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For 1990-2009 cars only

6.6L LB7 No start , Loss of Power , White Smoke - cold diesel fluid fuel hard leak no performance poor power

Subject:6.6L LB7 No Start, Loss of Power, White Smoke

Models:.



When servicing the vehicle with the VIN you entered, the following diagnosis might be helpful if the vehicle exhibits the described symptoms.

Condition/Concern:

01 02 03 C/K 6.6L LB7 no start, loss of power, white smoke

Recommendation/Instructions:

Use J-44638 - Fuel Pressure gage to:

  1. Check suction capability of injection pump - reference SI Document number 742189.
  2. Verify fuel filter is capable of priming fuel system to 10 MPSI - Reference SI Document number 745386 - step 13.
  3. Items to check causing a for restriction indicated by high vacuum readings:
  4. A. Plugged fuel filter.

    B. Pinched or collapsed suction hose between injection pump and tank.

  5. Items to check for low vacuum on suction side of fuel system:
  6. A. Leak at quick connect fittings

    B. Loose clamped hose connections

    C. Fuel filter connections

    D. Fuel filter bleed screw not secure

Common gage readings:

Engine Speed

Gage

 

Idle

1"- 3" Hg VAC

normal

3000 RPM no load

3"- 5"Hg VAC

normal at operating temp

Hard accelerations

6"-10" Hg VAC

normal

With the engine off and priming the fuel system by pumping the hand primer on the fuel filter, you should be able to get 10 PSI on the gage. This pressure will slowly drop to zero. A normal bleed down time is 2 minutes. If pressure drops quickly after priming the system, suspect a leak between the fuel filter and the injection pump.

Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance. This diagnostic approach was developed for the vehicle with the VIN you entered and should not be automatically be used for other vehicles with similar symptoms.

Models:

(01, 02, 03 Chevrolet Silverado/GMC Sierra 2500 HD)and (01, 02, 03 Chevrolet Silverado/GMC Sierra 3500)