TECH TIP FOR JULY, 1995

A REBUILDER FRIEND OF MINE REPORTS THAT ONE OF HIS CUSTOMERS WAS HAVING TROUBLE WITH A 1993 FORD EXPLORER WHERE THE STARTER WOULDN'T WORK. AFTER REPLACING THE ORIGINAL STARTER WITH A REBUILT, ALL HE COULD GET WAS A "CLICK". EVERYTHING APPEARED CLEAN AND NEW BUT A VOLTAGE DROP TEST SHOWED ONLY 4-5 VOLTS GETTING THROUGH TO THE STARTER. ALL THE CABLES "LOOKED" GOOD BUT A VERY CAREFUL, INCH BY INCH, INSPECTION REVEALED A VERY SLIGHT BULGE IN THE POSITIVE CABLE NEAR THE STARTER. ONCE CUT OPEN THE GREEN FUZZY STUFF, THAT WAS ONCE THE CABLE,WAS REVEALED TO THE WORLD AND THE CAUSE OF THE "NO START'HAD BEEN DISCOVERED.

THERE ARE A COUPLE OF "TRUTHS" ILLUSTRATED HERE. FIRST, ONLY GOD AND/OR SUPERMAN CAN DETERMINE THAT A CABLE IS GOOD BY LOOKING AT IT (AND A BRIGHT TEST LIGHT DOESN'T COUNT EITHER). SECONDLY, THIS WAS A 1993 VEHICLE, SO EXPECT MORE CORROSION RELATED PROBLEMS ON FORD VEHICLES AS THEY AGE.

WHILE DOING THIS TECH TIP, I BECAME INTRIGUED WITH VOLTAGE DROP TEST & THE USE OF TEST LIGHTS TO CHECK CIRCUITRY. SO I TOOK A PIECE OF 14ga WIRE ABOUT 18" LONG AND REMOVE THE INSULATION. BY TWISTING THE ENDS OF THE INDIVIDUAL PIECES TOGETHER I OBTAINED A PIECE OF WIRE OVER 18 FEET LONG BUT ONLY 1 STRAND THICK. I HOOKED ONE END TO GROUND AND THE OTHER TO THE CLIP END OF MY TEST LIGHT. WHEN I TOUCHED TO TEST LIGHT TO POWER IT LIT UP BRIGHTLY. I ASKED SEVERAL PEOPLE TO TELL ME WHEN I HAD THE LIGHT HOOKED DIRECTLY TO POWER OR WHEN IT WAS GOING THROUGH MY 18' LONG JUMPER WIRE, AND NOT ONE PERSON (ME INCLUDED) COULD TELL. THIS LEADS ME TO STATE WITHOUT FEAR OF CONTRADICTION THAT A TEST LIGHT WILL ONLY TELL YOU IF THERE IS CONTINUITY, NOT IF THE WIRE IS ABLE TO DO ANYTHING.

I THEN LOOKED TO SEE IF THERE WAS A VOLTAGE DROP ACROSS MY 18' LONG JUMPER WIRE. NOW, FIRST YOU MUST REMEMBER THAT MY WIRE WAS MADE UP OF INDIVIDUAL PIECES WHICH WERE TWISTED TOGETHER, AND THAT EACH JOINT WILL PRODUCT A VOLTAGE DROP OF SOME VALUE. SO I HOOKED THE WIRE UP TO A BATTERY WHICH HAD AN OPEN TERMINAL VOLTAGE OF 12.15 AND READ THE VOLTAGE AT THE OTHER END WHICH WAS OF COURSE 18' AWAY. THE VOLTAGE INDICATED BY MY DVM WAS 12.15V. IN A PAST TECH TIP, I STATED THAT YOU COULDN'T DO A MEANINGFUL STATIC VOLTAGE DROP TEST AND THIS SHOULD PROVE IT. IF YOU DO GET A READABLE VOLTAGE DROP ON A STATIC TEST, YOU HAVE A HUGE PROBLEM.

MY COMPANY (AND ALL REPUTABLE REBUILDERS) SUBSCRIBE TO AS MANY TECHNICAL PUBLICATIONS AS WE CAN FIND, IN AN ATTEMPT, SOMETIMES WITHOUT MUCH SUCCESS, TO STAY SOMEWHAT CURRENT WITH WHAT IS GOING ON IN THE INDUSTRY. IT IS FROM THESE PUBLICATIONS, CONVERSATIONS WITH FELLOW REBUILDERS, AND STORIES TOLD ME BY MY CUSTOMERS, THAT I GET MOST OF THE INFORMATION WHICH APPEARS IN THE "TECH TIPS". THE PURPOSE OF THE "TECH TIPS " IS TO GET THAT INFORMATION OUT TO AS MANY PEOPLE AS I CAN, AND IT IS NOT IMPORTANT TO ME TO LIST THE SOURCE OF THE INFORMATION. BUT IF YOU WISH TO KNOW WHERE I GOT A SPECIFIC PIECE, JUST CALL AND I WILL BE GLAD TO SHARE THAT INFORMATION TOO!

A FORD TECHNICAL BULLETIN, DATED JANUARY/94, WARNS THAT ON 1987-93 BRONCO, ECONOLINE, AND F150-350, AN ALTERNATOR ETC. DRIVE BELT WAS USED THAT HAD A FABRIC BACKING. APPARENTLY THIS BACKING COULD TRAP ABRASIVE PARTICLES AND CAUSE PREMATURE IDLER PULLEY WEAR. THE CURE IS TO REPLACE THE BELT WITH ONE WHICH DOESN'T HAVE A FABRIC BACK, AND TO CHECK THE IDLER PULLEYS FOR WEAR. THE NOMINAL DIAMETER OF THE PULLEYS IS EITHER 90MM (3.453") OR 76MM (2.916"). IF THEY ARE WORN TO 88MM (3.377") OR 74MM ( 2.839") OR LESS THEY SHOULD BE REPLACED.

SOME 1992-93 CHEV M/L VANS EQUIPPED WITH 4.3L ENGINE (L35) (VINW), MAY EXPERIENCE A HESITATION OR LACK OF POWER WHEN ACCELERATING UNDER HOT DRIVING CONDITIONS. THERE WILL BE NO CODES STORED, THE ENGINE WILL RUN FINE ALMOST ALL THE TIME, FUEL ECONOMY WILL BE NORMAL, AND THE ENGINE WILL NOT MISS, SURGE OR HAVE A ROUGH IDLE.

A POSSIBLE CAUSE IS THE OUTLET DUCT BETWEEN THE AIR CLEANER & THE THROTTLE BODY MAY NOT HAVE ENOUGH RIGIDITY TO WITHSTAND THE A RAPID PRESSURE DROP DURING HOT CONDITIONS AND MAY DISTORT. THERE IS A EARLY STYLE AND A LATE STYLE OF OUTLET DUCT. IF THIS MATCHES YOU CUSTOMER'S COMPLAINT, CHECK TO SEE THAT THE VEHICLE IS FITTED WITH OUTLET DUCT # 2509916 AND THE PROBLEM MAY BE SOLVED.