Firebird V6-191 3.1L (1990)
Ignition Control Module: Customer Interest
Engine - Cold Start Stall/Hesitation/Idle Roll
Bulletin Number:
91-6-32
Reference Number:
136505
Publish Date:
3/91
Subject:
COLD START STALL/HESITATION IDLE ROLL AND UPSHIFT SAG (DIAGNOSTICS, NEW HEI MODULE AND MEMCAL)
Models
Affected:
1990-91 FIREBIRD MODELS W/3.1
Condition:
Customers may experience Cold Start Stall and/or Hesitation, Idle Roll and/or 1-2 Upshift Sag with their 1990-91 Firebird model.
Cause:
System and component variability and electromagnetic interference.
Correction:
If any of the subject conditions are found, complete the following procedure:
1.
Perform diagnostics, per Section 6E of the Service Manual. Make any adjustments as required, or replace any defective parts associated with
the above conditions.
2.
For vehicles built prior to the VIN breakpoints indicated below, replace the High Energy Ignition (HEI) module with a new P/N 16140039,
and install a new Mem-Cal from the table, using the Service Manual and attached procedure.
VIN BREAKPOINTS
FEDERAL
ML241599
CALIFORNIA
ML241869
Broadcast
Scanner
Part
Code
I.D.
Number
Description
AYCH
4261
16164296
MEM-CAL (FED.)
AYCF
4251
16164292
MEM-CAL (CALIF.)
A.
Pull the underhood Electronic Control Module (ECM) continuous power fuse or disconnect the battery and leave it disconnected for at
least 1 minute.
B.
Remove existing Mem-Cal and install a new service Mem-Cal per the latest service procedure.
C.
Restore the battery power and place air conditioning controls (if equipped) in the "Off" position.
D.
Firmly apply the parking brake and block the drive wheels. Start the engine, and shift the transmission to "Drive".
E.
Allow the engine to run until the engine cooling fan has cycled once, or a maximum of 10 minutes.
F.
Turn the ignition key to the "Off" position for at least 5 seconds.
G.
Start the engine, and shift the transmission to "Drive".
H.
Allow engine to run for at least 5 minutes.
3.
If the installation of the new parts does not eliminate the driveability conditions then the ECM harness and the electrical harness (near the coil
bracket) should be inspected for chafing and repaired as required.
Parts are currently available from GMSPO.
Labor Operation Number
: T1707
