86 TPI trans am idle problem
Thread Starter
Teching In
Joined: Dec 2012
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86 TPI trans am idle problem Hey I have a 1986 305 tuned port trans am and the idle is very low sometimes around 400 and it gets very close to dying.
At first i thought it was the TPS so i bought a new one and it is still the same. So i bought a multi meter and checked my voltage and i have a voltage on my ground wire at the TPS. So i went though and checked the voltage on the CTS and the MAT sensor. They both had the same voltage on the ground wire as the TPS. I was getting the error codes 22, 36, 33. and 12
I have done everything that i can and i am completely stumped. PLEASE help me fix this problem!!
Thanks, Grant.
At first i thought it was the TPS so i bought a new one and it is still the same. So i bought a multi meter and checked my voltage and i have a voltage on my ground wire at the TPS. So i went though and checked the voltage on the CTS and the MAT sensor. They both had the same voltage on the ground wire as the TPS. I was getting the error codes 22, 36, 33. and 12
I have done everything that i can and i am completely stumped. PLEASE help me fix this problem!!
Thanks, Grant.
Have you performed the IAC reset procedure? Do that first, then go from there. The TPI throttle stop is adjustable too, youll need to knock out the littler cover then use a torx to adjust the screw.
Tools needed:
1.Torx bit # T-20
2.Paper Clip
3.Small Punch
Take the paper clip and open it up and form it into a big "U" shape. Insert the clip ends into the ALDL in the 'A' and 'B' pins.
Turn on the ignition, but don't start the engine. Wait 30 seconds. Now, go remove the connector from the IAC.
Start engine. You are now going to adjust "minimum air". There is a Torx screw on the side of the throttle body. This is what needs to be turned to adjust minimum air, or more commonly known as "idle speed". It comes from the factory with a protective metal cap over it. If the cap is still there, use a small punch to knock it out. Set the idle speed to 450 rpm, rotating the Torx screw clockwise to raise rpm, and counter-clockwise to lower rpm. Once the idle rpm is set, turn off the engine.
Re-connect the connector onto the IAC. Start engine. Idle speed is now once again governed by the ECM, but your idle should be smooth and steady, approximately 600 rpm in Drive (for unmodified cars).
If you set an SES light by having the IAC disconnected, then after shutting down the engine disconnect the negative battery terminal. Wait 5 minutes. This will clear the ECM of all trouble codes. Re-connect the battery and drive the car for 20 minutes to allow the ECM to relearn your driving style.
1.Torx bit # T-20
2.Paper Clip
3.Small Punch
Take the paper clip and open it up and form it into a big "U" shape. Insert the clip ends into the ALDL in the 'A' and 'B' pins.
Turn on the ignition, but don't start the engine. Wait 30 seconds. Now, go remove the connector from the IAC.
Start engine. You are now going to adjust "minimum air". There is a Torx screw on the side of the throttle body. This is what needs to be turned to adjust minimum air, or more commonly known as "idle speed". It comes from the factory with a protective metal cap over it. If the cap is still there, use a small punch to knock it out. Set the idle speed to 450 rpm, rotating the Torx screw clockwise to raise rpm, and counter-clockwise to lower rpm. Once the idle rpm is set, turn off the engine.
Re-connect the connector onto the IAC. Start engine. Idle speed is now once again governed by the ECM, but your idle should be smooth and steady, approximately 600 rpm in Drive (for unmodified cars).
If you set an SES light by having the IAC disconnected, then after shutting down the engine disconnect the negative battery terminal. Wait 5 minutes. This will clear the ECM of all trouble codes. Re-connect the battery and drive the car for 20 minutes to allow the ECM to relearn your driving style.
Couldn't hurt to set the TPS as well:
Throttle Position Switch (TPS)
Tools needed:
1.Digital Volt-Ohm-Meter (VOM)
2.Jumper Wires (make your own)
3.Auto Xray Scanner (if available) will eliminate the need for VOM and jumper wires.
Turn on ignition, but don't start the engine.
With a scanner: plug in the scanner and read the TPS voltage. It should be 0.54Volts +/- 0.075Volts
With VOM and jumper wires: disconnect the connector from the TPS. Using your jumper wires, make a connection allowing some room for the VOM terminals to contact the jumper leads and read the TPS voltage.
If out of spec, loosen the two screws holding the TPS to the throttle body, and slightly rotate the TPS up or down, reading the voltage until it comes into specification. Tighten screws. Using the throttle lever, rotate the throttle to WOT (wide open throttle). The TPS voltage should be over 4.0 volts. Close the throttle again, and then slowly open it to WOT, observing the voltage reading. It should increase progressively and in a linear fashion. If it sticks or jumps or falls off at all while doing this check, that could mean a bad TPS switch and could be a cause of stumbling and driveability problems.
After setting the correct voltage, turn off ignition switch. Remove jumpers/scanner and reconnect the TPS connector as required.
Throttle Position Switch (TPS)
Tools needed:
1.Digital Volt-Ohm-Meter (VOM)
2.Jumper Wires (make your own)
3.Auto Xray Scanner (if available) will eliminate the need for VOM and jumper wires.
Turn on ignition, but don't start the engine.
With a scanner: plug in the scanner and read the TPS voltage. It should be 0.54Volts +/- 0.075Volts
With VOM and jumper wires: disconnect the connector from the TPS. Using your jumper wires, make a connection allowing some room for the VOM terminals to contact the jumper leads and read the TPS voltage.
If out of spec, loosen the two screws holding the TPS to the throttle body, and slightly rotate the TPS up or down, reading the voltage until it comes into specification. Tighten screws. Using the throttle lever, rotate the throttle to WOT (wide open throttle). The TPS voltage should be over 4.0 volts. Close the throttle again, and then slowly open it to WOT, observing the voltage reading. It should increase progressively and in a linear fashion. If it sticks or jumps or falls off at all while doing this check, that could mean a bad TPS switch and could be a cause of stumbling and driveability problems.
After setting the correct voltage, turn off ignition switch. Remove jumpers/scanner and reconnect the TPS connector as required.
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Thread Starter
Teching In
Joined: Dec 2012
Posts: 10
Likes: 0
okay thank you so much for this but i have two questions. where is the ALDL? is it under the the drivers dash in those pins or on the ECM under the passengers dash?
And do I need to have 3 jumper cables for the three connectors on the TPS?
And do I need to have 3 jumper cables for the three connectors on the TPS?
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