NHTSA Engineering Analysis EA04022: ENGINE STALLING
ODI OPENED THE INVESTIGATION TO EXAMINE STALLING ALLEGATIONS ON 1998-2002 CUMMINS 5.9 LITER DIESEL ENGINES.DURING THE INVESTIGATION ODI FOUND THAT THE ENGINE IS USED IN SCHOOL AND TRANSIT BUSES, EMERGENCY VEHICLES, MEDIUM DUTY TRUCKS, LIGHT TRUCKS, RV'S, AND CARGO VANS.ODI CONTACTED CUMMINS AND CHRYSLER (LARGEST VEHICLE MANUFACTURER), VISITED SCHOOL BUS FLEETS, CONDUCTED INTERVIEWS AND CONDUCTED TESTING OF LIGHT VEHICLES TO QUANTIFY THE FAILURE MODE. ODI OBSERVED THAT THE LIFT PUMP, A PART OF THE FUEL SYSTEM, FAILS, RESULTING IN REDUCED FLOW TO THE INJECTOR PUMP.WHEN THIS PROBLEM OCCURS, THE ENGINE EXPERIENCES SEVERE DRIVABILITY ISSUES, SUCH AS LOW SPEED, LOW POWER, SMOKING AND POOR ACCELERATION.HEAVIER VEHICLES SUCH AS SCHOOL BUSES WITH A GVWR OF 33,000 POUNDS MAY EXPERIENCE A STALL.ODI VERIFIED VIA INTERVIEWS THAT SOME SCHOOL BUSES ACTUALLY STALLED RESULTING IN THE TRANSFER OF STUDENTS ON THE ROADSIDE.ODI'S TESTING SHOWED THAT LIGHT VEHICLES WOULD SUFFER THE SEVERE DRIVABILITY ISSUES AND THEN GRADUALLY RECOVER.A LIGHT VEHICLE WAS DRIVEN AT LOW AND HIGH SPEEDS FOR AN HOUR WITHOUT A TRUE ENGINE STALL OCCURRING.ODI'S TECHNICAL REPORT, WHICH CONTAINS FULL DETAILS, AND A COPY OF THE CUMMINS RECALL ARE ATTACHED.
US National Highway Traffic Safety Administration