Hi guys my TPS sensor reads 0.75 volts at idle hot after rebuilding the carb so I need to adjust it. I see where the TPS plug is. What is a safe and easy way to drill it out, and what kind of adjuster will be under the plug to adjust it? Can I drill and adjust the TPS without removing the air horn or does it have to come off? I do have a full set of reverse twist drills if these will help at all.

 

327_TPI_77_Maro,
The plug can be removed without removing the airhorn. Those CCW drills would probably be perfect. I drilled a tiny hole (with a standard drill) and pulled the plug with a bent scribe.

Under the plug there will be a male 2mm Hex Head. You'll need a special 2mm female tool to turn it. I found my Rochester adjusting tools at Skywaytools.com. The kit, which includes two special wrenches, is about $18.

Here's a link to a photo of the tool(s) I uploaded a while back in another thread.


Here's the other thread...... it might have some additional info.
https://www.thirdgen.org/forums/carb...lp-please.html

Hope these helped.
Kurt

 

I normally never miss the opportunity to purchase additional tools, but I needed to adjust my TPS and found that a small roll pin lightly tapped over the end of the adjustment screw will work.

Also discovered that the spring under my TPS was weak and was allowing the entire TPS unit to move down into the bore when the plunger was depressed. Put another spring out of my spare carb parts box in there and everything's good. Played heck trying to figure that one out.

 

Thanks! I'll get this thing adjusted soon. I know the TPI cars "auto range" the TPS sensor within reason. Ie, every time you start the car it relearns what TPS reading is idle, and compensates accordingly. On a TPI car the TPS setting is not that critical unless it is way off because then the computer does not have enough room to scale from idle to WOT. Is the carb computer operating in the same way or does it not auto scale the TPS, ie, the higher the voltage the more timing it brings in no matter what, it expects 0.40 volts at idle no matter what?

 

Can't say definitively but based on empirical knowledge I'd say that the CCC expects 0.40 volts at idle. Good question though. I'll have to look into it.