Poor Cold Start/A/C Performance, and Hesitation or Sag
File In Section: 6E - Engine Fuel & EmissionBulletin No.: 47-65-17
Date: October, 1994
Subject:
Poor Cold Start, Hesitation or Sag and/or Poor Air Conditioner Performance (Replace MEMCAL)
Models:
1990-93 Buick Century
1990-93 Oldsmobile Cutlass Ciera with 3300 V6 Engine (VIN N - RPO LG7)
Condition
Two conditions addressed with the same MEMCAL:
1. Some vehicles may exhibit a condition described as a "cold start-stall," "hesitation," or "sag" when the engine coolant is between 36~F to 111~F (2~C to 44~C).
2. Some owners may experience inadequate air conditioner performance when driving at a steady speed and throttle position, between 24 to 64 MPH, when the cruise control is not being used.
Cause
Two causes, depending on the condition being addressed:
1. Variability in volatility of fuels may cause the air/fuel ratio to be too lean upon cold start ups (see statement 1 under Condition).
2. The MEMCAL software operating system may cause the air conditioning compressor to switch off during extended steady speed and throttle position while driving without using cruise control (see statement 2 under Condition).
Correction
One MEMCAL corrects both conditions:
1. If conditions outlined in Section 6E3-B of appropriate service manuals are not causing the hesitation or sag, a service MEMCAL is available to slightly enrich the cold start air/fuel ratio, compensating for the variance in volatility of different fuels. NO OTHER DRIVEABILITY ISSUES ARE ADDRESSED WITH THIS MEMCAL (see statement 1 under Condition).
2. Verify, by road testing, the inadequate air conditioner performance concern occurs only between 24 to 64 MPH:
^ Steady speed and throttle position
^ Cruise off
If the road test confirms the comment, replace the MEMCAL. This MEMCAL will not correct for inadequate air conditioner performance occurring above 64 MPH and/or below 24 MPH, including idle. Also, if inadequate air conditioning occurs with the cruise control on (under any condition), no correction will be made by using this MEMCAL (see statement 2 under Condition).
Service Information
Use the procedure in Section 6E3 in the service manual for MEMCAL replacement.
Parts Information
Parts are expected to be available from GMSPO on October 3, 1994.
Warranty Information
Labor Operation Labor Time
J6364 0.6 Hour