American Power

What is the effect of tuning the TPS? If it is in the the accepted values then if larger angles were used how would it affect the performance and the fueling of the tpi?

rgarcia63

A larger angle would require an increase in maximum TPS voltage, any increase above 5 voltage would cause an error and I think probably put it into Limp Home Mode, not sure what the ECM's response would be.

American Power

Thanks for the info. I have it currently at a 45 degree angle pointing downward and this caused the revs to go down by 3-400 rpm. Is this correct? I see a lot of TPSs pointing at a level position so am I at a possibly damaging setting? I want to know how to get the best performance setting for the TPS without damaging anything and remaining stock.

305sbc

iTrader: (3)

Do a search on setting the TPS.
There should be a write-up and explaination of the test equipment you would need.

You set it by voltage. I use a DMM and then verify with a scan-tool.

rgarcia63

I thought you were just trying to get a better resolution, but on my 88 it's as said set by voltage between .5 an .6vdc later model are non-adjustable. The minimum air rate which needs to be set as stated in the tech article referred to above will use that voltage as a base reference for idle.

chevelle600

iTrader: (9)

i have to tune by my tps, my motor just doesnt want to have a nice idle, but for me, i notice a difference in the shift points. but i also noticed when you mess with it too much, you get surging, and the idle tends to drop really low at stop lights almost to the stalling pont.

American Power

Thanks for all the info. I just got my car painted at Maaco and i will be driving it home tonight where I will tune the TPS to its proper setting.

rgarcia63

Please do the minimum air rate procedure first this will place the throttle blades where it will idle at the recommended rpm. If it doesn't need adjusting then you can set the TPS per the procedure.
One step that I have found missing from the article is disconnecting the "Set Timing Connector" it must be disconnected before attempting to adjust the idle air set screw. This is so the ECM cannot control the timing while the idle is checked, or adjusted. Also the engine must be at normal operating temperature.

American Power

Where is the "set timing connector"? Could you send a picture? A picture would help tremendously.

rgarcia63

Picture is in my second reply to this thread https://www.thirdgen.org/forums/tpi/...iac-valve.html center of picture between wire looms

American Power

Hey thanks for the info. My tach reads 1500 when cold and 1250 when warm but the car is idling where it should and sounds fine. I believe the tach is old and inaccurate.