Contents Wiring diagrams Section: Testing & Diagnostics All sections

Engine Controls - Tests W/o Codes: NVH Chevrolet Sportvan G20

ENGINE STARTS, IDLES ROUGH W/O UNUSUAL NOISE OR SMOKE TABLE

Possible CauseCorrection
Incorrect slow idle adjustmentReset slow idle adjustment, see ADJUSTMENTS
Leaking injection lineCheck fittings and/or replace line
Plugged fuel return lineRemove restrictions
Air in lines to nozzlesCheck line fittings
Air in injection pumpCheck pump fittings and pump operation
Faulty nozzleReplace nozzle, see SYSTEM/COMP TESTS
Improper or contaminated fuelRemove and replace fuel
Uneven fuel distributionCheck fuel delivery system

ENGINE STARTS, IDLES ROUGH W/O UNUSUAL NOISE OR SMOKE

ENGINE STARTS & IDLES W/EXCESSIVE NOISE AND/OR SMOKE TABLE

Possible CauseCorrection
Incorrect pump timingAdjust pump timing, see ADJUSTMENTS
Restricted Air FilterCheck and/or replace air filter
Air in injection lines to nozzlesCheck fittings on lines
Faulty nozzleReplace nozzle, see SYSTEM/COMP TESTS
Improperly installed high pressure linesRemove and reinstall properly

ENGINE STARTS AND IDLES W/EXCESSIVE NOISE AND/OR SMOKE

"RAPPING" NOISE FROM CYLINDERS

Possible CauseCorrection
Air in fuel systemCheck fuel delivery system for leaks
Air in high pressure linesCheck fittings for leaks
Nozzle sticking in open positionInspect nozzle and/or replace
Low nozzle opening pressureCheck nozzle operation, see SYSTEM/COMP TESTS

"RAPPING" NOISE FROM CYLINDERS

EXCESSIVE NOISE WITH BLACK SMOKE

Possible CauseCorrection
Incorrect pump timingAdjust pump timing, see ADJUSTMENTS
Incorrect pump housing pressureCheck pump for internal leaks
Defective injection pumpReplace injection pump, see SYSTEM/COMP TESTS

EXCESSIVE NOISE WITH BLACK SMOKE