Ignition/Engine Controls - Spark Knock on Acceleration
01-026/031998-2000 B3000
SPARK KNOCK/PING/DETONATION NOISE DURING ACCELERATION
Note:
This bulletin supersedes the following TSB(s): 01-017/01 Please update your records accordingly.
BULLETIN NOTE
This bulletin supersedes 01-017/01 and 01-017/00. The REPAIR PROCEDURE has changed.
APPLICABLE MODEL(S)/VINS
1998-00 B-3000 with build dates before 2/21/00.
DESCRIPTION
Some vehicles may exhibit a spark knock sound or "ping" type noise during acceleration. This maybe caused by the ignition coil and the Powertrain Control Module (PCM).
Customers having this concern should have their vehicle repaired using the following procedure.
REPAIR PROCEDURE
1. Verify customer concern.
^ Verify that noise is coming from combustion chamber by removing all fuel from tank and replacing it with two (2) gallons of 94 octane fuel.
2. Road test vehicle.
^ If noise is still present this bulletin does not apply. Return original fuel to vehicle and continue with engine or other mechanical noise diagnostics.
^ If noise was reduced or eliminated, return original fuel to vehicle and proceed to STEP 3.
3. Inspect build code stamped on top of ignition coil:
^ If first four (4) digits of build code are between the range of 7001 to 9213, replace the coil with a revised coil and proceed to STEP 4.
^ If build date does NOT fall between 7001 to 9213, do not replace coil and proceed to STEP 4.
NOTE:
Verify replacement coil has a build date outside of the 7001-9213 range prior to installation. Only use coils that DO NOT fall in this range.
4. Locate the PCM Catch Word on the firewall adjacent to the PCM, or on white tag on PCM. Using the Catch Word, obtain and replace the PCM (refer to PCM Reference Chart in PARTS INFORMATION section), and proceed to STEP 5.
NOTE:
1998 to 2000 B3000's built before 2/21/00 do not allow PCM reflashing using WDS. When attempting to reflash the PCM, the following message will be displayed:
"THIS VEHICLE IS FITTED WITH PCM HARDWARE VERSION(S) ML2-8C2A. REQUIRED HARDWARE VERSION TO CONTINUE: ML2-8E2A"
This means that the PCM must be replaced as described in step 4 above before you can reflash with the latest calibration using WDS.
NOTE:
^ Install the Authorized Modification label on replacement PCM (label packaged with PCM). Enter the date of the PCM replacement, Dealer Code and new Catch Word found on replacement PCM label.
^ For PATS equipped vehicles, refer to Workshop Manual (section 09-40 POWERTRAIN CONTROL MODULE INITIALIZATION). Be sure to verify that all of the customer's keys start the vehicle.
5. Test drive vehicle to determine if knock or ping noise has been eliminated.
^ If condition is eliminated, return vehicle to customer.
^ If condition is still present, proceed to "Octane Adjustment And Timing Retard Procedure."
NOTE:
Engine knock will be significantly reduced after PCM replacement. Do not be concerned if the engine exhibits slight knock or ping under certain driving conditions after PCM replacement. This is considered a normal characteristic for this particular application.
OCTANE ADJUSTMENT AND TIMING RETARD PROCEDURE
^ Only perform the following steps if PCM replacement did not repair vehicle.
^ Engine performance may be slightly reduced. Octane adjust and timing retard can be performed a maximum of two(2) times without reflashing the PCM. If this procedure must performed more than two(2) times, PCM reflashing will be necessary due to design intent.
1. Using NGS Diagnostic Card V9.0 (P/N 49T0-88-010K), with NGS in-car flashing cable (P/N 49G0-88-O0110) and ignition in the ON position, enter the vehicle parameters by selecting VEHICLE & ENGINE SELECTION."
2. Select "Diagnostic Data Link."
3. Select "PCM."
4. Select "Model Configuration."
5. Turn key to OFF position then return to ON position (menu will reappear on NGS Tester).
6. Check octane adjust status:
^ If current status is "NO RETARD", proceed to STEP 7.
^ If current status is "RETARD", proceed to STEP 8.
7. Change setting to "RETARD" in the update column.
NOTE:
Do not change fuel octane or fuel type with the NGS Diagnostic Card V9.0. Only octane adjust (no retard/retard) should be used to modify for knock prevention.
8. Verify repair.
PART(S) INFORMATION
PCM Reference Chart
Locate "Catch Word" on vehicle firewall adjacent to PCM, or on the white tag on original PCM. Use the chart below to determine the correct PCM.
WARRANTY INFORMATION
NOTE:
This information applies to verified customer complaints on vehicles covered under normal warranty. Refer to the SRT microfiche for warranty term information.