How to fix rough, wandering, or high idle problems
Nov 10, 2008 1:43:20 GMT -5
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Post by Stinger on Nov 10, 2008 1:43:20 GMT -5
Q: My car's idle is rough, wandering, too high, too low, gets stuck at a high rpm when I push in the clutch, etc.
A: Follow the procedures below to fix any idle issues:
Base Idle Reset
1. Bring car up to operating temperature.
2. Unplug the IAC.
3. With the IAC disconnected and the idle adjusted to 750 RPM, shut off the engine and plug the IAC back in.
4. Unplug the battery cable and let it sit for 30 minutes.
5. Hook the battery back up and start the engine.
6. Let the car idle for 10 minutes and then go for a drive. It may take up to 75 miles for the computer to fully reset and learn the new settings.
Throttle Position Sensor (TPS) Adjustment
Symptoms: high idle, won't idle, dies when throttle is lifted when slowing down, surging idle speed
1. First bring the engine up to normal operating temperature.
2. Turn the engine off and unplug the Idle Air Control (IAC). This is located on the backside of the Throttle Body near the firewall. This device is a round cylinder approximately 5 inches long with a 2 bolt flange and 3 wire male / female plug connector.
3. Start engine and using a screwdriver adjust the base idle to 700 � 800 RPM using the screw on the throttle body.
4. Locate the Throttle Position Sensor (TPS) on the Throttle Body. This is also located on the backside of the Throttle Body near the firewall. This is a black plastic device with (2) screws that allows adjustment and (3) wire male / female connector (see pic above). Connect the voltmeter to the TPS and ground. The wire should be either black with a green stripe or green with a black stripe.
5. Using the small Phillips screwdriver adjust the TPS output voltage to approximately 1.0 volts. Most turbo tuners find that setting your voltage to around .90 - .95 volts works best. I set mine around .94 volts.
6. Turn off the engine.
7. With the engine off and the voltmeter still connected move the throttle linkage slowly from idle position to wide open and back to idle, look for a steady increase and then decrease in voltage without any voids or dead spots. Any voids or dead spots would indicate a faulty TPS. If you find a dead spot you need to replace the TPS.
8. Plug in the IAC.
9. Start the engine. The engine�s idle speed should settle in around 1000 RPM. If it settles higher than this, adjust the screw until idle is at 1000 RPM.
10. Go for a test drive and enjoy the smooth idle.
Idle Air Sensor (IAC) Cleaning & Adjustment
Symptoms: wandering idle, high idle, idle problems when at operating temperature.
1. Bring engine up to operating temperature. This is located on the backside of the Throttle Body near the firewall. This device is a round cylinder approximately 5 inches long with a (2) bolt flange and 3 wire male / female plug connector (see pic above).
2. Turn the engine off and unplug the Idle Air Control.
3. Remove 2 screws near the plug.
4. Remove two bolts holding the cylinder on the throttle body.
5. Push "piston" inside canister in and out to see if it moves freely.
6. Spray carb cleaner into piston area and move piston to clear out carbon deposits, repeat.
7. Blow out the excess cleaner and carbon deposits with compressed air (your mouth will suffice if it must)
8. Install cylinder with bolts.
9. Install plug with screws.
10. Start car, if it won't stay running then turn the idle adjustment screw on the throttle body towards the driver's side until it will stay running.
11. Turn the idle screw until it reaches 600-700rpm at idle.
12. Plug in 3 wire connector, if the IAC is functioning the engine should smooth out and the idle should jump up to 1000-1500 RPM.
13. Turn the idle screw until it idles at 1000rpm. Rev engine a few times to be sure it stays at 1000rpm at idle.
14. Remove tools, shut hood, and go for a drive.
A: Follow the procedures below to fix any idle issues:
Base Idle Reset
1. Bring car up to operating temperature.
2. Unplug the IAC.
3. With the IAC disconnected and the idle adjusted to 750 RPM, shut off the engine and plug the IAC back in.
4. Unplug the battery cable and let it sit for 30 minutes.
5. Hook the battery back up and start the engine.
6. Let the car idle for 10 minutes and then go for a drive. It may take up to 75 miles for the computer to fully reset and learn the new settings.
Throttle Position Sensor (TPS) Adjustment
Symptoms: high idle, won't idle, dies when throttle is lifted when slowing down, surging idle speed
1. First bring the engine up to normal operating temperature.
2. Turn the engine off and unplug the Idle Air Control (IAC). This is located on the backside of the Throttle Body near the firewall. This device is a round cylinder approximately 5 inches long with a 2 bolt flange and 3 wire male / female plug connector.
3. Start engine and using a screwdriver adjust the base idle to 700 � 800 RPM using the screw on the throttle body.
4. Locate the Throttle Position Sensor (TPS) on the Throttle Body. This is also located on the backside of the Throttle Body near the firewall. This is a black plastic device with (2) screws that allows adjustment and (3) wire male / female connector (see pic above). Connect the voltmeter to the TPS and ground. The wire should be either black with a green stripe or green with a black stripe.
5. Using the small Phillips screwdriver adjust the TPS output voltage to approximately 1.0 volts. Most turbo tuners find that setting your voltage to around .90 - .95 volts works best. I set mine around .94 volts.
6. Turn off the engine.
7. With the engine off and the voltmeter still connected move the throttle linkage slowly from idle position to wide open and back to idle, look for a steady increase and then decrease in voltage without any voids or dead spots. Any voids or dead spots would indicate a faulty TPS. If you find a dead spot you need to replace the TPS.
8. Plug in the IAC.
9. Start the engine. The engine�s idle speed should settle in around 1000 RPM. If it settles higher than this, adjust the screw until idle is at 1000 RPM.
10. Go for a test drive and enjoy the smooth idle.
Idle Air Sensor (IAC) Cleaning & Adjustment
Symptoms: wandering idle, high idle, idle problems when at operating temperature.
1. Bring engine up to operating temperature. This is located on the backside of the Throttle Body near the firewall. This device is a round cylinder approximately 5 inches long with a (2) bolt flange and 3 wire male / female plug connector (see pic above).
2. Turn the engine off and unplug the Idle Air Control.
3. Remove 2 screws near the plug.
4. Remove two bolts holding the cylinder on the throttle body.
5. Push "piston" inside canister in and out to see if it moves freely.
6. Spray carb cleaner into piston area and move piston to clear out carbon deposits, repeat.
7. Blow out the excess cleaner and carbon deposits with compressed air (your mouth will suffice if it must)
8. Install cylinder with bolts.
9. Install plug with screws.
10. Start car, if it won't stay running then turn the idle adjustment screw on the throttle body towards the driver's side until it will stay running.
11. Turn the idle screw until it reaches 600-700rpm at idle.
12. Plug in 3 wire connector, if the IAC is functioning the engine should smooth out and the idle should jump up to 1000-1500 RPM.
13. Turn the idle screw until it idles at 1000rpm. Rev engine a few times to be sure it stays at 1000rpm at idle.
14. Remove tools, shut hood, and go for a drive.