Powertrain/Exhaust - Rough Idle/Boom/Vibration
Engine01-026/04
2001-2004 B-SERIES TRUCKS - B2300 - ROUGH
IDLE AND/OR 1800-2200 RPM BOOM/VIBRATION
APPLICABLE MODEL(S)/VINS
2001-2004 B-Series Trucks - B2300 Regular Cab
DESCRIPTION
On some 2001-2004 B2300 trucks, customers may complain of one or both of the following:
^ Boom or vibration between 1,800-2,200 RPM caused by exhaust system tuning and the powertrain and exhaust not being neutralized.
^ Rough idle caused by the powertrain and exhaust system not being neutralized.
Customers having this concern should have their vehicle repaired using the following repair procedure.
NOTE:
4-cylinder engines will have a nominal level of powertrain boom, vibration or rough idle. It is recommended to compare the customer vehicle to a similar B2300 to determine if the level of boom, vibration or rough idle is abnormal before proceeding with any repairs.
REPAIR PROCEDURE
NEUTRALIZING POWERTRAIN & EXHAUST SYSTEM - AUTOMATIC TRANSMISSION MODELS
NOTE:
For 2003 B2300 vehicles equipped with A/T with ROUGH IDLE only symptom, reprogram the PCM. See PCM REPROGRAMMING - 2003 AUTOMATIC TRANSMISSION MODELS ONLY. For 2003 B2300 vehicles equipped with A/T and all other A/T equipped vehicles with BOOM/VIBRATION symptom, perform the following procedure.
1. Verify customer concern.
2. Loosen but do not remove the following:
^ Left engine support insulator nuts.
^ Right engine support insulator nuts.
^ Transmission extension housing to cross member mount nuts.
^ Exhaust manifold to catalytic converter pipe nuts.
3. Muffler and exhaust pipe repair:
^ For 2001-2003 models with an 1,800-2,200 RPM boom/vibration:
Install the new muffler and exhaust pipe assembly and new front and rear hangers. Refer to 01-15A - EXHAUST SYSTEM 2.3L for removal and installation procedures. Leave the catalytic converter pipe to muffler and exhaust pipe connection loose after installation. Torque the front and rear hanger nuts to 23 N.m (17 lb-ft) and go to STEP 4.
^ For 2004 models with an 1,800-2,200 RPM boom/vibration and for 2001, 2002 and 2004 models with a rough idle:
^ Do not change the muffler and exhaust pipe. Loosen the nuts at the flange between the catalytic converter pipe and exhaust pipe and go to STEP 4.
4. Use the following procedure to neutralize the powertrain and exhaust system:
a. Start the engine.
b. Apply the park brake and the service brake.
c. Place the transmission in Drive.
d. Slightly raise engine RPM to torque Powertrain.
e. Place the transmission in Reverse.
f. Slightly raise engine RPM to torque Powertrain.
g. Repeat this process again.
h. Place transmission in Park and turn off engine.
5. Torque the powertrain and exhaust system attachments to specification in the following sequence:
a. Left engine insulator nuts - Tightening Torque: 102 N.m (75 lb-ft).
b. Right engine insulator nuts - Tightening Torque: 102 N.m (75 lb-ft).
c. Transmission extension housing-to-cross member mount nuts - Tightening Torque: 99 N.m (73 lb-ft).
d. Exhaust manifold-to-catalytic converter pipe nuts (support the catalytic converter and pipe in a neutral position while tightening) - Tightening Torque: 40 N.m (30 lb-ft).
e. Catalytic converter pipe-to-muffler and exhaust pipe nuts (do not support the exhaust system while tightening) - Tightening Torque: 40 N.m (30 lb-ft).
6. Check the Powertrain and exhaust to ensure there are no points grounded out to the body. Inspect for other possible ground-outs to the dash-panel, like wire harness, hoses, etc.
NOTE:
Only automatic transmission models have an exhaust damper installed. Positioning of this damper is important and is explained in STEP 7.
7. Check for the proper installation of the exhaust damper in front of the catalytic converter to muffler and exhaust pipe connection. The damper should be located 114 mm (4.5") forward of the catalytic converter flange and at an angle of 54 degrees from horizontal. Torque the exhaust damper attaching nuts - Tightening Torque: 47.5 N.m (35 lb-ft).
8. Start the engine and check for exhaust system leaks.
9. Verify repair.
NEUTRALIZING POWERTRAIN & EXHAUST SYSTEM - MANUAL TRANSMISSION MODELS
1. Verify customer concern.
2. Loosen but do not remove the following:
^ Left engine support insulator nuts.
^ Right engine support insulator nuts.
^ Transmission extension housing to cross member mount nuts.
Exhaust manifold to catalytic converter pipe nuts.
3. Muffler and exhaust pipe repair:
^ For 2001-2003 models with an 1800-2200 RPM boom/vibration:
^ Install the new muffler and exhaust pipe assembly and new front and rear hangers. Refer to 01-15A - EXHAUST SYSTEM 2.3L for removal and installation procedures. Leave the catalytic converter pipe to muffler and exhaust pipe connection loose after installation. Torque the front and rear hanger nuts to 23 N.m (17 lb-ft) and go to STEP 4.
^ For 2004 models with an 1800-2200 RPM boom/vibration and for 2001-2004 models with a rough idle:
^ Do not change the muffler and exhaust pipe. Loosen the nuts at the flange between the catalytic converter pipe and muffler and exhaust pipe and go to STEP 4.
4. Use the following procedure to neutralize the powertrain and exhaust system:
a. Start the engine.
b. Apply the park brake.
c. Place the transmission in 1st gear.
d. Slightly raise engine RPM and slowly let out clutch until Powertrain moves/shifts under torque.
e. Place the transmission in reverse.
f. Slightly raise engine RPM and slowly let out clutch until Powertrain moves/shifts under torque.
g. Repeat this process again.
h. Place transmission in Neutral and turn off engine.
5. Torque the powertrain and exhaust system attachments to specification in the following sequence:
a. Left engine insulator nuts - Tightening Torque: 102 N.m (75 lb-ft).
b. Right engine insulator nuts - Tightening Torque: 102 N.m (75 lb-ft).
c. Transmission extension housing-to-cross member mount nuts - Tightening Torque: 98 N.m (72 lb-ft).
d. Exhaust manifold to catalytic converter pipe nuts (support the catalytic conveter and pipe in a neutral position while tightening) - Tightening Torque: 40 N.m (30 lb-ft).
e. Catalytic converter pipe-to-muffler and exhaust pipe nuts (do not support the exhaust pipe while tightening) - Tightening Torque: 40 N.m (30 lb-ft).
NOTE:
Manual transmission models do not require an exhaust damper.
6. Check the powertrain and exhaust to ensure there are no points grounded out to the body. Inspect for other possible ground-outs to the dash-panel, like wire harness, hoses, etc.
7. Start the engine and check for exhaust system leaks.
8. Verify repair.
PCM REPROGRAMMING - 2003 AUTOMATIC TRANSMISSION MODELS ONLY
1. Using WDS B25.6 or later software, reprogram the PCM to the latest calibration (refer to "Calibration Information" table) by following the "Module Reprogramming" procedure.
NOTE:
^ Always update the WDS PTU first, then install the needed calibration file that WDS shows during PCM reprogramming. Go to "WDS Calibration" on ESI and download the "update" file. If the PTU is not updated to the latest WDS calibration level, the calibration file will not install into the PTU.
^ WDS shows the calibration part numbers afler programming the PCM.
^ Please be aware that PCM calibration part numbers and file names listed in any Service Bulletin may change due to future releases of WDS software, and additional revisions made to those calibrations for service related concerns.
^ When reprogramming a PCM, WDS will always display the "latest" calibration P/N available for that vehicle. If any calibration has been revised/updated to contain new information for a new service concern/issue, it will also contain all previously released calibrations.
^ When performing this procedure, if the WDS PTU is not docked and connected to 115V-120V, we recommend that a battery charger be installed on the vehicle battery and turned ON to a maximum charge of no more than 20 AMPS to keep the vehicle battery up to capacity. If you exceed 20 AMPS, it will damage the WDS PTU.
^ Install an "Authorized Modification" label (P/N 9999-95-AMDC-97) with the new calibration information next to the Emission Control sticker on the radiator support. The "Authorized Modification" label will inform technicians of the PCM calibration change if future repairs are necessary.
2. Afier performing the PCM reprogramming procedure, verify the repair by starting the engine and making sure there are no MIL illumination or abnormal warning lights present.
NOTE:
After PCM reprogramming, it is no longer necessary to road test the vehicle to "relearn" KAM (Keep Alive Memory).
CALIBRATION INFORMATION
NOTE:
The PCM Calibration Part Numbers listed above are provided for PCM reprogramming purposes only. These are not necessarily the same Mazda part numbers used to order an actual PCM through the Mazda Parts System. It is not necessary to order a PCM as part of this repair procedure.
PART(S) INFORMATION
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.