Chrysler Front Wheel Drive Cars 4-CYL 1981-1995 Repair Information

Idle Speed and Mixture Adjustments

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IDLE SPEED



Carbureted Engines

Always refer to Vehicle Emission Control Information (VECI) label in the engine compartment as a specification guide. The sticker information reflects running changes made by the manufacturer during production of the vehicle.

Carbureted vehicles use the Holley 5220/6250/6520 Series carburetors. Idle speed is adjusted on the top of the idle stop solenoid. Fuel injected cars, whether equipped with Throttle Body or Multi-Point injection use an Automatic Idle Speed motor. This is a throttle bypass system that is computer controlled, and DOES NOT require periodic adjustment (refer to Fuel System for additional information). To adjust the idle speed on carbureted vehicles, follow the appropriate procedure below.

2.2L ENGINE

See Figure 1

Click image to see an enlarged view

Fig. Fig. 1: Location of the idle speed set screw on the solenoid kicker-2.2L carbureted engines

  1. Make sure the ignition timing is sect correctly. Set the parking brake securely and put the transaxle in Neutral (manual) or Park (automatic). Turn off all lights and accessories. Connect a tachometer to the engine. Then, start it and allow it to run on the bottom step of the fast idle cam until it has reached operating temperature. Open the throttle so the engine will run at normal idle speed.
  2.  
  3. Unplug the radiator fan electrical connector and jumper the connector to ground to make the fan run continuously.
  4.  
  5. Pull the PCV valve out of the crankcase vent module.
  6.  
  7. Disconnect the oxygen feedback system test connector located on the left fender shield. Also disconnect the wiring from the kicker vacuum solenoid, also located on the left fender shield.
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  9. Turn the idle speed screw on top of the solenoid kicker to obtain the correct idle speed, as shown in the Tune-Up Specifications chart.
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  11. Reconnect the two disconnect connectors and install the PCV valve back into the vent module.
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  13. Increase rpm to about 2500 for 15 seconds and then return it to idle speed. Even though idle speed might be different now, you need not reset it. Disconnect the jumper wire and reconnect the fan motor connector. Turn off the engine.
  14.  

2.6L ENGINE

See Figure 2

Click image to see an enlarged view

Fig. Fig. 2: Location of the idle speed and idle mixture adjusting screws for the 2.6L engine

  1. Make sure the ignition timing is set correctly. Set the parking brake securely and put the transaxle in Neutral (manual) or Park (automatic). Turn off all lights and accessories. Connect a tachometer to the engine. Then, start it and allow it to run on the bottom step of the fast idle cam until it has reached operating temperature. Open the throttle so the engine will run at normal idle speed.
  2.  
  3. Unplug the radiator fan electrical connector. On 1983 and earlier models, allow the engine to idle for 1 minute to stabilize rpm.
  4.  
  5. On 1984 models, turn the engine off and then disconnect the negative battery cable for 3 seconds and reconnect it. Disconnect the engine harness lead from the O 2 sensor connector at the bullet connector. Avoid pulling on the sensor wire when doing this.
  6.  
  7. On 1983-85 models, open the throttle and allow the engine to run at 2500 rpm for 10 seconds. Then, return the engine to normal idle speed.
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  9. Wait two minutes.
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  11. Read the idle speed on the tach. If the rpm is not correct, and if the car has electronic feedback control, disconnect the idle switch connector. Now, if the rpm is not correct, turn the idle speed screw, accessible through the bracket on the carburetor body, to get the correct idle rpm.
  12.  
  13. If the car has air conditioning, set the temperature control level to the coldest position and turn the air conditioner on. Then, set the idle-up speed screw to obtain 900 rpm with the compressor running.
  14.  
  15. Turn off the engine, reconnect the fan, disconnect the tachometer, and reconnect the idle switch connector.
  16.  

Fuel-Injected Engines
CHRYSLER ELECTRONIC FUEL INJECTION (EFI) AND MULTI-POINT FUEL INJECTION (MFI) SYSTEMS

See Figure 3

Click image to see an enlarged view

Fig. Fig. 3: Idle speed adjusting screw location on MFI system throttle bodies

This procedure applies to vehicles built through 1986. The idle speed is controlled automatically by the PCM on 1987-95 models. 1987-95 models require a "Throttle Body Minimum Airflow Check Procedure'' to inspect the throttle body if any idling problems are evident. This cannot be performed without utilizing an expensive electronic test system. If airflow is incorrect on 1987-95 models, the entire throttle body must be replaced.

  1. Before adjusting the idle on an electronic fuel injected vehicle the following items must be checked.
    1. AIS motor has been checked for operation.
    2.  
    3. Engine has been checked for vacuum or EGR leaks.
    4.  
    5. Engine timing has been checked and set to specifications.
    6.  
    7. Coolant temperature sensor has been checked for operation.
    8.  

  2.  
  3. Connect a tachometer and timing light to engine.
  4.  
  5. Detach the throttle body 6-way connector. Remove the brown with white tracer AIS wire from the connector, then reattach the connector.
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  7. Connect one end of a jumper wire to the AIS wire and the other end to the battery positive post for 5 seconds.
  8.  
  9. Connect a jumper to radiator fan so that it will run continuously.
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  11. Start and run the engine for 3 minutes to allow idle speed to stabilize.
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  13. With the transaxle is Neutral and using tool C-4804 or equivalent, turn the idle speed adjusting screw to obtain 790-810 rpm for EFI models equipped with manual transaxles, to 715-735 rpm for automatic transaxle equipped EFI models, to 675-725 rpm for MFI green engines, and or to 750-800 rpm for other MFI engines.
  14.  

If the idle will not adjust down, check for binding linkage, speed control servo cable adjustments, or throttle shaft binding.

  1. Check that the ignition timing is at 16°-20° BTDC for vehicles equipped with manual transaxles, or at 10°-14° BTDC for automatic transaxles.
  2.  
  3. If timing is not within specifications, turn the idle speed adjusting screw until the correct idle speed and ignition timing are obtained.
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  5. Turn the engine OFF , disconnect the tachometer and timing light, reinstall AIS wire and remove jumper wire. Road test the vehicle for proper operation.
  6.  

EAGLE THROTTLE BODY FUEL INJECTION (TBI) SYSTEMS

On all fuel-injected models idle speed is automatically controlled by the Powertrain Control Module. The idle speed cannot manually be adjusted.

IDLE MIXTURE



Carbureted Engines

See Figure 4

Click image to see an enlarged view

Fig. Fig. 4: The location of the idle speed mixture adjusting screw for the 2.2L carbureted engines

Always refer to Vehicle Emission Control Information (VECI) label in the engine compartment as a specification guide. The sticker information reflects running changes made by the manufacturer during production of the vehicle.

Chrysler recommends the use of propane enrichment procedure to adjust the mixture. The equipment needed for this procedure is not readily available to the general public. The procedure is included here for reference purposes:

  1. Remove the concealment plug located under the choke housing.
  2.  
  3. Set the parking brake. As applicable, place either the manual transaxle in Neutral or the automatic transaxle in Park.
  4.  
  5. Connect a tachometer to the engine. Then, start it and allow it to run on the bottom step of the fast idle cam until it has reached operating temperature. Open the throttle so the engine will run at normal idle speed.
  6.  
  7. Unplug the radiator fan electrical connector and install a jumper wire so the fan runs continuously.
  8.  

  1. Pull the PCV valve out of the crankcase vent module so it will draw underhood air.
  2.  
  3. Disconnect the oxygen feedback system test connector located on the left fender shield.
  4.  
  5. Disconnect the vacuum harness from the CVSCC valve and plug both hoses. On the 2.2L engine only, disconnect the wiring from the single solenoid kicker vacuum control solenoid, which is located on the left fender shield.
  6.  
  7. Disconnect the vacuum hose which leads to the heated air sensor at the three-way connector and install the supply hose from the propane bottle where it was connected. Make sure the propane valves are fully closed and that the bottle is in a safe and secure position that will maintain it upright.
  8.  
  9. Open the propane main valve. Leaving the air cleaner in place, slowly and very steadily open the propane metering valve while you watch the tach, until maximum rpm is reached. You will note that there will be an optimum mixture, after which further addition of propane will cause the engine rpm to begin falling. Note what this rpm is and carefully adjust the propane valve to produce this exact rpm.
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  11. Adjust the idle speed screw on top of the solenoid kicker (without changing the propane setting) so that the tach reads the propane enrichment rpm shown on the engine compartment sticker.
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  13. Increase the engine speed to 2500 rpm for 15 seconds and then return it to idle. Read the rpm and, if it has changed, readjust the idle speed to give the specified rpm.
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  15. Turn off the propane system main valve and allow the engine speed to stabilize. With the air cleaner in place, slowly adjust the mixture screw to achieve the specified idle set rpm with an Allen wrench. Work very slowly and pause after slight adjustment increments to allow the engine rpm to stabilize. Again, increase the engine speed to 2500 rpm for 15 seconds and then return it to idle. Recheck the rpm.
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  17. Repeat the procedure of Step 7 to get optimum propane enrichment rpm at these new basic settings. Reread the tach. If this rpm is more than 25 rpm either side of the specified propane enrichment rpm, repeat the procedure starting with Step 7. The adjustment is correct when the test in this step is passed.
  18.  
  19. Turn off both propane valves, remove the propane supply hose, and reinstall the vacuum hose. Reinstall the concealment plug into the carburetor.
  20.  

Fuel-Injected Engines

The air/fuel mixture on all fuel-injected cars covered by this repair guide is automatically controlled by the Powertrain Control Module (PCM). The mixture is not adjustable, nor does it require routine adjusting.

 
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