TPS Issue...i think

[chevelless502]

Ive been chasing a high idle problem for some time now. I recently got a copy of HP tuners to try to fix my issues plus for other tuning as well. Recently i took the intake off and found the MAF fitting on the back of the intake to be loose so i re siliconed it and also put in new vacuum lines because some re questionable. I restarted the car and it went to 2500 rpm then on up to just under 3000 rpm. So this is when i went ahead and hooked up the HP tuners to it and did a scan. The attached picture is what the scan read for the approx minute i left the car running. The TPS never did show anything. Can anyone tell me anything from that screen shot that could be my issue? Ive tried to go thru the relearn procedure on the TPS and it doesnt seem to do anything.
Thanks in advance for any help or advice.
Andy

[chevelless502]

Guessi should say this is on a 1998 Camaro that is relativly stock. Only a SLP lid and cat back exhaust. Its also hot a Hypertech tune in it as well.

[mowton]

So, you have a drive by cable throttle body setup in your 98 camaro and as such should see only 0% in Closed Throttle (CT) at idle. You have an Idle Air Control (IAC) on your throttle body which can open and close (via a stepper motor controlled by the PCM) and allow more or less air into the engine when at CT to maintain your idle rpm through a function called Adaptive Idle Control. To tune you idle you will have to first make sure that your MAF and VE are tuned pretty close to null.

The next steps require you log IAC Pos, IAC desired position, Dynamic airflow, Idle desired airflow, LTIT/IG, LTIT/PN, STIT, MAP, TPS% and TPS (V). First step is to adjust the Throttle Blade idle adjust set screw on the throttle body so the IAC POS is between 60 and 80 steps. The TPS (V) should be <.8volts and The TPS % should be 0%. If TPS % is not 0, then unplug TPS/IAC connector at the throttle Body, turn key on (don"t start) for 30 sec's, turn key off and plug TPS/IAC connector back in. Re verify the above settings and make any additional adjustments as required to get to 60-80 steps, 0% TPS and >.8V TPS (V).

Set up a histogram using Idle desired AF as the data and a table representing the BRAF table temperature points in your tune. Use the HP Tuners demo on PIDS and Hist generation for additional help in this. You can also search RussK idle configuration for additional help.

With the car cold, start logging and let idle without touch gas pedal until app 200F. It helps to shut off the Fans via the VCM controller in the Scanner and also make sure the AC/heater etc are off.When complete copy and paste the data collected by you histogram into the BRAF table of your tune. You may have to do this 2 or 3 times to get it perfect and if you have an automatic you will have to do both the In gear and P/N portions of the BRAF table.

As a precursor to this tuning process make sure all the idle, adaptive idle, over/underspeed spark adj, and Throttle Follower/Cracker tables are returned to stock values if they are not currently.

Ed M