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Installer Tech Tip: Engine Knocking Noise Just Above Idle on Nissan VG33E May Be Normal
If your customer complains of an engine knock just above idle from your rebuilt Nissan VG33E engine, you can tell them that the cause may be a normal pulsating noise coming from the EVAP purge
solenoid valve and piping (in the engine compartment) transferring into
the passenger cabin. However, use the following procedure to reduce the
1. Start and run the engine for at least one minute.
2. Use CONSULT-II to view the status of the “Closed Throttle Position Switch” (CTPS).
3. Set the Parking Brake, then perform the following;
For vehicles with an automatic transmission, with your foot on the brake, place the A/T gear selector in “D.”
For vehicles with a manual transmission, depress the clutch and select any gear.
4. While viewing CTPS status, open the throttle just enough to change the CTPS status from “On” to “Off.”
Note: This will allow the EVAP purge volume control solenoid valve to begin operating.
5. Listen closely for a slight “knocking” noise. If “knocking” noise is heard;
a. Put the transmission in “neutral” (M/T) or “park” (A/T).
b. Disconnect the electrical connector to the EVAP purge volume control solenoid valve. See Fig. 1.
c. Listen again for the “knocking” noise by repeating steps 3, 4 and 5.
If the “knocking” noise is still heard, this service bulletin does not
apply. Consult the appropriate service manual for further diagnosis.
If “knocking” noise is not heard, shut off the engine and proceed to step 6.
Remove the hose clamps from the EVAP purge hose. See Fig. 2
Remove the EVAP purge hose. See Fig. 2.
Note: Set aside the two purge hose clamps for use in step 8.
Install a vacuum tank and hose kit (P/N 14958-5S625). See Fig. 3
Note: Use the hose clamps set aside in step 7 to secure the replacement parts.
Reconnect the electrical connector to the EVAP purge volume control solenoid valve. See Fig. 1.
Repeat steps 3, 4 and 5 to verify the slight “knocking” noise is gone.
Technical service bulletin courtesy of Mitchell 1.
For additional information, visit www.mitchell1.com