Poor Cold Performance - Replace Engine Controller (18-86-91)
Publication date: 1991-09-09Reference number: 18-86-91
POOR COLD PERFORMANCE - REPLACE ENGINE CONTROLLER
TECHNICAL SERVICE BULLETIN
COLD ENGINE POOR PERFORMANCE/SAG OR SURGE ON ACCELERATION
Model 1991-92 (BB) Premier Equipped With Single Board Engine Controller (SBEC II)
Group Engine Performance
Bulletin No. 18-56-91
Date September 9, 1991
S ymptom Cold Engine Poor Performance/Sag Or Surge On Acceleration
SERVICE INFORMATION
1991 vehicles built after MDH 10-08-XX are equipped with a SBEC II. These vehicles can be identified by an eight in the twelfth position of the VIN.
SYMPTOM/CONDITION:
The vehicle will exhibit the two following conditions. First, the engine will sag and/or pop back during the first aggressive throttle tip in. This will happen within the first ten seconds of a cold engine start up when the ambient temperature is between approximately 60°F - 90°F (15°C - 32°C). Second, with the engine fully warm, the vehicle will exhibit a surge while traveling 30-40 MPH (50-65 KM/H).
DIAGNOSIS:
Verify that the system is functioning as designed using the appropriate diagnostic test procedure.
| QTY. | DESCRIPTION | PART NUMBER |
|---|---|---|
| 1 | Engine Controller | 4605101 |
| 1 | Authorized Modification Label | 4275086 |
REPAIR PROCEDURE:
This procedure involves replacement of the engine controller (SBEC) with a revised engine controller.
- Replace the original engine controller with the revised engine controller (4605101).
- Type an Authorized Modification Label, PN 4275086 as shown in Figure 1 and attach near the VECI label.