Engine - Spark Knock On Acceleration

91nissan02

Classification: EM91-004

Section: Engine Mech.

Reference: TECHNICAL BULLETIN NTB91-040



Models: 1990 300ZX

Date: April 11, 1991


1990 300ZX POSITIVE CRANKCASE VENTILATION VALVE NOISE


APPLIED MODEL: 1990 300ZX, 300ZX TURBO

APPLIED VIN: JN1RZ24A(*)018926 (June 7, 1990) 2-Seater
JN1RZ26A(*)012672 (June 6, 1990) 2+2
JN1CZ24A(*)006646 (June 8, 1990) Turbo
JN1RZ24H(*)500007 (July 2, 1990) 2-Seater
JN1RZ26H(*)500010 (June 27, 1990) 2+2
JN1CZ24H(*)500018 (July 2, 1990) Turbo

APPLIED ENGINE #: VG30-760463 (June 5, 1990)


SERVICE INFORMATION

On some 1990 300ZX vehicles, customers may complain of a spark knock (detonation) noise. The noise occurs when the vehicle is accelerating or the engine is "racing" under no load. The noise from the Positive Crankcase Ventilation (PCV) Valve can be checked by removing or pinching off the PCV hoses. If the noise is eliminated, then the cause must be related to the PCV valve.

If the noise is not eliminated, then, further investigation is required:
^ Check the type of gasoline used (the 300ZX requires "Premium Unleaded" fuel).
^ Check that the Crank Angle Sensor is reading the correct engine timing.
^ If the vehicle is equipped with an automatic transmission, refer to the TSB entitled, "Engine Detonation (Spark Knock)," (NTB90-097).

Figure 1:

SERVICE PROCEDURE

To eliminate the noise, the PCV valve and PCV hoses have been modified (Figure 1).


1. Remove and discard the original PCV valve and PCV hoses.

2. Attach the Countermeasure PCV valve and coordinate hoses.


PARTS INFORIXATION


Part Name Countermeasure Part Former Part

Valve Assly-Control 11810-40P00 11810-30P00
Hose-Blow by 11823-30P01 11826-30P01
Hose-Blow by 11823-3OP11 11826-30P11

NOTE: The 300ZX requires 2 of each part (listed above).

WARRANTY INFORMATION

PNC CS CT OP CODE FLAT RATE TIME
11810 1M 31 AT42AA 0.3 Hr.