TECH TIPS FOR JULY, 1994

1992 FORD CROWN VICTORIA, AND LINCOLN MERCURY GRAND MARQUES ARE SUSCEPTIBLE TO ALTERNATOR "WHINE" DURING THE AM/FM/TAPE PLAYING MODE. THIS IS USUALLY MOST NOTICEABLE IN THE CASSETTE TAPE MODE. THE PROBLEM OCCURS BECAUSE NOISE SUPPRESSION COMPONENTS WERE NOT INCORPORATED INTO THE PREMIUM SOUND SYSTEM. IF YOU DETERMINE THAT THERE IS REALLY ALTERNATOR "WHINE" IN THE SOUND SYSTEM, INSTALL AN 'AUDIO SERVICE KIT' (PART # F2AZ18887A).
SOURCE FORD TECHNICAL BULLETINS.

A VOLKSWAGEN TECHNICAL BULLETIN DATED NOVEMBER, 1993 INDICATES THAT 1985 & ON VANAGON & GOLF/JETTA/CABRIOLET AS WELL AS FOX FROM 1991 ON CAN EXHIBIT WHAT WOULD BE A REALLY FRUSTRATING, INTERMITTENT PROBLEM.  AFTER RUNNING AT A CONSTANT SPEED FOR 1/2 TO 2 HOURS THE CAR WILL LOSE POWER, CUT OUT, OR STALL OFTEN ACCOMPANIED BY BUCKING OR JERKING.

IN ALL CASES THE CAR WILL IMMEDIATELY RESTART, AND THE PROBLEM MIGHT NOT OCCUR AGAIN FOR DAYS, WEEKS OR EVEN MONTHS. NORMAL SERVICE PROCEDURES WILL SHOW NOTHING AND THE FIRST TIME IT IS LIKELY TO BE BLAMED ON "BAD GAS" OR DIRT IN THE LINE. SOME "MASS AIR FLOW SENSORS" CAN HAVE A VIBRATION RESONANCE OF THE METERING POTENTIOMETER WIPER, DURING AN EXTENDED DRIVE AT A CONSTANT SPEED. THIS RESONANCE CAUSES THE "MASS AIR FLOW SENSOR" TO SUPPLY AN INTERMITTENT SIGNAL TO THE ECM. THE ECM WILL THEN DEFAULT TO A "NO LOAD" CONDITION AND REDUCE THE INJECTION TIME.
(AND NO, I DIDN'T MAKE THIS UP!)

THE BULLETIN REPORTS THAT PART # 025 906 302 A, IS AVAILABLE TO RESOLVE THE PROBLEM, BUT WARNS THAT THE # IS FOR REFERENCE PURPOSES AND YOU SHOULD CHECK WITH THE PARTS DEPARTMENT AT THE LOCAL DEALERSHIP FOR THE CORRECT, UP TO DATE PART.

BMW SERVICE BULLETIN (DECEMBER 1993) INDICATES A PROBLEM WITH POTENTIALLY ALL MODELS, RELATED TO THEIR CHARGING SYSTEMS. THE SYMPTOMS ARE AN EXCESSIVELY HIGH CHARGE RATE OR SEVERELY FLUCTUATING VOLTAGE. OWNERS HAVE REPORTED THE "CHECK ENGINE" & "TRANS PROGRAM" LIGHT COMING ON, ALONG WITH FLUCTUATIONS IN THE INTENSITY OF THE HEADLIGHTS A INSTRUMENT CLUSTER LIGHTS. THE DME CONTROL WILL SHOW A CODE 54(VOLTAGE TOO HIGH), AND THE EGS CONTROL MODULE SET A CODE 37(BATTERY SUPPLY VOLTAGE) INTO THEIR MEMORIES. IT IS THESE CODES WHICH CAUSE THE "CHECK ENGINE" & "TRANS PROGRAM" WARNINGS.

THE CAUSE OF THIS IS THE VOLTAGE REGULATOR HAS FAILED. WHENEVER A VEHICLE WITH SUCH A COMPLAINT IS ENCOUNTERED THE CHARGING SYSTEM SHOULD BE THOROUGHLY CHECKED. A PROPERLY WORKING SYSTEM, WITH A GOOD,FULLY CHARGED BATTERY & NO LOADS TURNED ON, WITH THE ENGINE AT 1500 RPM; SHOULD A VOLTAGE OUTPUT OF BETWEEN 13.5 - 14.4 VOLTS. A READING HIGHER OR LOWER INDICATES A PROBLEM WHICH WILL REQUIRE FIXING. THE BULLETIN CLOSES BY SAYING THAT A DEFECTIVE VOLTAGE REGULATOR SHOULD BE REPLACED. (BETCHA NEVER WOULD HAVE THOUGHT OF THAT).

FORD HAS ISSUED A BULLETIN, INDICATING A PROBLEM WITH 1992-93 EXPLORERS, WHERE BATTERY ACID EMISSIONS CAUSED BY GASSING CAN CAUSE NEARBY WIRING TO CORRODE, AND/OR SWELL UP TO THE POINT THAT THERE CAN BE A NO START CONDITION. THERE IS A FAIRLY EXTENSIVE REPAIR/PART PROCEDURE TO CORRECT THIS CONDITION SHOULD YOU RUN ACROSS IT.

CONNECTING TRAILER LIGHTS DIRECTLY INTO THE VEHICLE WIRING HARNESS AT THE REAR OF THE VEHICLE CAN DAMAGE THE LAMP OUTAGE MODULE ON 1993/1994 (ZJ) GRAND CHEROKEE & GRAND WAGONEER MODELS. THE LAMP OUTAGE MODULE IS RATED FOR 5 AMPS AND WITH THE ADDITION OF TRAILER LIGHTING THIS CAN BE EXCEEDED. IF TRAILER TOWING IS DESIRABLE AND THE VEHICLE DOES NOT HAVE A FACTORY TOWING PACKAGE, THE ACCESSORY PACKAGE IS THE ONLY APPROVE ONE WHICH WILL BYPASS THE LAMP OUTAGE MODULE. SOURCE: CHRYSLER TECHNICAL SERVICE BULLETINS, JANUARY 1994.