For 1990-2009 cars

# DIESEL INOP METERING VALVE SENSOR INFORMATION

THE 1984 "A" WITH V-6 DIESEL ENGINES THAT ARE SOLD IN CALIFORNIA AND THE 1985 FRONT-WHEEL-DRIVE "C" SOLD IN ALL STATES WILL CONTAIN A METERING VALVE SENSOR (MVS). A RUST PREVENTATIVE IN THE CURRENT TEST FLUID USED IN CALIBRATION STANDS AT THE ROOSA MASTER DEALER WILL COAT THE MVS AND RENDER IT INOPERATIVE. A NEW TEST FLUID IS IN THE PROCESS OF BEING INTRODUCED. THIS NEW FLUID HAS NO EFFECT ON THE MVS. UNTIL SUCH TIME AS THE NEW TEST FLUID IS IN THE CALIBRATION STANDS, IT WILL BE NECESSARY TO FLUSH THE MVS WITH DIESEL FUEL AFTER THE PUMP HAS BEEN INSTALLED ON THE CAR. THE PROCEDURE TO FLUSH THE PUMP FOLLOWS. THE ROOSA MASTER DEALER CANNOT ADJUST THE MVS IF REQUIRED UNTIL THE NEW TEST FLUID IS AVAILABLE. BECAUSE OF THIS, IT MAY ALSO BE NECESSARY TO FLUSH AND ADJUST THE MVS. THE MVS ADJUSTING PROCEDURE IS CONTAINED IN THE SERVICE MANUAL. THE ROOSA MASTER DEALER WILL ATTACH A TAG TO THOSE PUMPS THAT WILL REQUIRE FLUSHING AND ADJUSTING AS FOLLOWS: STANADYNE NO. COLOR OPERATION 99195 YELLOW FLUSH ONLY 99196 RED FLUSH AND ADJUST PERFORM THE OPERATIONS REQUIRED PER THE TAG. STAPLE THE TAG TO THE SCRAPPING COPY OF THE REPAIR ORDER AS YOUR AUTHORIZATION TO PERFORM THE OPERATION. FLUSHING THE METERING VALVE SENSOR (MVS) - WITH THE AIR CROSSOVER REMOVED 1. PLACE A SHOP TOWEL UNDER THE INJECTION PUMP. 2. DISCONNECT THE HPCA/FAST IDLE SWITCH LEAD AT THE CYLINDER HEAD BOLT TEMPERATURE SWITCH. 3. HOLD THE MVS AND REMOVE THE MVS ADJUSTING HOLE PLUG. 4. ASSEMBLE ONTO A J-28526 ADAPTER (1978-79 HOUSING PRESSURE), A 561888 SEAL AND WASHER OR EQUIVALENT (ITEM 2) AND FLAT WASHER. USE ENOUGH FLAT WASHERS (ITEM 3) SO THAT THE DISTANCE FROM THE SEAL TO THE END OF THE ADAPTER IS 3 MM (3/32"). SEE ITEM 1 IN ILLUSTRATION 5. INSTALL A HOSE FITTING INTO THE J-28526 ADAPTER SHOWN AS ITEM 5 IN THE ILLUSTRATION. 6. INSTALL THE J-28526 ADAPTER WITH WASHERS AND FITTING INTO THE MVS ADJUSTING HOLE. HOLD THE MVS ASSEMBLY AND TORQUE THE J-28526 TO 3.5 N.M (30 LBS. IN.). 7. PLACE A 4 LITER (ONE GALLON) FUEL RESISTANT CONTAINER CLOSE TO THE CAR. 8. INSTALL A LENGTH OF FUEL RESISTANT HOSE ON THE FITTING AND PLACE THE OPEN END OF THE HOSE INTO THE FUEL RESISTANT CONTAINER. 9. START THE ENGINE AND CORRECT ANY FUEL LEAKS. RUN THE ENGINE FOUR (4) MINUTES. 10. SHUT OFF THE ENGINE. DISCONNECT THE HOSE FROM THE FITTING, AND DRAIN AND REMOVE THE HOSE FROM THE CONTAINER. 11. DISPOSE OF THE FUEL IN A SUITABLE MANNER. IT CAN BE REUSED IN THE FUEL TANK IF IT IS CLEAN. 12. REMOVE THE J-28526 ADAPTER. WHILE HOLDING THE MVS ASSEMBLY, INSTALL THE MVS ADJUSTING HOLE PLUG, (USING A NEW "O" RING IF REQUIRED), AND TIGHTEN IT TO 3.5 NM (30 LBS. IN.). 13. REMOVE THE SHOP TOWEL AND CLEAN ANY SPILLED FLUID. 14. START THE ENGINE AND CHECK FOR LEAKS. 15. RECONNECT THE HPCA CONNECTOR.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.