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

Carburetor Adjustments

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ADJUSTMENTS



Idle Speed
HOLLEY 5220/6520

See Figure 1

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Fig. Fig. 1: To adjust the idle speed, turn the screw on the top of the idle stop solenoid

The Holley 5220/6520 carburetors are used only on the 2.2L engine. This procedure is performed while the carburetor is installed on the engine.

  1. Install a tachometer on the engine following the manufacturer's instructions.
  2.  
  3. Put the transaxle in Neutral and set the parking brake securely.
  4.  
  5. Turn all accessories OFF.
  6.  
  7. Allow the engine to warm up on the lowest step of the fast idle cam.
  8.  
  9. Make the following preparations for adjustment, depending on the year:
    1. Disconnect and plug the vacuum connector at the CVSCC (Coolant Vacuum Switch Cold Closed) on 1981-84 engines, so equipped.
    2.  
    3. Pull the PCV valve out of the vent module and allow it to breathe underhood air.
    4.  
    5. Disconnect the oxygen feedback system test connector located on the left fender shield, if working on a 6520 carburetor.
    6.  
    7. Disconnect the wiring from the kicker solenoid located on the left fender shield on 1986 models. On 1981-85 models so-equipped, ground the carburetor switch with a jumper wire.
    8.  

  10.  
  11. If the tachometer indicates the rpm is not set to specifications, turn the idle speed screw, located on the top of the idle solenoid, until the correct rpm is achieved. Refer to the underhood sticker on the vehicle or to the Gasoline Engine Tune-up chart in Routine Maintenance for correct idle speed.
  12.  
  13. Restore the PCV system and other vacuum and electrical connections. Road test the vehicle for proper operation.
  14.  

MIKUNI

See Figures 2 and 3

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Fig. Fig. 2: Adjust the idle speed screw with a long, slender screwdriver as shown



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Fig. Fig. 3: Location of the idle-up (air conditioner ON) adjustment screw

The Mikuni carburetor is used only on the 2.6L engine. This procedure is performed while the carburetor is installed on the engine.

  1. Place the transaxle in Neutral, set the parking brake, and turn OFF all accessories.
  2.  
  3. Disconnect the radiator fan.
  4.  
  5. Run the engine until it reaches operating temperature. On 1981-83 models, allow the engine to idle for one minute to stabilize the rpm.
  6.  
  7. On 1984 models, turn the engine OFF . Disconnect the negative battery cable for three seconds, then reconnect it.
  8.  
  9. Detach the engine wiring harness lead from the O 2 sensor at the bullet connector. Don't pull on the sensor wire in doing this; only pull on the connector boot.
  10.  
  11. Attach a tachometer to the engine according to the tool manufacturer's instructions.
  12.  
  13. Restart the engine.
  14.  
  15. On 1984-85 vehicles, run the engine at 2,500 rpm for 10 seconds. Then, wait two minutes before checking idle speed.
  16.  
  17. Check the idle speed with the tachometer. If the idle rpm is not within specifications:
    1. On 1983-84 models-disconnect idle switch connector, if the idle speed must be adjusted. Adjust the idle speed with the idle screw.
    2.  
    3. On A/C models-turn on the air conditioning with the temperature control lever set to the coldest setting. If the rpm is not approximately 900, turn the idle-up screw to obtain this reading.
    4.  

  18.  
  19. Turn the engine OFF and reattach all connectors. Road test the vehicle for proper operation.
  20.  

Air Conditioning Idle Speed
HOLLEY 5220/6520

See Figure 4

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Fig. Fig. 4: To adjust the idle speed for when the A/C is engaged, turn to the recessed screw with an Allen wrench

This adjustment is required on 1981-82 2.2L engines only. On later models, just verify that the A/C idle speed kicker works. This procedure is performed while the carburetor is installed on the engine.

  1. Turn the air conditioner ON and set the blower on low. Disconnect and plug the EGR valve vacuum hose.
  2.  
  3. Remove the adjusting screw and spring from the top of the air conditioning solenoid.
  4.  
  5. Insert a 1 / 8 in. Allen wrench into the solenoid and adjust to obtain the correct idle speed, as indicated on the underhood sticker.
  6.  
  7. Make sure that the air conditioning clutch is operating during the speed adjustments.
  8.  
  9. Reinstall the adjusting screw and spring onto the solenoid and turn the air conditioner OFF.
  10.  

Fast Idle Speed
HOLLEY 5220/6520

See Figure 5

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Fig. Fig. 5: Turn the adjusting screw with a screwdriver to raise or lower the fast idle speed-make sure that the adjusting screw is resting against the lowest speed step

This procedure is performed while the carburetor is installed on the engine.

  1. On 1981-82 cars, disengage the two-way electrical connector at the carburetor (red and tan wires).
  2.  
  3. On all years, disconnect the jumper wire at the radiator fan and install a jumper wire so that the fan runs continuously.
  4.  
  5. On 1983-86 models, pull the PCV valve out of the valve cover and allow it to draw underhood air.
  6.  
  7. Disengage the oxygen sensor system connector located on the left fender shield near the shock tower.
  8.  
  9. Ground the carburetor switch with a jumper wire.
  10.  
  11. Open the throttle slightly and place the adjustment screw on the slowest speed step of the fast idle cam.
  12.  
  13. With the choke fully open, adjust the fast idle speed to comply with the value indicated on the underhood sticker.
  14.  
  15. Return the vehicle to curb idle, then reposition the adjusting screw on the slowest speed step of the fast idle cam to verify fast idle speed. Re-adjust as necessary.
  16.  
  17. Turn the engine OFF , remove the jumper wire and reconnect the fan.
  18.  
  19. Reinstall the PCV valve and remove the tachometer. On 1983-86 models, reattach the oxygen sensor system connector, and remove the jumper wire from the carburetor.
  20.  

Fast Idle Opening
MIKUNI
  1. Before adjustment, leave the carburetor alone for approximately one hour at 73°F (23°C).
  2.  
  3. Adjust the fast idle opening by turning the fast idle adjusting screw to the following specified values (drill diameter):

    2.6L engines equipped with manual transaxles-0.028 in.
     
    2.6L engines equipped with automatic transaxles-0.031 in.
     

  4.  

Choke Valve Setting
MIKUNI

See Figure 6

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Fig. Fig. 6: After tightening the choke cover lockscrews, cut the heads off of lockscrews A (total of 3 screws) and stake the heads of lockscrews B (total of 2 screws) with a blunt punch

This procedure need only be performed if the carburetor is disassembled.

  1. Fit the strangler spring to the choke lever.
  2.  
  3. Assemble the choke valve, aligning the inscribed line or black painted line on the tooth of the choke pinion with the inscribed line on the cam lever.
  4.  
  5. Temporarily tighten the new lockscrews.
  6.  
  7. Set the choke valve by moving the pinion arm up or down, align a punched mark on the float chamber cover at the center of the three inscribed lines, and secure the pinion arm with the lockscrews.
  8.  
  9. Install the choke cover and tighten the lockscrews.
  10.  
  11. Cut off the heads off of lockscrews A .
  12.  
  13. Stake the heads of lockscrews B using a blunt punch.
  14.  

Vacuum Kick
HOLLEY 5220/6520

This procedure is performed while the carburetor is installed on the engine.

If the vacuum kick is adjusted to open the choke too far, the engine may stall or idle very roughly just after cold start. If it is adjusted so that the choke does not open enough, there may be black smoke in the exhaust.

To perform this procedure, you will need a hand held vacuum pump capable of producing at least 15 in. Hg (50.6 kPa) of vacuum. The vacuum kick diaphragm may be damaged if you attempt to retract it manually. You will also need a drill or dowel which has a diameter equivalent to the specification for Vacuum Kick in the Carburetor Specifications Chart.

  1. Remove the air cleaner. Open the throttle, close the choke and hold it in the closed position, and then release the throttle to trap the fast idle cam in the choke-closed position.
  2.  
  3. Disconnect the vacuum hose at the choke vacuum kick diaphragm. Connect a vacuum pump and apply 15 in. Hg (50.6 kPa) or more of vacuum.
  4.  
  5. Gently move the choke blade toward the closed position just until play is eliminated from the vacuum kick linkage (so that the vacuum kick is determining choke blade position).
  6.  
  7. Insert the drill or dowel into the gap between the upper edge of the choke blade and the air horn wall, toward the center of the gap. The dowel or drill should just fit into the gap. If necessary, rotate the Allen head screw in the center of the diaphragm housing to create the proper gap and then recheck with the measuring device.
  8.  
  9. Restore all vacuum connections and reinstall the air cleaner.
  10.  

Air/Fuel Mixture Adjustment

See Figure 7

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Fig. Fig. 7: 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.

Mixture screws are sealed under tamperproof plugs. The only time mixture adjustments are necessary is during a major carburetor overhaul. Refer to the instructions supplied with the overhaul kit.

  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.  
  9. Pull the PCV valve out of the crankcase vent module so it will draw underhood air.
  10.  
  11. Disconnect the oxygen feedback system test connector located on the left fender shield.
  12.  
  13. 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.
  14.  
  15. 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.
  16.  
  17. 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.
  18.  
  19. 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.
  20.  
  21. 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.
  22.  
  23. 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.
  24.  
  25. 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.
  26.  
  27. Turn off both propane valves, remove the propane supply hose, and reinstall the vacuum hose. Reinstall the concealment plug into the carburetor.
  28.  

Float Level Adjustment
HOLLEY 5220/6520

See Figures 8 and 9

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Fig. Fig. 8: Adjust the float level on Holley 5220/6520 carburetors with a properly-sized gauge or drill bit as shown



Click image to see an enlarged view

Fig. Fig. 9: Use two rulers or straightedges affixed at a right angle to correctly measure the amount of float drop

The carburetor must be removed from the engine to perform this procedure.

  1. Remove the air horn from the carburetor body.
  2.  
  3. Invert the air horn and remove the gasket.
  4.  
  5. Insert a gauge or drill bit 12mm in diameter between the air horn and float. The gauge must lay flat along the gasket surface.
  6.  
  7. If the float's position is not correct, bend the tang, which actuates the needle valve, to correct it. Bend the tang up toward the floats to decrease the measurement and downward to increase it.
  8.  
  9. Check float drop with a float drop gauge or using a ruler and straightedge. Float drop must be 1.87 in. (47.5mm).
  10.  
  11. Bend the tang on the outer end of the float hinge outward to increase float drop and inward to decrease it.
  12.  
  13. Install the air horn onto the carburetor body.
  14.  

MIKUNI

See Figures 10 and 11

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Fig. Fig. 10: Measure the float level with two rulers or straightedges as shown



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Fig. Fig. 11: The shims, which adjust the height of the float, are located under the needle seat

The Mikuni carburetor is used only on the 2.6L engine. The carburetor must be removed from the engine to perform this procedure. Also, before attempting to adjust float level, acquire shim pack (part No. MD606952) or equivalent. These shims are placed under the float needle seat to change its position and, therefore, the float level.

  1. Remove the air horn from the carburetor.
  2.  
  3. Invert the air horn and remove the gasket.
  4.  
  5. Measure the distance from the bottom of the float to the surface of the air horn. The dimension must be 0.75-0.83 in. (19-21mm).
  6.  
  7. If the dimension is incorrect, disassemble the float, remove the needle and unscrew the float needle seat. Change the shim under the seat or add or subtract shims as necessary. Shims are 0.30mm, 0.40mm and 0.50mm thick. Adding a shim of 0.30mm will lower the float level by three times that amount (0.90mm).
  8.  
  9. Reassemble the seat, needle and float and recheck the level. Repeat the process until the float level is within the required range.
  10.  
  11. Install the air horn onto the carburetor body.
  12.  

 
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