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Air Intake Control System Acura Integra I

Testing & Diagnostics 9 illustrations ~1049 words

DESCRIPTION

The air intake control system supplies air for all engine needs. The system consists of the air cleaner, air intake pipe, throttle body, Electronic Idle Control Valve (EICV), throttle angle sensor, fast idle mechanism and intake manifold.

On Legend Coupe with 2.7L engine, a by-pass control system is incorporated into the intake system. Two air paths are provided in the intake manifold to allow selection of the intake path length to vary for different engine operations. A long path is used for high torque at low RPM. A shorter path is used for high power at high RPM.

THROTTLE CABLE

  1. Check that throttle cable operates properly with no binding or sticking. Check throttle cable free play at throttle linkage. Cable free play should be 0.40-0.50" (10-12 mm). If free play is not within specification, loosen lock nut and turn adjusting nut until free play is at specification. (Scheme 5)
  2. With cable properly adjusted, check throttle valve to ensure it opens fully when accelerator is depressed. Check throttle valve to ensure it returns when accelerator is released.

Scheme 5

Scheme 5
Scheme 5

THROTTLE BODY

  1. Start engine. Warm engine to normal operating temperature (when cooling fan comes on). Disconnect vacuum hose (to canister) from top of throttle body. Connect a vacuum gauge to throttle body. (Scheme 6) Engine speed should be set at idle.
  2. Check vacuum gauge when throttle is opened slightly from idle that gauge reads vacuum. If gauge reads no vacuum, check canister port. If port is clogged, clean port with carburetor cleaner. Stop engine. Check that throttle cable operates properly without binding or sticking. Replace throttle body if there is excessive play in throttle valve shaft or if shaft is binding or sticking.

Scheme 6

Scheme 6
Scheme 6

DASHPOT SYSTEM

Note. On Integra models, a dashpot is used only with manual transmission.

  1. Check vacuum lines for proper connection, leaks, cracking or clogging. Disconnect vacuum hose from dashpot diaphragm and connect a vacuum pump to hose. (Scheme 7), (Scheme 8), (Scheme 9) or (Scheme 10). Apply 10 in. Hg vacuum, and check that vacuum releases slowly. If vacuum holds or releases quickly, replace dashpot check valve and retest.
  2. Connect vacuum pump to dashpot diaphragm. Apply 10 in. Hg vacuum. Check that diaphragm rod pulls in and holds vacuum. If vacuum does not hold or diaphragm rod does not move, replace dashpot diaphragm and retest.

Scheme 7

Scheme 7
Scheme 7

Scheme 8

Scheme 8
Scheme 8

Scheme 9

Scheme 9
Scheme 9

Scheme 10

Scheme 10
Scheme 10

Scheme 11

Scheme 11
Scheme 11

Scheme 12

Scheme 12: BY-PASS CONTROL SYSTEM
Scheme 12: BY-PASS CONTROL SYSTEM

Scheme 13

Scheme 13
Scheme 13
  1. Check by-pass valve shaft for binding, sticking and smooth movement. Ensure by-pass valve is in close contact with stopper when by-pass valve is fully open. Ensure by-pass valve is in close contact with full close screw when by-pass valve is fully closed. (Scheme 12)
  2. Clean linkage and shafts with carburetor cleaner if fault is found. Start engine and allow to idle. Remove No. 2 vacuum hose from by-pass control diaphragm and attach a vacuum gauge to hose. (Scheme 11) Check for vacuum.
  3. If no vacuum is present in step 2), remove No. 12 vacuum hose from vacuum tank and check for vacuum at tank. If vacuum is present at tank, proceed to step 7). If no vacuum is present at tank, check vacuum line between tank and intake manifold. Repair as necessary and recheck.
  4. If vacuum is present in step 2), raise engine speed to 4000 RPM and check vacuum gauge. If vacuum is present, proceed to step 11). If no vacuum is present, connect No. 2 vacuum hose and disconnect No. 7 vacuum hose from by-pass control diaphragm. Attach vacuum gauge and check for vacuum at idle.
  5. If no vacuum is present, proceed to step 13). If vacuum is present, raise engine speed to 3500 RPM and check for vacuum. If no vacuum is present, system is okay. If vacuum is present, proceed to step 6).
  6. If vacuum is present at 3500 RPM, disconnect solenoid connector at firewall and check again for vacuum. (Scheme 13) If vacuum is now present, check Green wire between ECU terminal No. B3 and solenoid connector. If wire is okay, replace by-pass solenoid valve B. If no vacuum is present, replace ECU with known good one and check system again. Replace ECU if necessary.
  7. If vacuum is present at tank in step 3), disconnect solenoid connector at firewall. Measure voltage between Black/Yellow terminal and Red/Blue terminal. If battery voltage is present, replace by-pass control solenoid valve A. If no voltage is present, proceed to step 8).
  8. If no battery voltage is present in step 7), measure voltage between Black/Yellow terminal and body ground. If no battery voltage is present, repair Black/Yellow wire between connector and fuse. If battery voltage is present, proceed to step 9).
  9. If battery voltage is present at step 8), turn ignition switch "OFF". Attach System Checker Harness (07999-PD6000A), between ECU and solenoid connector. Check for continuity between Red/Blue wire and ECU terminal A14. (Scheme 13)
  10. If no continuity is present, repair open in Red/Blue wire between ECU and connector. If continuity is present, connect a known good ECU and recheck. If voltage is now present, replace ECU.
  11. If vacuum is present in step 4), disconnect solenoid connector at firewall. If vacuum is now present, check Red/Blue wire. If wire is okay, replace by-pass control solenoid valve A. If no vacuum is present, proceed to step 12).
  12. If no vacuum is present in step 11), connect a known good ECU and recheck. If fault is not present, replace ECU.
  13. If no vacuum is present in step 5), disconnect solenoid connector at firewall. Check for battery voltage between Black/Yellow terminal and Green terminal. If battery voltage is present, replace by-pass control solenoid valve B. If no voltage is present, proceed to step 14).
  14. If no voltage is present, measure voltage between Black/Yellow terminal and body ground. If battery voltage is not present, repair open in Black/Yellow wire between connector and fuse. If battery voltage is present, proceed to step 15).
  15. If battery voltage is present, turn ignition switch "OFF". Connect System Checker Harness (07999-PD6000A), between ECU and connector. Check for continuity of Green terminal and ECU connector terminal B3. If no continuity is present, repair open in Green wire. If continuity is present, proceed to step 16).
  16. If continuity is present, connect a known good ECU and recheck. If voltage is present, replace ECU.

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