report back when the work is done.

    -Tatortot
    22229th Vette in '81

  3. #18
    Code 21: TPS test procedure help. Paging Gerry! 22229stingray81's Avatar
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    Okay, I got the new TPS in, and it has been adjust to .56v. Also a new accelerator pump, and air horn gasket. It doesn't seem to have cured my problem, but the rough idle seems slightly better. I haven't done another fuel consumption test yet.

    I decided to keep looking for other vacuum leaks. I tested both front and rear choke pull offs, and the rear one is no longer working; it cannot hold vacuum. I've been searching for a replacement, but apparently the L-81 didn't come with a choke pull off? Can you L-81 owners confirm your carb does not have a rear choke pull off? Why would some one add one? Perhaps this isn't the stock carb?

    The vacuum line coming off the rear pull off goes to a Tee connector. One side is going in to the base of the carb at the rear, and the other has a very small hose or cable going into it that disappears into the firewall somewhere. I can get pictures if need be. The pic below is the only pic I had of the rear vacuum break handy.





    Last edited by 22229stingray81; 04-08-15 at 04:09 PM.
    22229th Vette in '81

  4. #19
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    [QUOTE=22229stingray81;1165570]I decided to keep looking for other vacuum leaks. I tested both front and rear choke pull offs, and the rear one is no longer working; it cannot hold vacuum. I've been searching for a replacement, but apparently the L-81 didn't come with a choke pull off? Can you L-81 owners confirm your carb does not have a rear choke pull off? Why would some one add one? Perhaps this isn't the stock carb?

    No Rear pull off on mine.
    I did think that your carb number looked a little odd (17081222). Nowhere i look has this listed as a carb for an 81 vette. What does your date code on it say? I'm thinking its not the stock carb.

  5. #20
    Code 21: TPS test procedure help. Paging Gerry! 22229stingray81's Avatar
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    Thanks Antz81; it's all FINALLY starting to make sense. It should be 17081228 for a non-CA automatic Corvette. Apparently 17081222 is off of 5.0L automatic Malibu, Impala, Caprice, El Camino/Caballaro, Camaro, Century, LeMans. UGH. I wonder what the differences are? And I wonder how much horsepower I've lost. Probably not much.

    Well, now we know I don't need the rear choke pull off. I have removed it, and the tee connector, and now I have that single cable/wire going straight into the back of the carb. Could someone tell me if this is remotely correct? And what the hell does that little cable go to? It terminates under a little metal box to the right of the wiper motor behind a relay. Also, I cannot remove the linkage without taking the choke housing completely off... so it's just hanging there for the time being.

    Before removal:



    After:



    Small cable terminates:

    22229th Vette in '81

  6. #21
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    Quote Originally Posted by 22229stingray81 View Post
    and now I have that single cable/wire going straight into the back of the carb. Could someone tell me if this is remotely correct? And what the hell does that little cable go to? It terminates under a little metal box to the right of the wiper motor behind a relay. Also, I cannot remove the linkage without taking the choke housing completely off... so it's just hanging there for the time being.
    That's a MAP sensor from memory. That's how it's connected on mine. I just have a different tube size. (Mine had been disconnected for no apparent reason)

  7. #22
    Code 21: TPS test procedure help. Paging Gerry! 22229stingray81's Avatar
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    Thanks!

    Quote Originally Posted by Antz81 View Post
    That's a MAP sensor from memory. That's how it's connected on mine. I just have a different tube size. (Mine had been disconnected for no apparent reason)
    22229th Vette in '81

  8. #23
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    Quote Originally Posted by 22229stingray81 View Post
    Thanks!
    I need thank you as well. Your posts reminded me that I hadn't checked my pull off for a vacuum leak. The pull of was fine but I suspect what was the original tube had perished but never been replace until now.

  9. #24
    Code 21: TPS test procedure help. Paging Gerry! 22229stingray81's Avatar
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    I found that the stainless steel tube going to the top tee connector (I think it links to the transmission??) was also leaking. The rubber piece connecting the manifold to the tube was original and completely perished. So that's replaced too. Next on the list is to take it for a test drive and see how it runs. We're getting there!
    22229th Vette in '81

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