Greetings,
Just rebuilt my CC Quadrajet on my 84 T/A. Car runs but it looks like I have a bad TPS now (no response to the voltage test and I got the CEL code 21).

So, I’m going to get a new TPS, but before I take the air horn off again, can someone explain what that little hook is on the underside of the air horn (photo attached)? It pivots on one end and comes down on the TPS. Didn’t think too much about it when I put the air horn on, but I think I might have installed it wrong and busted my TPS. Is the tip of the hook supposed to sit on the top of the TPS or along the side? Can’t find anything about this in my Haynes manual.

Thanks in advance and Happy Easter!

Steve

 

That's the visible end of the adjustment arm for the TPS. Up top there is a small plug behind which is a small screw that comes in at a ~90* angle and pushes down on that arm. The arm, in turn, pushes down on the BODY of the TPS sender (not on the plunger) which is spring-loaded to push up against that arm at all times.

So, as that arm is adjusted up or down via the adjustment screw that is who the TPS is adjusted.

If this is a quickie rebuild, don't even bother sweating over the TPS adjustment. It's absolute reading is relatively inconsequential (not hyper-critical to get it to read perfectly). On an EFI engine, TPS readings are very important. On a cc-QJet, not nearly as critical. As long as it's close (and it will be if it's still set at it's factory adjustment) and it changes proportionally with throttle opening, the ECM will accept it and be happy.

 

ah ha! Thanks so much - I think the arm got wedged into the side next to the TPS as I was putting the air horn on which would explain why the plunger didn't line up with the pin.

Thanks again!
Steve

 

Steve- yeah, that can EASILY happen. Putting these things back together and making all that stuff line up at the same time, it's best to have 3 hands.