Suzuki Samurai/Sidekick/Tracker 1986-1998 Repair Guide

Exhaust Gas Recirculation (EGR) System

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OPERATION



The Exhaust Gas Recirculation (EGR) system reduces the emission Oxides of Nitrogen (NOx) into the atmosphere by rerouting exhaust gas back into the intake manifold. The incoming charge of exhaust gas dilutes the air/fuel mixture entering the cylinders, and, thereby, reduces peak combustion temperature. Lower peak combustion temperatures result in lower levels of NOx.

The EGR system is controlled by vacuum and the Engine Control Module (ECM), based on engine speed, temperature and load.

Carbureted Models

See Figure 1

The EGR system used on 1986-89 Samurai vehicles is composed of the EGR modulator, the EGR valve, a Bi-Metal Vacuum Switching Valve (BVSV), and the Three-Way Solenoid Valve (TWSV).

The EGR system is controlled largely by vacuum as follows: the BVSV is mounted in the vacuum line leading from the intake manifold to the EGR modulator, and threaded into the coolant passage of the intake manifold. The BVSV's main function is to sense engine coolant temperature, and to open or close based on the coolant temperature. When the engine coolant temperature is too cold, the BVSV closes, thereby stopping engine vacuum from reaching the EGR modulator.



Click image to see an enlarged view

Fig. Fig. 1: Exhaust Gas Recirculation (EGR) system schematic-1986-89 Samurai and Sidekick models

The EGR modulator senses the amount of backpressure in the exhaust valve, and, in turn, controls the amount of vacuum applied to the EGR valve.

Mounted in the vacuum line from the EGR modulator to the EGR valve, is the TWSV. The main function of this component is to block vacuum from reaching the EGR valve when the ECM deems it necessary (depending on transmission gear and operation of the heating-air conditioning system). Therefore, the vacuum must travel through the BVSV, through the EGR modulator and through the TWSV before it reaches the EGR valve.

If vacuum is allowed to reach the EGR valve, it pulls the EGR valve pintle up and off of its seat, thereby allowing exhaust gas to flow into the intake manifold.

Fuel Injected Models
1.3L AND 1.6L ENGINES
See Figure 2

The EGR system used on Sidekick, Tracker, X-90 and 1990-95 Samurai vehicles is composed of the EGR modulator, the EGR valve, the EGR Temperature (EGRT) sensor, and the EGR Solenoid Vacuum (EGR SV) valve.

On newer vehicles, the EGR modulator is referred to as the EGR pressure transducer. Both components are identical and perform the same job, regardless of which name you decide to call them.

The EGR system is controlled largely by vacuum as follows: the EGR SV valve is mounted in the vacuum line leading from the intake manifold to the EGR modulator. The EGR SV valve's main function is to open or close based on signals from the Engine Control Module (ECM), thereby allowing or preventing (respectively) engine vacuum from reaching the EGR modulator. The ECM sends signals to the EGR SV valve depending on engine temperature, barometric pressure, engine speed, and engine load.



Click image to see an enlarged view

Fig. Fig. 2: Exhaust Gas Recirculation (EGR) system schematic-1990-98 Sidekick, Tracker, X-90 and Samurai models

The EGR modulator senses the amount of backpressure in the exhaust valve, and, in turn, controls the amount of vacuum applied to the EGR valve. Therefore, the vacuum must travel through the EGR SV valve and through the EGR modulator before it reaches the EGR valve.

If vacuum is allowed to reach the EGR valve, it pulls the EGR valve pintle up and off of its seat, thereby allowing exhaust gas to flow into the intake manifold.

The 1990-95 California models are equipped with the EGRT sensor, which is used by the ECM to monitor EGR valve operation. The operation of the EGR valve is monitored by the change in temperature in the exhaust gases.

The 1996-98 models are equipped with two additional components, both of which are used for EGR system diagnosis by the ECM. The Manifold Differential Pressure (MDP) sensor and the EGR Bypass (EGRB) valve (mounted in the vacuum line between the EGR modulator and the EGR valve. The ECM uses these components to compare the pressure in the EGR system with the pressure in the intake manifold to check for a blockage.

1.8L ENGINE

See Figure 3

The EGR system used on Sidekick Sport models is composed of only the EGR valve and exhaust gas piping. The EGR valve is controlled solely by the ECM, unlike the other EGR systems covered in this guide. The ECM decides when to initiate EGR system function based on input information from the Camshaft Position (CMP) sensor, Engine Coolant Temperature (ECT) sensor, Mass Air Flow (MAF) sensor and the Vehicle Speed Sensor (VSS).

The EGR system is turned off when the engine is too cold, the throttle valve is opening less than specification calls for, when the engine is operated under heavy load, and when the vehicle is stopped.



Click image to see an enlarged view

Fig. Fig. 3: Exhaust Gas Recirculation (EGR) system schematic-Sidekick Sport models

COMPONENT TESTING



Carbureted Models
EGR SYSTEM INSPECTION
See Figures 4 and 5

Before commencing with this procedure, ensure that you are not at an altitude of more than 4000 ft. (16m) and that the gear shift lever is in Neutral. If you are at an altitude of more than 4000 ft. (16m), be sure to detach the HAC wiring harness connector.


CAUTION
During the following procedure, it may be necessary to wear gloves to avoid burning your finger when the EGR valve becomes hot.

  1. If the engine is hot, allow the engine to cool down to room temperature.
  2.  



Click image to see an enlarged view

Fig. Fig. 4: With the engine cold and idling, feel the EGR valve diaphragm to ensure that the valve is not operating



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Fig. Fig. 5: When the engine is warm, rev the engine and ensure that the diaphragm moves toward (1) during acceleration and toward (2) during deceleration

  1. Start the engine and allow it to idle. Check that the EGR valve diaphragm is not operating by touching it with your finger.
  2.  
  3. Warm the engine up to normal operating temperature, then race the engine. While racing the engine, ensure that the diaphragm moves toward the wide end of the EGR valve (1) during acceleration and toward the narrow end of the valve (2) during deceleration.
  4.  
  5. If the EGR valve does not function as indicated, test the EGR system components to find the defective item.
  6.  

HOSES

Inspect all EGR system hoses for loose connections, leaks, clogs, and deterioration. Replace any faulty hoses with new ones.

EGR VALVE
  1. Detach the vacuum hose from the TWSV.
  2.  
  3. Attach a hand-held vacuum pump to the disconnected end of the vacuum hose.
  4.  
  5. Slowly apply vacuum to the EGR valve diaphragm. The EGR valve diaphragm should move smoothly as vacuum is applied, and it should hold its position (open) when more than 7.9 in. Hg (1 cmHg) vacuum is applied.
  6.  
  7. If the diaphragm did not move smoothly, or did not hold its position, replace the EGR valve.
  8.  
  9. Reattach the vacuum hose to the TWSV.
  10.  

BI-METAL VACUUM SWITCHING VALVE (BVSV)

See Figures 6 and 7

This procedure can also be performed by removing the BVSV and warming it up in a pot of water on a stove.

  1. Allow the vehicle to sit, unused, overnight so that the engine is completely cold (below 127°F/53°C).
  2.  
  3. Disconnect and label the vacuum hoses from the BVSV.
  4.  
  5. Attach two new hoses to the BVSV nipples.
  6.  
  7. Blow through the hose attached to the upper BVSV nipple (3) and ensure that air does NOT come out of the end of the other hose (4).
  8.  



Click image to see an enlarged view

Fig. Fig. 6: If the BVSV is removed from the vehicle, place it in a container of cold water and attempt to blow air through the top valve nipple-no air should exit from the lower valve nipple



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Fig. Fig. 7: Warm the water up and attempt, once again, to blow air through the upper valve nipple-the air should now exit from the lower nozzle

  1. Start the engine and allow it to warm up (above 149°F/65°C).
  2.  
  3. Once again, blow through the hose attached to the upper BVSV nipple (3) and ensure that air DOES come out of the end of the other hose (4).
  4.  
  5. If the BVSV does not function as indicated, replace it with a new one.
  6.  
  7. Reattach the original vacuum hoses to the BVSV.
  8.  

EGR MODULATOR

See Figure 8

  1. Remove the modulator from the vehicle.
  2.  
  3. Remove the cap and inspect the filter for contamination and/or damage. Use compressed air to blow the dirt out of the filter.
  4.  
  5. Reassemble the filter and cap, then plug one of the side hose nipples and blow compressed air into the other side nipple. Ensure that the air passes through the air filter and out the modulator cap.
  6.  



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Fig. Fig. 8: Before testing the modulator, remove and clean the filter element

  1. Connect a hand-held vacuum pump to one of the side hose nipples and plug the other side nipple with your finger, or a vacuum cap. Blow air into the downward pointing nipple and apply vacuum to the one side nipple. Ensure that the modulator holds the vacuum applied with the hand-held pump.
  2.  
  3. If the modulator does not function as indicated, replace it with a new one.
  4.  

THREE-WAY SOLENOID VALVE (TWSV)

See Figures 9 and 10

  1. Detach the two vacuum hoses from the TWSV.
  2.  
  3. Attach two new vacuum hoses to the TWSV, then attempt to blow air through hose 1 (refer to the accompanying illustration). The air should exit from the other hose (2) and NOT out of the filter (3).
  4.  
  5. Detach the wiring harness connector from the TWSV, then connect a 12 volt DC battery to the two terminals to energize the TWSV.
  6.  
  7. Once again, attempt to blow air through hose 1. The air should now exit through the filter and NOT from hose 2.
  8.  
  9. If the TWSV did not function as indicated, replace it with a new one.
  10.  



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Fig. Fig. 9: To test the TWSV, detach the wiring harness connector from the valve, then blow air into the upper valve hose-the air should exit from the lower hose



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Fig. Fig. 10: Apply 12 volts DC current to the valve and once again blow air into the upper vacuum hose-the air should now exit from the filter and NOT from the lower hose

Fuel Injected Models-1.3L and 1.6L Engines
EGR SYSTEM INSPECTION

Before commencing with this procedure, ensure that you are not at an altitude of more than 8,10 ft. (1000m), that the atmospheric pressure is 8 in. Hg (585 mmHg) or higher, that the transmission is in Neutral, that the parking brake lever is engaged, and that the VSS, ECT sensor, TP sensor and MAP sensor are in good operating condition.


CAUTION
During the following procedure, it may be necessary to wear gloves to avoid burning your finger when the EGR valve becomes hot.

  1. For 1994-96 models, perform the following:
    1. Raise and safely support the rear of the vehicle on jackstands so that rear wheels can spin freely.
    2.  
    3. Position the transfer case in 2H.
    4.  
    5. Start the engine and release the parking brake lever; the rear wheels should turn. If the wheels are not turning, have an assistant rotate one of the wheels during the test. This is necessary only on 1994-96 models since the ECM knows if the rear drive wheels are spinning or not; the EGR system will not function if the ECM thinks the vehicle is standing still.
    6.  

  2.  
  3. If the engine is hot, allow the engine to cool down to room temperature.
  4.  
  5. Start the engine, then while racing the engine to 3500 rpm or higher, check that the EGR valve diaphragm is not operating by touching it with your finger.
  6.  
  7. Warm the engine up to normal operating temperature, then race the engine to at least 3500 rpm. While racing the engine, ensure that the diaphragm moves toward the wide end of the EGR valve (1) during acceleration and toward the narrow end of the valve (2) during deceleration. (Refer to the accompanying illustration.) If the EGR valve does not function as indicated, test the EGR system components to find the defective item.
  8.  
  9. Keep the engine idling, then open the EGR valve by hand: the engine should either stop or reduce its speed. If neither occurs, the EGR passage is most likely clogged. Clean the passage and retest.
  10.  

HOSES

Inspect all EGR system hoses for loose connections, leaks, clogs, and deterioration. Replace any faulty hoses with new ones.

EGR VALVE
  1. Detach the vacuum hose from the EGR modulator.
  2.  
  3. Attach a hand-held vacuum pump to the disconnected end of the vacuum hose.
  4.  
  5. Slowly apply vacuum to the EGR valve diaphragm. The EGR valve diaphragm should move smoothly as vacuum is applied, and it should hold its position (open) when more than 7.9 in. Hg (1 cmHg) vacuum is applied.
  6.  
  7. If the diaphragm did not move smoothly, or did not hold its position, replace the EGR valve.
  8.  
  9. Reattach the vacuum hose to the EGR modulator.
  10.  

EGR MODULATOR

See Figure 11

  1. Remove the modulator from the vehicle.
  2.  
  3. Remove the cap and inspect the filter for contamination and/or damage. Use compressed air to blow the dirt out of the filter.
  4.  
  5. Reassemble the filter and cap, then plug one of the side hose nipples and blow compressed air into the other side nipple. Ensure that the air passes through the air filter and out the modulator cap.
  6.  
  7. Connect a hand-held vacuum pump to one of the side hose nipples and plug the other side nipple with your finger, or a vacuum cap. Blow air into the downward pointing nipple and apply vacuum to the one side nipple. Ensure that the modulator holds the vacuum applied with the hand-held pump.
  8.  
  9. If the modulator does not function as indicated, replace it with a new one.
  10.  

EGR SOLENOID VACUUM (EGR SV) VALVE

CAUTION
NEVER suck air through the EGR SV valve. Residual toxic gasoline fumes may be inhaled, which can cause severe internal injuries.

  1. With the ignitions witch OFF , detach the wiring harness connector from the EGR SV valve.
  2.  
  3. Using an ohmmeter, measure the resistance between the two EGR SV valve terminals. Resistance should be 33-39 ohms at 68°F (1°C) for 1990-93 models, 30-38 ohms at 68°F (1°C) for 1994-96 models, or 28-36 ohms at 68°F (1°C) for 1997-98 models. If the resistance of the EGR SV valve is not as specified, replace it with a new one.
  4.  



Click image to see an enlarged view

Fig. Fig. 11: The EGR SV valve is mounted on the front of the engine, next to the throttle opener vacuum switching valve

  1. Detach the EGR SV valve vacuum hoses from the EGR modulator and throttle body.
  2.  
  3. With the wiring harness connector still detached from the EGR SV valve, attempt to blow air through the EGR SV valve hose A (as indicated in the accompanying illustration). Air should emit from hose B.
  4.  
  5. Connect a 12 volt DC battery to the two EGR SV valve wiring harness terminals, then attempt to blow air through the valve again. Air should exit from the filter, NOT from hose B while it is energized.
  6.  
  7. If the valve does not function as indicated, replace it with a new one.
  8.  
  9. Reattach the EGR SV valve vacuum lines and wiring harness connector.
  10.  

EGR BYPASS (EGRB) VALVE

CAUTION
NEVER suck air through the EGRB valve. Residual toxic gasoline fumes may be inhaled, which can cause severe internal injuries.

  1. With the ignitions witch OFF , detach the wiring harness connector from the EGRB valve.
  2.  
  3. Using an ohmmeter, measure the resistance between the two EGRB valve terminals. Resistance should be 37-44 ohms at 68°F (1°C). Measure the resistance between the EGRB valve body and the wiring connector terminals; the resistance should be 1 megaohm or greater.
  4.  
  5. Detach the EGRB valve vacuum hoses from the EGR modulator and throttle body.
  6.  
  7. With the wiring harness connector still detached from the EGRB valve, attempt to blow air through the EGR SV valve hose A (as indicated in the accompanying illustration). Air should emit from hose B.
  8.  
  9. Connect a 12 volt DC battery to the two EGRB valve wiring harness terminals, then attempt to blow air through the valve again. Air should exit from the filter, NOT from hose B while it is energized.
  10.  
  11. If the valve does not function as indicated, replace it with a new one.
  12.  
  13. Reattach the EGRB valve vacuum lines and wiring harness connector.
  14.  

Fuel Injected Models-1.8L Engine

EGR SYSTEM INSPECTION

A scan tool, such as Suzuki scan tool with OBD-II cartridge, is necessary for this system inspection.

  1. Connect the scan tool to the DLC with the ignition switch OFF .
  2.  
  3. Start the engine and warm it up to normal operating temperature (176-62°F/80-100°C).
  4.  
  5. Clear Diagnostic Trouble Code (DTC), pending DTC, freeze frame data in ECM memory with the scan tool.
  6.  
  7. With the engine, and without depressing the accelerator pedal, open the EGR valve by using the MISC TEST mode.
  8.  
  9. In this state, the more the EGR valve opens, the lower the engine idle speed should drop. If the idle speed does not drop, the possible causes could be a clogged EGR gas passage, a stuck or faulty EGR valve, poor performance of the ECT sensor or TP sensor, or DTC's and/or pending DTC's are stored in ECM memory.
  10.  

EGR VALVE

See Figure 12

  1. Remove the EGR valve from the engine.
  2.  
  3. Measure the resistance between EGR valve terminals A and B, C and B, F and E, and D and E. All resistances should be between 1-9 ohms. If the one or more of the values measured is not within this range, replace the EGR valve with a new one.
  4.  
  5. Clean the carbon from the EGR valve gas passage.
  6.  



Click image to see an enlarged view

Fig. Fig. 12: EGR valve terminal identification for testing-Sidekick Sport models


WARNING
Do not use a sharp-edged implement to remove the carbon. Be careful not to damage the EGR valve, valve seat or rod.

  1. Inpsect the EGR valve, valve seat and rod for defects, such as cracks, bends or other damage. If any such damage is evident, replace the valve with a new one.
  2.  

MANIFOLD DIFFERENTIAL PRESSURE (MDP) SENSOR

Testing procedures for the Manifold Differential Pressure (MDP) sensor a covered later in this section, under electronic engine controls.

REMOVAL & INSTALLATION



Except 1.8L Engine
EGR VALVE
  1. Detach and label the vacuum hoses from the EGR valve.
  2.  
  3. Loosen the two EGR valve mounting bolts, then separate the valve from the intake manifold.
  4.  
  5. Remove and discard the old gasket.
  6.  
  7. Clean the EGR valve-to-intake manifold gasket mating surface of all carbon, dirt and old gasket material.
  8.  

To install:
  1. Position a new gasket on the intake manifold, then install the EGR valve. Tighten the EGR valve bolts evenly to 15 ft. lbs. (1 Nm).
  2.  
  3. Reattach the vacuum hoses to the valve.
  4.  

EGR MODULATOR

This component is also referred to as the EGR Pressure Transducer.

  1. Detach and label the vacuum hoses from the EGR modulator.
  2.  
  3. Disengage the modulator from the mounting clips.
  4.  

To install:
  1. Engage the modulator securely in the mounting clips.
  2.  
  3. Reattach the vacuum hoses to the modulator.
  4.  

BVSV, TWSV, EGR SV, AND EGRB VALVES
  1. Disconnect the negative battery cable.
  2.  
  3. Detach and label the vacuum hoses from the valve.
  4.  
  5. Disengage the wiring harness connector from the valve.
  6.  
  7. Loosen the two retaining screws, then separate the valve from the mounting bracket.
  8.  

To install:
  1. Position the valve on the mounting bracket, then install the retaining screws until snug.
  2.  
  3. Reattach the wiring harness connector in the valve, ensuring that the locking tab is fully engaged.
  4.  
  5. Connect the vacuum hoses to the valve.
  6.  
  7. Connect the negative battery cable.
  8.  

1.8L Engine

EGR VALVE
  1. Disconnect the negative battery cable.
  2.  
  3. Detach the EGR valve connection from the valve.
  4.  
  5. Loosen the EGR valve mounting bolts, then separate the valve from the intake manifold.
  6.  
  7. Remove and discard the old gasket.
  8.  
  9. Clean the EGR valve-to-intake manifold gasket mating surface of all carbon, dirt and old gasket material.
  10.  

To install:
  1. Position a new gasket on the intake manifold, then install the EGR valve. Tighten the EGR valve bolts evenly to 15 ft. lbs. (1 Nm).
  2.  
  3. Reattach the EGR valve connection to the valve.
  4.  
  5. Connect the negative battery cable.
  6.  

MANIFOLD DIFFERENTIAL PRESSURE (MDP) SENSOR

The removal and installation of this sensor is described later in this section.

 
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