Hyundai Coupes/Sedans 1986-1993 Repair Guide

Carburetor

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SERVICE ADJUSTMENTS



Throttle Linkage

See Figures 1 and 2



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Fig. Fig. 1: Accelerator cable adjusting nut on Excel



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Fig. Fig. 2: Accelerator linkage-Excel

  1. Run the engine to operating temperature and allow it to idle at curb idle speed.
  2.  
  3. There should be no slack in the exposed part of the throttle cable near the carburetor.
  4.  
  5. Make sure that there are no sharp bends in the cable.
  6.  
  7. Loosen the cable adjusting nut locknut and turn the adjusting nut until the throttle just starts to open.
  8.  
  9. At this point, back off the adjusting nut one full turn and lock it with the locknut.
  10.  

Fuel and Float Level Adjustment

See Figure 3

Float and fuel level adjustments are possible only on 1986-87 Excels



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Fig. Fig. 3: Adjusting shim location on needle seat-carbureted Excel

FUEL LEVEL

A sight glass is fitted in the float chamber and the fuel level can be checked without disassembling the carburetor. Normal fuel level is within the level mark on the sight glass. The fuel level adjustment is corrected by increasing or decreasing the number of needle valve packings (shims) between the valve and top cover.

FLOAT LEVEL

See Figure 4



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Fig. Fig. 4: Float adjustment-carbureted Excel

  1. Remove the carburetor air horn.
  2.  
  3. Turn it upside-down and measure the distance between the float bottom (which, inverted, is now the top), and the gasket surface of the air horn. The distance should be 20.0mm plus or minus 1.0mm.
  4.  
  5. Adjust the distance, as necessary, adding or deleting shims under the needle seat. Shim kits are available with shims in three thicknesses: 0.3mm, 0.4mm and 0.5mm. Each shim change will change the float setting by three times the thickness of the shim.
  6.  

Fast Idle Adjustment
1986-87 EXCEL

See Figure 5



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Fig. Fig. 5: Carburetor adjustment screws on Excel; SAS-1 is the curb idle screw; SAS-3 is the fast idle screw

  1. Start the engine and open the throttle valve about 45°deg;. Manually close the choke valve and slowly return the throttle valve to the stop position.
  2.  
  3. With a tachometer connected, check that the fast idle speed is 2000 rpm or lower. (Not less than 1700 rpm). Adjust the speed as necessary with the fast idle speed screw.
  4.  
  5. Cold start the engine and check the automatic choke and fast idle operation.
  6.  

1988-93 EXCEL

See Figures 6, 7 and 8

Before attempting the fast idle adjustment, make sure the following conditions are met:



Warm up car to normal operating temperature
 
Lights, cooling fan, electrical accessories set to OFF position
 
Transaxle in Neutral or Park
 
Steering wheel in straight ahead position (if equipped with power steering)
 



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Fig. Fig. 6: Disconnecting the choke opener vacuum hose for fast idle adjustment-carbureted Excel



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Fig. Fig. 7: Set the throttle lever to the second step on the fast idle cam for fast idle adjustment-carbureted Excel



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Fig. Fig. 8: Fast idle adjusting screw-carbureted Excel

  1. Remove the air cleaner and connect a tachometer to the engine.
  2.  
  3. Disconnect the vacuum hose (with the white stripe) from the choke opener.
  4.  
  5. Set the throttle lever to the second highest step on the fast idle cam.
  6.  
  7. Start the engine and check the fast idle speed. On manual transaxles, the fast idle speed should be 2800 rpm and on automatic transaxles it should be 2700 rpm.
  8.  
  9. If the fast idle speed is not within specification, adjust it with the fast idle adjusting screw.
  10.  
  11. Connect the choke opener vacuum hose, remove the tachometer and install the air cleaner.
  12.  

Idle Mixture Adjustment

See Figure 9

This adjustment is preset at the factory and is not a normal adjustment. Mixture adjustment is necessary only after unscheduled major maintenance has been performed on the carburetor. A CO meter is absolutely necessary for this procedure.



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Fig. Fig. 9: Drilling mixture adjustment access hole-carbureted Excel

  1. Remove the carburetor from the engine.
  2.  
  3. Secure the carburetor in a soft-jawed vise, without touching the gasket surface, and with the mixture adjusting screw (on the bottom) facing up.
  4.  
  5. Using a 2mm drill bit, drill a pilot hole in the casting surrounding the mixture adjusting screw at a 45°deg; angle. Then, redrill the hole with a 3mm ( 1 / 8 in.) bit.
  6.  
  7. Using a blunt punch in the hole, drive out the plug.
  8.  

Make sure all metal filings from drilling are completely removed before installing the carburetor on the engine.

  1. Install the carburetor on the engine.
  2.  
  3. Run the engine to normal operating temperature.
  4.  
  5. Make sure that the lights, electric cooling fan and all accessories are OFF. Place the transmission in neutral. Block the wheels and set the parking brake.
  6.  
  7. Run the engine for 5 seconds at 2000-3000 rpm.
  8.  
  9. Return the engine to idle and let it idle at normal curb idle speed for 2 minutes.
  10.  
  11. Make sure that the idle speed is correct. If not, adjust it with the idle speed screw.
  12.  
  13. Using a CO meter, adjust the idle CO by turning the mixture screw. CO level should meet state or local requirements.
  14.  

Secondary Throttle Plate Adjustment

The secondary throttle plate stop screw is adjusted to keep the throttle plate from closing too tightly. This adjustment is only made with the carburetor off of the engine. The screw is set at the factory and doesn't normally need adjustment.

Automatic Choke Adjustment

All carburetors are equipped with a tamper-proof choke that has been pre-adjusted at the factory. Choke adjustment should only be performed as part of major carburetor overhaul or choke calibration as required by state or local inspections.

1986-87 EXCEL

See Figures 10, 11, 12 and 13



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Fig. Fig. 10: Choke strangler spring-carbureted Excel

  1. Remove the air cleaner, and choke mechanism cover.
  2.  

These models have headless, tamper proof screws securing the choke mechanism cover. These have to be drilled out. In that case, it's easier to remove the carburetor.



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Fig. Fig. 11: Aligning the choke gear and cam-carbureted Excel

  1. Remove the bracket bridging the choke spring gear and choke actuating cam.
  2.  
  3. Slip the choke strangler spring from the choke lever. Align the scribed black line on the choke gear with the mark below the teeth on the actuating cam and reassemble all parts.
  4.  



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Fig. Fig. 12: Cam bracket attaching screws-carbureted Excel

  1. Temporarily tighten the lower bracket screw.
  2.  



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Fig. Fig. 13: Aligning the upper bracket arm and carburetor body marks-carbureted Excel

  1. Move the arm at the upper screw to align the center line scribed in the notch on the arm with the punch mark on the float chamber.
  2.  
  3. Tighten the screws.
  4.  
  5. Install the cover with new screws.
  6.  

1988-93 EXCEL

See Figures 14, 15 and 16

This check must be performed when the coolant temperature is at or lower than 50°deg;F (10°deg;C).



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Fig. Fig. 14: Choke and bi-metal assembly alignment-carbureted Excel



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Fig. Fig. 15: Choke breaker system-carbureted Excel



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Fig. Fig. 16: Use this table to inspect the condition of the choke valve-carbureted Excel

  1. Remove the air cleaner.
  2.  
  3. Check that the marks on the choke and bi-metal assembly are aligned properly. If not, rotate the bi-metal assembly until the marks are aligned. If the marks were in fact misaligned, you may have experienced the following symptoms:

    Clockwise misalignment: will result in good cold weather startability, but will cause carbon deposits on the plugs.
     
    Counterclockwise misalignment: will result in poor startability and stalling.
     

  4.  
  5. Make sure the coolant temperature is at or lower than 50°deg;F.
  6.  
  7. Start the engine and place your hand on the body of the choke. Check the operation of the choke, choke valve and fast idle cam as follows:
    1. Choke: As the engine warms up, the choke body should get hotter.
    2.  
    3. Choke valve: The choke valve will open at the bi-metal temperature rises.
    4.  
    5. Fast idle cam: The fast idle engine speed should stop after the engine warms up and the coolant temperature rises.
    6.  

  8.  
  9. If the choke body remains cool even after the engine is warm, then the electric choke breaker system must be checked out and adjusted as described in the procedure that immediately follows.
  10.  

Choke Breaker System Inspection And Adjustment

See Figures 17, 18 and 19



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Fig. Fig. 17: Measuring choke valve clearance-carbureted Excel



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Fig. Fig. 18: Adjusting the choke breaker rod opening-carbureted Excel



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Fig. Fig. 19: Using the choke breaker adjusting screw to adjust the choke valve clearance-carbureted Excel

1988-93 EXCEL

See Figures 20, 21 and 22

If the choke breaker system is suspect of malfunctioning, use the accompanying chart to check the operation of the choke valve and breaker system, then proceed to the adjustment section.

  1. Remove the air cleaner.
  2.  
  3. Disconnect the yellow striped vacuum hose from the choke breaker.
  4.  
  5. Start the engine and run at idle.
  6.  
  7. Lightly close the choke valve with your finger until it stops. DO NOT force it! With a feeler gauge, measure the clearance between the choke valve and the choke bore. The clearance should be 0.055-0.063 in.
  8.  
  9. If the choke valve clearance is not as specified, stop the engine and matchmark the bi-metal assembly to the choke body. Remove the bi-metal end cover from the choke valve lever. Then, adjust the choke breaker rod end opening until the 0.055-0.063 in. clearance is obtained. Install the bi-metal assembly, using new screws and rivets.
  10.  

These models have headless, tamper proof screws securing the choke mechanism cover. These have to be drilled out. In that case, it's easier to remove the carburetor.

  1. Reconnect the yellow striped vacuum hose to the choke breaker and re-check the choke valve to choke bore clearance again with the engine running. This time the clearance should be 0.114-0.122 in.
  2.  



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Fig. Fig. 20: Idle-up actuator-carbureted Excel



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Fig. Fig. 21: Adjusting the throttle opener for power steering and electrical loads-carbureted Excel

  1. If the clearance is not as specified, turn the choke breaker adjusting screw until the 0.114-0.122 in. clearance is obtained.
  2.  
  3. Stop the engine and install the air cleaner.
  4.  



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Fig. Fig. 22: A/C throttle opener adjustment-carbureted Excel



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Fig. Fig. 23: Idle-up control solenoid test-carbureted Excel

Throttle Opener (Idle-Up) Actuator Test

The throttle opener controls the idle speed when heavy electrical loads or power steering loads are placed upon the engine.

  1. Check that all vacuum hoses and wires at the actuator are connected.
  2.  
  3. Disconnect the vacuum hose at the actuator nipple.
  4.  
  5. Connect a tachometer to the engine.
  6.  
  7. Start the engine and allow it to reach normal operating temperature at curb idle speed. If the idle speed is not correct, adjust it.
  8.  
  9. Using a hand-held vacuum pump connected at the actuator nipple, apply 300mm Hg vacuum. The idle speed should increase. If not, replace the actuator.
  10.  

Throttle Opener (Idle-Up) Actuator Adjustment
  1. Remove the air cleaner assembly.
  2.  
  3. Connect a tachometer to the engine.
  4.  
  5. Start the engine and allow it to reach normal operating temperature at curb idle speed. If the idle speed is not correct, adjust it.
  6.  
  7. Apply an electrical load, such as the blower motor.
  8.  
  9. Disconnect the wiring from the idle-up solenoid valve and connect a jumper wire across the connector terminals on the valve. This will activate the valve and apply vacuum to and activate the idle-up actuator.
  10.  
  11. Now, open the throttle slightly until the engine speed reaches 2000 rpm. Then, let up on the throttle slowly.
  12.  
  13. Adjust the engine idle speed to 750-950 rpm by turning the throttle opener adjusting screw.
  14.  
  15. Repeat Step 5, and check the idle speed again. It should be 750-950 rpm.
  16.  
  17. Stop the engine and remove the idle-up solenoid jumper wire, remove the tachometer and install the air cleaner assembly.
  18.  

Throttle Opener (idle-Up) Adjustment

For Operation Under Air Conditioning Loads

1988-1993 EXCEL ONLY

This procedure is used to check and adjust the idle speed control function of the throttle opener when an air conditioning load is applied to the engine.

  1. Start the engine and connect a tachometer.
  2.  
  3. Turn the air conditioner on. The A/C solenoid will open and allow intake manifold vacuum to actuate the throttle opener.
  4.  
  5. Check the idle speed. If the idle speed is not within 850-900 rpm, adjust it by turning the A/C throttle adjusting screw.
  6.  

Throttle Opener (Idle-Up) Control Solenoid Valve Test
  1. With the ignition switch off, unplug the connector from the idle-up solenoid valve.
  2.  
  3. Using an ohmmeter, check continuity across the terminal. If an open or short is detected, replace the solenoid valve. Solenoid valve coil resistance should be about 40 ohms.
  4.  

Throttle Position Sensor Testing

See Figures 24, 25, 26 and 27



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Fig. Fig. 24: Throttle position sensor test connections-carbureted Excel



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Fig. Fig. 25: Idle speed adjusting screw 2 (SAS-2)

A digital ohmmeter is necessary for this adjustment.

  1. Disconnect the TPS connector.
  2.  



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Fig. Fig. 26: Adjusting the TPS output voltage-carbureted Excel



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Fig. Fig. 27: TPS adjustment points-carbureted Excel

  1. Check the resistance with an ohmmeter between terminals 2 and 3 (the bottom, adjacent terminals in the connector) on 1986-87 Excel and terminals 1 and 3 on 1988-89 Excel. With the throttle closed, resistance should be 1.2 ohms on 1986-87 Excel and 3.5k ohms on 1988-89 Excel. Resistance should slowly increase to 4.9 ohms on 1986-87 Excel and 6.5k ohms on 1988-89 Excel at wide open throttle.
  2.  

Throttle Position Sensor Adjustment

A digital voltmeter is necessary for this adjustment.

  1. Run the engine to normal operating temperature. Make sure that the fast idle cam is released.
  2.  
  3. Shut off the engine and loosen the throttle cable a small amount.
  4.  
  5. Back off SAS-1 and SAS-2, the two idle speed adjustment screws, until the throttle is fully closed. Record the exact number of turns that you backed each off.
  6.  
  7. Connect a digital voltmeter between terminals 2 and 3 (the two bottom ones) of the TPS connector.
  8.  

Do not disconnect the TPS connector from the chassis harness.

  1. Turn on the ignition switch and adjust the TPS output voltage to 250mV with the adjustment screw by turning the body of the TPS in either the clockwise or counterclockwise direction. Turning the TPS in the CLOCKWISE direction increases the output voltage.
  2.  
  3. Turn off the ignition switch.
  4.  
  5. Return the two idle speed adjustment screws to their exact positions.
  6.  
  7. Adjust the accelerator cable free-play, start the engine and check the idle speed.
  8.  

Jet Mixture Solenoid Test
1986-87 EXCEL

See Figure 28



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Fig. Fig. 28: Jet mixture solenoid test-carbureted Excel

  1. With the ignition switch ON but the engine not running, the voltage at the JMS checker should be 11-13v.
  2.  
  3. With the engine running at normal operating temperature at curb idle, the voltage at the checker should be 5-12v. If not, replace the JMS valve.
  4.  

REMOVAL & INSTALLATION



USA Vehicles
  1. Disconnect the negative battery cable. Drain the coolant down to below the level of the intake manifold.
  2.  
  3. Remove the air cleaner. Disconnect the throttle cable at the carburetor.
  4.  
  5. Disconnect and label all vacuum hoses.
  6.  
  7. Disconnect the connectors for the solenoid valves and the Throttle Position Sensor (TPS).
  8.  
  9. Place a pan under the fuel connections and then disconnect them. Remove the container, avoiding the spilling of fuel.
  10.  
  11. Remove the mounting bolts, lift the carburetor off the engine and remove it to a workbench, keeping it level to avoid the spilling of fuel from the float bowl.
  12.  

To install:
  1. Inspect the mating surfaces of the carburetor and manifold. They should be clean and free of nicks or burrs. Clean and, if necessary, remove any slight imperfections with crocus cloth. Put a new carburetor gasket on the surface of the manifold.
  2.  
  3. Position the carburetor on top of the gasket with all holes aligned. Install the carburetor bolts and tighten them alternately and evenly.
  4.  
  5. Connect the throttle linkage. Depress the accelerator pedal and make sure the throttle blade opens all the way. Adjust, if necessary.
  6.  
  7. Connect the vacuum hoses. Make sure all are soft and free of cracks to make a good seal. Replace hoses that are hard and cracked. Reconnect the fuel hoses.
  8.  
  9. Install the remaining parts in reverse order. Connect the negative battery cable. To start the engine, set the choke and operate the starter. Do not attempt to prime the engine by pouring gas into the carburetor inlet. Check for leaks with the engine running.
  10.  

Canadian Vehicles
  1. Disconnect the negative battery cable.
  2.  
  3. Drain the coolant to a level just below the intake manifold.
  4.  
  5. Remove the air cleaner.
  6.  
  7. Disconnect the wiring from the fuel cutoff solenoid.
  8.  
  9. Disconnect the accelerator rod and, if equipped with automatic transaxle, the shift rod.
  10.  
  11. Tag and disconnect the vacuum hoses from the carburetor.
  12.  
  13. Place a container under the fuel inlet and return hoses to catch any leaking fuel and disconnect the hoses.
  14.  
  15. Disconnect the water hose which runs between the carburetor and the cylinder head.
  16.  
  17. Unscrew the 4 retaining nuts and remove the carburetor. Hold the carburetor level to avoid a fuel spill.
  18.  

To install:
  1. Mount the carburetor on the intake manifold and install nuts. Attach the choke water hose to the carburetor.
  2.  
  3. Reconnect the fuel lines and vacuum hoses to the carburetor.
  4.  
  5. Connect the accelerator or shift rod.
  6.  
  7. Reconnect the fuel cut-off solenoid and replace the air cleaner.
  8.  
  9. Refill the system with coolant. Connect the negative battery cable.
  10.  

 
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