Engine - Detonation

91nissan04

Classification: EM91-005

Section: ENGINE MECHANICAL

TECHNICAL BULLETIN NTB91-056


Models: 1990 300ZX

Date: MAY 30, 1991


1990 300ZX CRANK ANGLE SENSOR CAUSING DETONATION

(SPARK KNOCK)


APPLIED MODELS: 1990 300ZX, 300ZX TURBO


APPLIED VIN: Prior to:
JN1RZ24A-MX050007 (July 3, 1990)
JN1RZ26A-MX050002 (July 3, 1990)
JN1CZ24A-MX050001 (July 4, 1990)
JN1RZ24H-MX500223 (July 20, 1990)
JN1RZ26H-MX500046 (July 3, 1990)
JN1CZ24H-MX500082 (July 4, 1990)


SERVICE INFORMATION:


On some 1990 300ZX vehicles, customers may complain of engine detonation (spark knock). The incident may be caused by the initial ignition timing being excessively advanced. If the vehicle has this condition, it may be impossible to adjust the timing to the correct initial specification by turning the crank angle sensor.


The cylinder head assemblies of the incident vehicles may have been improperly machined. This results in the camshaft indexing peg and the crank angle sensor being off-center. The off-center condition allows excessive force to be applied to the indexing peg which results in damage to the peg. In most cases, but not all, the indexing peg on the camshaft will be damaged causing the incident of advanced ignition timing.

Crank Angle Sensor:

SERVICE PROCEDURE:


Check the crank angle sensor initial ignition timing using a timing light. Note: The CONSULT unit will not give initial timing. If the initial timing is incorrect, make the necessary adjustments.

Camshaft Indexing Peg:

If the initial ignition can not be set to the proper specification, check for damage to the indexing peg on the camshaft. Damage to the indexing peg will confirm the cause of the incident. In this case, it will be necessary to replace the cylinder head to resolve the incident. Replace the crank angle sensor and/or camshaft if necessary.


NOTE: Check Camshaft Indexing Peg, if peg is O.K. Camshaft may be reused.


Note: On some vehicles the incident of advanced ignition timing may not always result in a broken indexing peg. If the initial ignition timing is advanced and cannot be adjusted to the correct specification, then replace the parts as required.


PARTS INFORMATION:


PART NAME PART NUMBER

Camshaft 13020-F6515

Cylinder Head 11091-40P80

Crank Angle Sensor 23731-45V10


WARRANTY INFORMATION:


LABOR DESCRIPTION OP CODE PNC CS CT FLAT RATE

Replace left cylinder head AP15AA 11041 1M 03 15.2 hrs.

(TURBO)
17.5 hrs.
NOTE: Operation AP15AA includes labor time to install new camshaft and crank angle sensor.