TECH TIP FOR APRIL, 1994

CHRYSLER MOTOR CORPORATION ADVISES THAT THE BROWN STAINING FOUND ON SPARK PLUGS ABOVE THE METAL SHELL AND BELOW THE PLUG BOOT IS NORMAL AND DOES NOT INDICATE A DEFECTIVE PLUG OR OTHER PROBLEM.APPARENTLY THE IGNITION SYSTEM GENERATES A CORONA IN THE AREA NOT COVER BY THE BOOT. THE ELECTRICAL CAPACITANCE OF THE SPARK PLUG CREATES AN ELECTRICAL FIELD IN THE AREA OF THE PLUG, AND THIS FIELD GENERATES OZONE WHICH IS A VERY ACTIVE FORM OF OXYGEN.

THE OZONE WILL COMBINE WITH ANY CONTAMINANT NEAR THE PLUG TO FORM THIS HARMLESS BROWN STAIN. THIS IS APPARENTLY PREVALENT ON THE 3.5L ENGINES.

BEFORE YOU INSTALL AN A/C SWITCH BACK INTO A '92-93 HONDA CIVIC, HAVE ANOTHER LOOK AT THE SWITCH CAP YOU REMOVED. IF THE CAP'S LOCKING TAB IS BROKEN OFF, DON'T INSTALL THE BUTTON UNTIL YOU RETRIEVE THE MISSING TAB FROM INSIDE THE HOLE. OTHERWISE THERE IS A GOOD CHANCE THAT YOU WILL RUIN BOTH THE PANEL AND THE BUTTON.

ON ALL G.M. VEHICLES EQUIPPED WITH AIR BAGS, IT IS APPARENTLY ABSOLUTELY IMPERATIVE THAT YOUR DISCONNECT THE NEGATIVE BATTERY TERMINAL FIRST, IF FOR ANY REASON YOU ARE COMPLETELY SHUTTING THE POWER OFF. IF YOU DON'T, YOU STAND A GOOD CHANCE OF DEPLOYING THE AIR BAGS, AND SINCE THE REMOVAL OF A BATTERY IS USUALLY LEFT TO THE LEAST EXPERIENCED EMPLOYEE, THE POSSIBILITY OF RUNNING UP A HUGE BILL IS A REAL DANGER.

ON THE SAME THEME, THE USE OF THE 9VT BATTERIES WHICH PLUG INTO THE CIGARETTE LIGHTER IS BECOMING A VERY QUESTIONABLE PRACTICE. SOME SYSTEMS WILL SENSE THIS AS A REASON TO DEPLOY THE AIR BAGS, AND SOME OF THE STEREO SYSTEMS WITH BUILT IN SECURITY, WILL THINK YOU ARE TRYING TO STEAL THE RADIO, AND WILL WIPE OUT ALL THE OPERATING CODES.

IN ADDITION THE LIGHTERS IN SOME NEWER CARS ARE NOT ON FULL TIME, BUT RATHER ONLY WHEN THE KEY IS ON. YOU MUST CHECK BEFORE PLUGGING IN EVEN A 12VTS SOURSE, BECAUSE IF ITS NOT LIVE WITH THE KEY OFF, YOU ARE GOING TO HAVE A PROBLEM.

ON 1988-93 C/K SERIES GMC TRUCKS, THERE IS A DANGER OF TRAPPING THE INJECTOR WIRES BETWEEN THE AIR CLEANER AND EXTENSION RING, OR BETWEEN THE EXTENSION RING AND THE THROTTLE BODY. TO REDUCE THE POSSIBILITY OF THIS OCCURRENCE, THE INJECTOR WIRES SHOULD BE REMOVED AND TWISTED "ONCE" ONLY TO REMOVE SOME OF THE SLACK.

IF A CUSTOMER COMPLAINS OF PERSISTENT RADIO INTERFERENCE AND YOU HAVE RUN OUT OF POSSIBLE SOLUTIONS, REPLACE THE GROUND CABLE FROM THE BATTERY TO THE ENGINE/CHASSIS WITH ONE OF THE BRAIDED TYPES. IT SEEMS THAT AS THE WIRES CROSS ONE ANOTHER MOST OF THE INTERFERENCE WILL BE CANCELLED OUT.

MOST OF THE ABOVE TECH INFORMATION WAS RECEIVED FROM " THE ELECTRICAL CONNECTION" AN A.P.R.A. PUBLICATION. THIS ORGANISATION HAS ACCESS TO MANY MANUFACTURER'S SERVICE MANUALS.

LATER MODEL FORD PRODUCTS (USUALLY TEMPO/TAURUS), USE 2 DIFFERENT ALTERNATORS WHICH CAN EXHIBIT DIFFERENT CHARGING PROBLEMS. ON THE FORD BUILT INTERNALLY REGULATED (REGULATOR IS ATTACHED TO THE BACK OF THE ALTERNATOR), IF THE UNIT APPEARS TO CHARGE PROPERLY BUT THE LIGHT IS ON, THERE IS A BREAK IN THE CONNECTION BETWEEN THE "S" TERMINAL IN THE REGULATOR PLUG (THE SMALLER PLUG)AND THE SAME TERMINAL IN THE MAIN BATTERY PLUG. REMEMBER WHEN REMOVING THE BATTERY PLUG FOR TESTING, DO NOT WIGGLE IT OUT AND REPLACE THE CONTACT GEL WHEN REINSTALLING. THE CONTACT GEL IS NOT DIELECTRIC GREASE BUT A SPECIAL COMPOUND.

WITH THE MITSUBISHI ALTERNATOR, IF THE UNIT IS CHARGING BUT IS OVERCHARGING (15+ VTS), THE PROBLEM CAN SOMETIMES BE TRACED TO AN OPEN FUSIBLE LINK IN THE WIRE LEADING TO THE "A" TERMINAL IN THE REGULATOR PLUG.

FROM B&B AUTO ELECTRIC, WOODSTOCK: ON AT LEAST 1984 VW DIESELS BUT PROBABLY ON OTHER YEARS AS WELL, THE ON/OFF FOR THE ALTERNATOR IS CONTROLLED THROUGH AN "OIL PRESSURE CONTROL UNIT" LOCATED IN THE FUSE PANEL ON THE DRIVER'S SIDE. IF THIS UNIT IS DEFECTIVE, THE ALTERNATOR WILL NOT CHARGE IN SPITE OF THERE BEING POWER AT THE "L" TERMINAL OF THE ALTERNATOR PLUG.