Fuel - Throttle Chamber Deposits

Classification:
EF & EC93-014

Section:
Engine Fuel

Reference:
TECHNICAL BULLETIN NTB93-168

Models:
1990-93 300ZX

Date:
November 16, 1993

300ZX (Z32) DRIVEABILITY INCIDENTS
(THROTTLE CHAMBER DEPOSITS)

SERVICE INFORMATION

When servicing a customer's vehicle that has any of the following symptoms:

Idle speed fluctuation
Idle speed not to specification
Accelerator hard to push
Difficulty in accelerating smoothly from a stop (throttle/vehicle "jumpy")

Check the throttle chambers for deposits. If deposits are found, use the following procedure to clean them and to prevent deposits from recurring in the future:

SERVICE PROCEDURE

When a customer complains of any of the above symptoms, perform the following procedure:

1) Check for throttle chamber deposits.

Remove the air inlet ducts from the throttle chambers. Open the throttle valve and check for deposits with a light. If deposits are found, remove them with spray carburetor cleaner or another suitable cleaner.

2) Set the base idle speed.

Using CONSULT in "Work Support" mode (or by disconnecting the AAC valve), check the base idle, and adjust if necessary. See 1993 Z32 Service Manual pages EF & EC 33-35 (or other applicable manual) for procedure details.

3) Check engine oil level and correct if necessary.

It is important that the engine oil is not overfilled (above the "H" mark).

These three steps will eliminate many of the above customer complaints. Maintaining the proper engine oil level (not overfilled) will help prevent the recurrence of these complaints.

If the vehicle still exhibits the customer's complaint after following these steps, consult the Service Manual or TECHLINE for further assistance.