TECH TIP FOR DECEMBER, 1994

THIS WILL BE A RATHER COMPLICATED TECH TIP, BUT I HOPE TO MAKE IT CLEAR AND WOULD ASK THAT YOU STRUGGLE THROUGH IT.

BEGINNING IN THE 1990 MODEL YEAR, GM STARTED USING WHAT IS CALLED THE SD SERIES OF STARTER. THIS IS A " SMALL BODY" UNIT, WHICH CAN BEST BE IDENTIFIED BY THE FACT THAT THERE IS A TWO LEGGED CLAMP ASSEMBLY, WHICH FITS OVER THE SOLENOID, AND IS HELD BY TWO BOLTSTO THE STARTER HOUSING.

ALMOST FROM THE BEGINNING OF USE, THERE HAVE BEEN COMPLAINTS OF INTERMITTENT "NO START", WHERE THE CUSTOMER HEARS THE SOLENOID BUT NOTHING HAPPENS. GM ISSUED A BULLETIN RECOMMENDING THAT THE SOLENOID BE REPLACED, BUT A GM DEALER I KNOW, SAID THAT THEY ALWAYS REPLACED THE PLUNGER AS WELL. HAVING EXAMINED SEVERAL PLUNGERS I AGREE, AND AS A RESULT, IF NOTHING ELSE IS WRONG WITH THE STARTER, CAN RECOMMEND A REPAIR PROCEDURE OF REPLACING THE SOLENOID AND PLUNGER ASSEMBLY. IT IS IMPERATIVE THAT YOU USE THE RECOMMENDED GREASE (AVAILABLE ONLY FROM GM) ON THE SOLENOID BORE. DO NOT USE ANYTHING OTHER THAN THE RECOMMENDED GREASE, OR BE PREPARED FOR THE SOLENOID TO STICK.

AFTER THE 1990 MODEL YEAR, GM MADE A CHANGE IN THE MOUNTING OF THIS STARTER. UP TO AND INCLUDING THE 1990 MODEL YEAR THIS STARTER REQUIRED A MINIMUM OF 2mm OF SHIMS, BUT AFTER 1990 YOU CAN'T USE ANY SHIMS. GM HAS STAMPED ON THE FRONT OF THE HOUSING WHERE THE SOLENOID ATTACHES, THE WORDS "NO SHIM". WHEN CHANGING THIS STARTER, YOU MUST CHECK TO SEE IF THE SHIMS ARE REQUIRED OR NOT, OR THE STARTER WILL FAIL. AS A SIDE NOTE, THIS "NO SHIM" SITUATION APPLIES TO OTHER GM "PAD MOUNT" STARTERS AS WELL. WE RECENTLY HAD A CUSTOMER DESTROY A 6.2L STARTER IN LESS THAN 2 MONTHS BY INSTALLING SHIMS ON A "NO SHIM" STARTER. ( AND NO, I DIDN'T WARRANTY IT).

THE SAME STARTER IS INVOLVED IN A CHEVROLET/GEO TECHNICAL BULLETIN FROM AUGUST, 1993. IN THIS CASE THE CUSTOMER ALSO COMPLAINS OF AN INTERMITTENT "NO START". THE VEHICLES INVOLVED ARE LUMINAS (3.1L & 3.4L), 1991, 93. IF ALL ELSE FAILS TO LOCATE THE PROBLEM, CHECK TO SEE IF AN ALARM SYSTEM HAS BEEN INSTALLED. EVEN WITH THE "GOODWRENCH" SYSTEM, THE WIRING FROM THE CONTROL MODULE TO THE SAFETY/NEUTRAL SWITCH MAY NOT BE HEAVY ENOUGH TO CARRY THE TOTAL CURRENT REQUIREMENTS OF THE SOLENOID UNDER ALL CONDITIONS. THIS WIRE MUST BE OF AT LEAST 10ga.

GM HAS AN "ALARM SYSTEM REWORK" PROCEDURE OUT, WHICH IS VERY INVOLVED AND WILL COST SOMEBODY A PILE OF MONEY IF REQUIRED. IF YOU HAVE FIXED THE ALARM SYSTEM, BUT THE PROBLEM PRESISTS, OR IF THERE WAS NO ALARM, THEY RECOMMEND THAT YOU ALSO CHECK THE FOLLOWING:

A) POS & NEG CONNECTIONS AT THE BATTERY FOR CLEANLINESS AND        TIGHTNESS.

B) GROUND CONNECTIONS AT THE BLOCK FOR THE SAME.

C) ALL CONNECTIONS AT THE STARTER.

D) THAT THE BATTERY IS GOOD AND FULLY CHARGED.

IF ALL OF THIS IS FOUND TO BE CORRECT, THEN DO THE FOLLOWING: USING A DIGITAL MULTIMETER, CHECK THE VOLTAGE AT THE "S" TERMINAL OF THE STARTER, WHILE ATTEMPTING TO START THE VEHICLE. ( THIS MUST BE DONE WHILE THE VEHICLE IS EXPERIENCING A "NO START", NOT DURING A GOOD START.) IF THE VOLTAGE IS LESS THAN 9.0 VT, CHECK FOR A HIGH RESISTANCE CONNECTION IN THE WIRING, CONNECTIONS, IGNITION SWITCH, OR PARK/NEUTRAL SWITCH.

IF THE VOLTAGE IS GREATER THAN 9.0 VTS, REPLACE THE STARTER WITH THE NEW AND UPDATED (READ BIG $$) VERSION OF IT. (P/N10455060 FOR 3.1L & P/N 10455061 FOR 3.4L) THESE ARE BOTH "NO SHIM" STARTERS. OUR EXPERIENCE SO FAR HAS BEEN THAT, RATHER THAN A NEW STARTER, THE REPLACEMENT OF THE SOLENOID AND PLUNGER ASSEMBLY WILL USUALLY CORRECT THE PROBLEM.

!!NOTE!! IF THE SOLENOID IS HOT TO THE TOUCH, USE A VALUE OF 9.5 VT.  THE 9.0 VT VALUE IS IF THE SOLENOID IS AT ROOM TEMPERATURE.