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TSB 11-05-96

Diesel Turbocharger Diagnostic Procedure

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Date: Aug. 23,1996

Models: 1994 - 1997 (BR) Ram Truck

NOTE: THIS BULLETIN APPLIES TO VEHICLES EQUIPPED WITH THE 5.9L CUMMINS DIESEL ENGINE.

Symptoms:

The following conditions may be related to the turbocharger:  

Diagnosis:

Proper turbocharger diagnosis is critical for customer satisfaction. Noise that sounds like a malfunctioning turbocharger may not be coming from the turbocharger. Low power complaints could be due to fuel injection malfunctions. Therefore, it is essential that the following diagnosis be performed prior to any turbocharger replacement.

Diesel Turbocharger Diagnosis
Step
Action
Yes
No
NOTE: PRIOR TO PERFORMING ANY DIESEL TURBOCHARGER NOISE DIAGNOSIS, GET A DETAILED DESCRIPTION OF ANY TURBOCHARGER NOISE AND IF POSSIBLE, TEST DRIVE THE VEHICLE WITH THE CUSTOMER AND LET THE CUSTOMER IDENTIFY THE NOISE AS IT OCCURS
1

Drive the vehicle using a variety of engine loads and speeds.

  • Does the turbocharger emit a noise that Increases and decreases with engine load and speed and is not considered NORMAL?
Proceed to STEP 2. Proceed to STEP 4.
2

With the engine at idle, transmission in park/neutral, and the parking brake set, check for escaping air/boost at each hose connection between the turbocharger compressor outlet and the intake manifold by applying a soap and water solution at each connection and watch for bubbles forming.

  • Are there leaks at the hose connections?
Tighten or replace the appropriate hose clamp at the connection determined to be leaking. Perform the task once again to verify that the leak has been repaired. Proceed to STEP 3.
3

Inspect for exhaust leaks at all joints/connections from the exhaust manifold back to the tail pipe. WARNING: THE EXHAUST SYSTEM MAY BE EXTREMELY HOT. USE EXTREME CAUTION WHILE INSPECTING FOR EXHAUST LEAKS.

  • Are there exhaust leaks?
Repair as necessary. Proceed to STEP 4.
4
  • Does the turbocharger emit a noise that occurs over a narrow speed range and sound like the exhaust is howling during boost conditions?
Proceed to STEP 5. Proceed to STEP 6.
5

Wedge a small 2X4 between the frame rail and the flat area in the middle of the muffler. Repeat the driving condition in which the howing occurred.

  • Does the noise re-occur?
Remove 2X4 and proceed to STEP 6. This condition is caused by a muffler tunning issue. Replacing the turbocharger vvill not correct this condition. NOTE: REMOVE 2X4 BEFORE RETURNING THE VEHICLE TO THE CUSTOMER.
6
  • Does the turbocharger emit a noise that is a loud popping/whooshing/ flushing/fluttering noise during closed throttle deceleration?

NOTE: THIS NOISE SEEMS TO BE COMING FROM THE AIR CLEANER

This condition is normal and harmless. It is caused by the inability of the engine to intake higher boost levels present at the beginning of a sudden closed throttle deceleration. DO NOT REPLACE THE TURBOCHARGER FOR THIS CONDITION Proceed to STEP 7.
7

With the engine OFF, remove the air cleaner to turbocharger tube. Inspect the compressor wheel for proper free play. While pushing the shaft left, right, up, down, gently rotate the compressor wheel. The compressor wheel should spin freely by hand.

NOTE: A SMALL AMOUNT OF END PLAY IS NORMAL HOWEVER, BLADES SHOULD NOT TOUCH THE HOUSING.

  • Does the compressor wheel have excessive end play or does the compressor wheel contact the housing?
Replace the turbocharger. Turbocharger replacement Wll not correct the noise condition.

 Lack of Acceleration from Low Boost Diagnosis
Step
Action
Yes
No
1

Drive the vehicle using a variety of engine loads and speeds.

  • Is there a lack of acceleration?
Proceed to STEP 2 The condition cannot be verifled at this time.
2

With the engine OFF, remove the air cleaner to turbocharger tube. Inspect the compressor wheel for proper free play. While pushing the shaft left, right, up, down, gently rotate the compressor wheel. The compressor wheel should spin freely by hand.

NOTE: A SMALL AMOUNT OF END PLAY IS NORMAL HOWEVER, BLADES SHOULD NOT TOUCH THE HOUSING.

  • Does the compressor wheel have excessive end play or does the compressor wheel contact the housing?
Replace the turbocharger. Proceed to STEP 3
3 Use the procedure outlined in Technical Service Bulletin 18-29-95 Rev. A, Dated October 16, 1995 for diesel low power/performance diagnosis. If the turbocharger is suspect for a "lack of acceleration" complaint, refer to the 1996 Ram Truck Servlce Manual (publication No. 81-370-6108). page 11 -19 and 11 -20, for proper wastegate adjustment procedures.

Diesel Turbocharger Oil Leak Diagnosis
Step
Action
Yes
No
1

Does there appear to be oil leaking from the turbocharger shaft seal with wet oil present in the compressor cover?

NOTE: A VERY SMALL LIGHT MISTIFILM OF OIL IS NORMAL AND IS NOT CONSIDERED A MALFUNCTION

Proceed to STEP 2. Turbocharger replacement Wll not correct the oil leakage condition.
2

Inspect air cleaner inlet system for any restrictions (dirty air cleaner, collapsed inlet duct, foreign object, etc.). A restriction before the compressor inlet can create a vaculim and draw oil from the turbocharger.

  • Are there any resthetions?
Repair as necessary. Proceed to STEP 3.
3

Inspect the engine for signs of excessive engine blow- by (excessive oil drainage fro the draft tube or draft tube kinked/obstructed). An obstruction will Increase crankcase pressure, forcing oil back up through the turbo drain.

  • Is the draft tube kinked/lobstructed or is there any signs of excessive engine blow-by?
Repair as necessary, Proceed to STEP 4.
4
  • Is the turbocharger oil drain functioning property, or is it kinked/damagedlobstructed?
Repair as necessary. Replace the turbocharger

notes:

POLICY - Information Only


Thanks to Bob Bergevin and Barry Drodge for supplying this TSB information

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This page was edited on: May 3, 2004