GM Cavalier/Sunbird/Skyhawk/Firenza 1982-1994

Carburetor

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The Rochester E2SE is used on all models. It is a two barrel, two stage carburetor of downdraft design used in conjunction with the Computer Command Control system of fuel control. The carburetor has special design features for optimum air/fuel mixture control during all ranges of engine operation.

MODEL IDENTIFICATION



See Figure 1

General Motors Rochester carburetors are identified by their model code. The first number indicates the number of barrels, while one of the last letters indicates the type of choke used. These are V for the manifold mounted choke coil, C for the choke coil mounted in the carburetor body, and E for electric choke, also mounted on the carburetor. Model codes ending in A indicate an altitude-compensation carburetor.



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Fig. Fig. 1: The carburetor identification number is stamped on the fuel bowl

PRELIMINARY CHECKS



The following should be observed before attempting any adjustments.

  1. Thoroughly warm the engine. If the engine is cold, be sure that it reaches operating temperature.
  2.  
  3. Check the torque of all carburetor mounting nuts and assembly screws. Also check the intake manifold-to-cylinder head bolts. If air is leaking at any of these points, any attempts at adjustment will inevitably lead to frustration.
  4.  
  5. Check the manifold heat control valve (if used) to be sure that it is free.
  6.  
  7. Check and adjust the choke as necessary.
  8.  
  9. Adjust the idle speed and mixture. If the mixture screws are capped, don't adjust them unless all other causes of rough idle have been eliminated. If any adjustments are performed that might possibly change the idle speed or mixture, adjust the idle and mixture again when you are finished.
  10.  

Before you make any carburetor adjustments make sure that the engine is in tune. Many problems which are thought to be carburetor-related can be traced to an engine which is simply out-of-tune. Any trouble in these areas will have symptoms like those of carburetor problems.

ADJUSTMENTS



Float Adjustment

See Figure 2

  1. Remove the air horn from the throttle body.
  2.  
  3. Use your fingers to hold the retainer in place, and to push the float down into light contact with the needle.
  4.  
  5. Measure the distance from the toe of the float (furthest from the hinge) to the top of the carburetor (gasket removed).
  6.  
  7. To adjust, remove the float and gently bend the arm to specification. After adjustment, check the float alignment in the chamber.
  8.  



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Fig. Fig. 2: Adjusting the float on the E2SE carburetor

Accelerator Pump Adjustment

E2SE carburetors have a non-adjustable pump lever. Adjustment is neither necessary or possible.

Fast Idle Adjustment

See Figure 3

  1. Set the ignition timing and curb idle speed, and disconnect and plug hoses as directed on the emission control decal.
  2.  



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Fig. Fig. 3: Fast idle adjustment

  1. Place the fast idle screw on the highest step of the cam.
  2.  
  3. Start the engine and adjust the engine speed to specification with the fast idle screw.
  4.  

Choke Coil Lever Adjustment

See Figure 4

  1. Remove the three retaining screws and remove the choke cover and coil. On models with a riveted choke cover, drill out the three rivets and remove the cover and choke coil.
  2.  



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Fig. Fig. 4: Adjusting the choke coil lever

A choke stat cover retainer kit is required for reassembly.

  1. Place the fast idle screw on the high step of the cam.
  2.  
  3. Close the choke by pushing in on the intermediate choke lever.
  4.  
  5. Insert a drill or gauge of the specified size into the hole in the choke housing. The choke lever in the housing should be up against the side of the gauge.
  6.  
  7. If the lever does not just touch the gauge, bend the intermediate choke rod to adjust.
  8.  

Fast Idle Cam (Choke Rod) Adjustment

See Figure 5

A special angle gauge must be used.

  1. Adjust the choke coil lever and fast idle first.
  2.  
  3. Rotate the degree scale until it is zeroed.
  4.  



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Fig. Fig. 5: Fast idle cam (choke rod) adjustment

  1. Close the choke and install the degree scale onto the choke plate. Center the leveling bubble.
  2.  
  3. Rotate the scale so that the specified degree is opposite the scale pointer.
  4.  
  5. Place the fast idle screw on the second step of the cam (against the high step). Close the choke by pushing in the intermediate lever.
  6.  
  7. Bend the fast idle cam rod at the U to adjust the angle to specifications.
  8.  

Air Valve Rod Adjustment

See Figure 6

  1. Seat the vacuum diaphragm with an outside vacuum source. Tape over the purge bleed hole if present.
  2.  
  3. Close the air valve.
  4.  
  5. Insert the specified gauge between the rod and the end of the slot in the plunger.
  6.  



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Fig. Fig. 6: Adjusting the air rod valve

  1. Bend the rod to adjust the clearance.
  2.  

Primary Side Vacuum Break Adjustment

See Figure 7

  1. Follow Steps 1-4 of the Fast Idle Cam Adjustment.
  2.  



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Fig. Fig. 7: Adjusting the primary side vacuum break

  1. Seat the choke vacuum diaphragm with an outside vacuum source.
  2.  
  3. Push in on the intermediate choke lever to close the choke valve, and hold closed during adjustment.
  4.  
  5. Adjust by using a 1 / 8 in. (3mm) hex wrench to turn the screw in the rear cover until the bubble is centered.
  6.  
  7. After adjusting, apply RTV silicone sealant over the screw to seal the setting.
  8.  

Secondary Vacuum Break Adjustment

See Figure 8

  1. Follow Steps 1-4 of the Fast Idle Cam Adjustment.
  2.  
  3. Seat the choke vacuum diaphragm with an outside vacuum source.
  4.  



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Fig. Fig. 8: Secondary side vacuum break adjustment

  1. Push in on the intermediate choke lever to close the choke valve, and hold closed during adjustment. Make sure the plunger spring is compressed and seated, if present.
  2.  
  3. Adjust by using a 1 / 8 in. (3mm) hex wrench to turn the screw in the rear cover until the bubble is centered.
  4.  
  5. After adjusting, apply RTV silicone sealant over the screw to seal the setting.
  6.  

Choke Unloader Adjustment

See Figure 9

  1. Follow Steps 1-4 of the Fast Idle Cam Adjustment.
  2.  
  3. Hold the primary throttle wide open.
  4.  



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Fig. Fig. 9: Choke unloader adjustment

  1. If the engine is warm, close the choke valve by pushing in on the intermediate choke lever.
  2.  
  3. Bend the unloader tang until the bubble is centered.
  4.  

Secondary Lockout Adjustment

See Figure 10

  1. Pull the choke wide open by pushing out on the intermediate choke lever.
  2.  



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Fig. Fig. 10: Secondary lockout adjustment

  1. Open the throttle until the end of the secondary actuating lever is opposite the toe of the lockout lever.
  2.  
  3. Gauge clearance between the lockout lever and secondary lever should be as specified.
  4.  
  5. To adjust, bend the lockout lever where it contacts the fast idle cam.
  6.  

REMOVAL & INSTALLATION



See Figures 11 and 12



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Fig. Fig. 11: View of the Rochester E2SE carburetor components

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the air cleaner and gasket.
  4.  
  5. Disconnect the fuel pipe and all vacuum lines.
  6.  



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Fig. Fig. 12: Exploded view of the carburetor mounting

  1. Tag and detach all electrical connections.
  2.  
  3. Disconnect the downshift cable.
  4.  
  5. If equipped with cruise control, disconnect the linkage.
  6.  
  7. Unscrew the carburetor mounting bolts, then remove the carburetor.
  8.  

To install:
  1. Before installing the carburetor, fill the float bowl with gasoline to reduce the battery strain and the possibility of backfiring when the engine is started again.
  2.  
  3. Inspect the EFE heater for damage. Be sure that the throttle body and EFE mating surfaces are clean.
  4.  
  5. Install the carburetor and tighten the nuts alternately to the proper specifications. Refer to the accompanying figure.
  6.  
  7. Installation of the remaining components is the reverse of the removal procedure.
  8.  

OVERHAUL



General Information

Efficient carburetion depends greatly on careful cleaning and inspection during overhaul, since dirt, gum, water, or varnish in or on the carburetor parts are often responsible for poor performance.

Overhaul your carburetor in a clean, dust-free area. Carefully disassemble the carburetor, referring often to the exploded views and directions packaged with the rebuilding kit. Keep all similar and look-alike parts segregated during disassembly and cleaning to avoid accidental interchange during assembly. Make a note of all jet sizes.

When the carburetor is disassembled, wash all parts (except diaphragms, electric choke units, pump plunger, and any other plastic, fiber, or rubber parts) in clean carburetor solvent. Do not leave parts in the solvent any longer than is necessary to sufficiently loosen the deposits. Excessive cleaning may remove the special finish from the float bowl and choke valve bodies, leaving these parts unfit for service. Rinse all parts in clean solvent and blow them dry with compressed air or allow them to air dry. Wipe clean all cork, plastic, and fiber parts with a clean, lint-free cloth.

Blow out all passages and jets with compressed air and be sure that there are no restrictions or blockages. Never use wire or similar tools to clean jets, fuel passages, or air bleeds. Clean all jets and valves separately to avoid accidental interchange.

Check all parts for wear or damage. If wear or damage is found, replace the defective parts. Especially check the following:

  1. Check the float needle and seat for wear. If wear is found, replace the complete assembly.
  2.  
  3. Check the float hinge pin for wear and the float(s) for dents or distortion. Replace the float if fuel has leaked into it.
  4.  
  5. Check the throttle and choke shaft bores for wear or an out-of-round condition. Damage or wear to the throttle arm, shaft, or shaft bore will often require replacement of the throttle body. These parts require a close tolerance of fit; wear may allow air leakage, which could affect starting and idling.
  6.  

Throttle shafts and bushings are not included in overhaul kits. They may be purchased separately.

  1. Inspect the idle mixture adjusting needles for burrs or grooves. Any such condition requires replacement of the needle, since you will not be able to obtain a satisfactory idle.
  2.  
  3. Test the accelerator pump check valves. They should pass air one way but not the other. Test for proper seating by blowing and sucking on the valve. Replace the valve check ball and spring as necessary. If the valve is satisfactory, wash the valve parts again to remove breath moisture.
  4.  
  5. Check the bowl cover for warped surfaces with a straightedge.
  6.  
  7. Closely inspect the accelerator pump plunger for wear and damage, replacing as necessary.
  8.  
  9. After the carburetor is assembled, check the choke valve for freedom of operation.
  10.  

Carburetor overhaul kits are recommended for each overhaul. These kits contain all gaskets and new parts to replace those which deteriorate most rapidly. Failure to replace all parts supplied with the kit (especially gaskets) can result in poor performance later.

Some carburetor manufacturers supply overhaul kits for three basic types: minor repair; major repair; and gasket kits. Basically, they contain the following:

Minor Repair Kits:


All gaskets
 
Float needle valve
 
All diagrams
 
Spring for the pump diaphragm
 

Major Repair Kits:


All jets and gaskets
 
All diaphragms
 
Float needle valve
 
Pump ball valve
 
Float
 
Complete intermediate rod
 
Intermediate pump lever
 
Some cover hold-down screws and washers
 

Gasket Kits:


All gaskets
 

After cleaning and checking all components, reassemble the carburetor, using new parts and referring to the exploded view. When reassembling, make sure that all screws and jets are tight in their seats, but do not overtighten as the tips will be distorted. Tighten all screws gradually, in rotation. Do not tighten needle valves into their seats; uneven jetting will result. Always use new gaskets. Be sure to adjust the float level when reassembling.

Disassembly

See Figures 13 through 25

  1. Remove the carburetor from the vehicle. Refer to the necessary procedure located earlier in this section.
  2.  



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Fig. Fig. 13: Primary vacuum break removal



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Fig. Fig. 14: Secondary vacuum break removal



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Fig. Fig. 15: Use pliers to remove the pump rod clip

  1. Mount the assembly in a holding fixture (special tool J-9787 or equivalent). Without the use of the holding fixture, it is possible to damage the throttle valves.
  2.  
  3. Remove 3 attaching screws that hold the idle speed control/primary vacuum break to the carburetor.
  4.  
  5. Remove the idle speed control, vacuum break and bracket as an assembly.
  6.  
  7. Remove the secondary vacuum break and bracket assembly attaching screws from the throttle body. Then rotate the assembly to disengage the vacuum break link.
  8.  

Do not immerse the idle speed control or vacuum break units in any type of carburetor cleaner.

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Fig. Fig. 16: The intermediate choke rod linkage is secured by a retainer clip



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Fig. Fig. 17: The mixture control solenoid is secured by screws



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Fig. Fig. 18: Air horn removal



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Fig. Fig. 19: Air horn components

  1. To remove the air horn assembly, remove the clip from the hole in the pump rod. Remove the choke rod and plastic bushing from the choke lever. Remove the three mixture control solenoid screws, then lift the solenoid out of the air horn.
  2.  
  3. Remove the fast idle cam rod from the choke lever by rotating the rod to align the notch on the rod with the small slot in the lever.
  4.  
  5. To remove the float bowl assembly, remove the air horn gasket. Remove the pump plunger from the pump well. Remove the TP sensor and connector assembly from the float bowl. Remove the spring from the bottom of the TP sensor well in the bowl.
  6.  



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Fig. Fig. 20: The Throttle Position (TP) sensor is positioned in the float bowl



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Fig. Fig. 21: Float bowl components



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Fig. Fig. 22: Bowl plastic insert removal

  1. Remove the plastic filler block over the float valve. Remove the float assembly and float valve by pulling up on the hinge pin.
  2.  
  3. Remove the plastic filler block insert from the float bowl cavity.
  4.  
  5. Using a special removal tool or a wide-blade screwdriver that fully fits the slots on the top of the float valve seat and the extended metering jet, remove the float valve seat (with the gasket) and the extended metering jet from the float bowl. Do not remove or change the adjustment of the small calibration screw located deep inside the metering jet.
  6.  
  7. Remove the plastic retainer holding the pump discharge spring and check ball.
  8.  
  9. Remove the fuel inlet nut, gasket, check valve filter assembly and spring.
  10.  



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Fig. Fig. 23: Metering jet and float valve seat locations



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Fig. Fig. 24: Remove the screws securing the throttle body



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Fig. Fig. 25: Idle mixture needle plug removal

  1. Unfasten the 4 throttle body-to-bowl attaching screws, then remove the throttle body assembly. Remove the throttle body-to-bowl insulator gasket.
  2.  

Cleaning and Inspection
  1. Thoroughly clean all metal parts and blow dry with compressed air. Make sure all fuel passages and metering parts are free of burrs and dirt. Do not pass drills or wires through the jets or passages
  2.  
  3. Inspect the upper and lower surfaces of the carburetor castings for damage.
  4.  
  5. Inspect the holes in the levers for excessive wear. Inspect the plastic bushings in the levers for damage, then replace as required.
  6.  

Assembly

See Figures 26, 27 and 28

  1. To install the throttle body, hold the primary throttle lever wide open, install the lower end of the pump rod in the throttle lever by aligning the notch on the rod with the slot in the elver. The end of the rod should point outward toward the throttle lever.
  2.  
  3. Install a new throttle body-to-bowl insulator gasket over the 2 locating dowels on the bowl.
  4.  
  5. Rotate the fast idle cam so that the steps face the fast idle screw on the throttle lever when properly installed, install the throttle body making certain it is properly located over the dowels on the float bowl. Install the screws and washers, then tighten them evenly to secure.
  6.  
  7. Place the carburetor assembly on a suitable holding fixture. Install the fuel inlet filter spring, check valve.filter assembly, new gasket and the inlet nut. Tighten the fuel filter inlet nut to 18 ft. lbs. (24 Nm).
  8.  

Tightening the fuel filter inlet nut beyond the specifications can damage the nylon gasket, causing a fuel leak.

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Fig. Fig. 26: Exploded view of the choke assembly



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Fig. Fig. 27: Air horn screw tightening sequences



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Fig. Fig. 28: Be sure to properly position the mixture control solenoid seal and retainers

  1. Install the choke housing on the throttle body, making sure the raised boss and locating lug on the rear housing fit into the recesses in the float bowl casting.
  2.  
  3. Install the intermediate choke shaft, lever and rod assembly in the float bowl by pushing the shaft through from the throttle lever side.
  4.  
  5. Install the choke coil lever inside the choke housing onto the flats on the intermediate choke shaft.
  6.  
  7. Instal the pump discharge steel check ball and spring in the passage next to the float chamber.
  8.  
  9. Insert the end of a new plastic retainer into the end of the spring, then install the retainer in the float bowl.
  10.  
  11. Using a special installation tool or a wide-bladed screwdriver that fully fits the slots on the top of the float valve and the extended metering jet, install the float valve seat (with gasket) and the extended metering jet. Tighten the seat and jet securely.
  12.  
  13. Place the plastic filler block insert into the blow cavity.
  14.  
  15. Install the float valve onto the float arm by sliding the float lever under the pull clip.
  16.  
  17. Install the float hinge pin into the float arm with the end of the loop of the pin facing the pump well. Install the float assembly by aligning the valve in the seat and float hinge pin into the locating channels in the float bowl. Adjust the float lever, as outlined earlier in this section.
  18.  
  19. Install the plastic filler block over the float valve, pressing downward until properly seated. Install the TP sensor return spring in the bottom of the well in the float bowl.
  20.  
  21. Install the TP sensor and electrical connector assembly.
  22.  
  23. Install the air horn gasket on the float bowl, locating gasket over the 2 dowel locating pins on the bowl. Install the pump return spring and plunger assembly in the pump well.
  24.  
  25. Rotate fast idle cam to the full Up position and tilt the air horn assembly to engage the lower end of fast idle cam rod in slot in the fast idle cam and install pump rod end into the pump lever; carefully lower the air horn assembly onto float bowl, guiding pump plunger stem through seal in air horn casting. DO NOT FORCE AIR HORN ASSEMBLY ONTO THE BOWL.
  26.  
  27. Fasten the 7 air horn to bowl attaching screws and lockwashers following proper installation location and tightening sequence. All air horn screws must be tightened EVENLY.
  28.  
  29. Install new retainer clip through hole in end of pump rod extending through pump lever, making sure clip is securely locked in place.
  30.  
  31. Install mixture control solenoid (spacer and rubber seal) on air horn, carefully aligning solenoid stem with recess in bottom of bowl.
  32.  
  33. Secure the plastic bushing in the hole in the choke lever, making sure the small end of the bushing faces the retaining clip when installed. Retain the rod with a new clip.
  34.  
  35. Install secondary side vacuum break assembly.
  36.  
  37. Install primary side vacuum break assembly (with idle speed control and bracket).
  38.  
  39. As outlined earlier in this section, install the carburetor.
  40.  

 
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