Engine Controls - Spark Knock During Engine Start

Classification:
EC98-013

Reference:
NTB98-050

Date:
June 15, 1998

1995-98 MAXIMA SPARK KNOCK DURING ENGINE START

APPLIED VEHICLE:
1995-98 Maxima (A32)

APPLIED DATE:
Vehicles built before March 1998

SERVICE INFORMATION

If a 1995-98 Maxima has a spark knock at the moment the ignition key is released from the "start" position during a hot restart, the cause may be excessive ignition advance. The incident described would occur within about 1 minute after stopping the engine. The duration of the noise would be less than 1 second.

A countermeasure ECM is available to resolve this incident. Use the following procedure to diagnose and repair this incident.

This condition is NOT the same as a spark knock that may occur at high ambient temperatures/low humidity conditions (see NTB97-058 for further information).

SERVICE PROCEDURE

1. Confirm with the customer that the correct grade of fuel is used (unleaded 91 AKI minimum). If not, inform the customer that using premium gasoline will reduce the level of spark knock. Recommend that the customer begin using it and return the vehicle to the customer.

2. Confirm the incident as follows:

A. Test drive the vehicle until it has reached full operating temperature.

B. Stop the engine and immediately restart within 10 seconds.

C. Listen carefully for spark knock at the moment the ignition key is released from the "start" position.

NOTE:
It is helpful to perform this step in a relatively quiet location.

1) If the spark knock is heard, install the appropriate countermeasure ECM from the Parts Information table.

2) If you cannot duplicate the incident, return the vehicle to the customer with the fuel grade recommendation from step 1 above.

3. After installation, use the above procedure to verify the incident has been resolved.





PARTS INFORMATION

CLAIMS INFORMATION





Submit a Primary Failed Part (PP) line using the claims coding as shown.