TECH TIP FOR JULY, 1993

SOME HONDA ALTERNATORS HAVE BEEN CAUSING CONCERN BECAUSE THEY WILL START TO CHARGE AT THE NORMAL 14.5 VT RATE AND THEN DROP OFF TO ABOUT 12.5 VT. ON COMPUTER CONTROLLED CARS THIS IS EXACTLY WHAT IS SUPPOSED TO HAPPEN. HOW IT HAPPENS IS THAT, THE "C" TERMINAL FUNCTION OF THE REGULATOR HAS BEEN GROUNDED BY THE COMPUTER, CAUSING THE REGULATOR TO DROP THE ALTERNATOR OUTPUT TO APPROX. 12.5 VOLTS AND 5 AMPS.

THE ALTERNATORS INVOLVED CAN BE IDENTIFIED BY LOOKING FOR THIS"C" TERMINAL ON THE REGULATOR PLUG. THESE ALTERNATORS COME IN 3 OR 4 TERMINAL VERSIONS, MANUFACTURED BY NIPPONDENSO ORMITSUBISHI, AND CAN BE FOUND ON BOTH CARBURETTED OR FUEL©INJECTED VEHICLES FROM ABOUT 1984 ON.

THE COMPUTER DROPS THE ALTERNATOR OUTPUT UNDER THE FOLLOWING CONDITIONS:

* AN ELECTRICAL LOAD OF LESS THAN 10 AMPS.
* VEHICLE SPEED BELOW 40 KM/H.
* ENGINE SPEED BELOW 3600 RPM.
* COOLANT TEMPERATURE ABOVE 140 DEG.
* AIR CONDITIONER OFF.
* INTAKE TEMPERATURE ABOVE 65 DEG.
* BRAKE SWITCH OFF
* FUEL CUT OUT CONTROL FUNCTION OFF.

WHEN ALL THESE CONDITIONS ARE MET, THE COMPUTER WILL DROP THECHARGE RATE TO 12.5 VOLTS.  AS YOU CAN IMAGINE THE MOST LIKELYPLACE TO FIND ALL THESE CONDITIONS BEING MET, IS IN YOUR SHOPWHILE YOU ARE CHECKING THE CHARGING SYSTEM.

UNDERSTANDING THE SYSTEM IS IN THIS CASE ABSOLUTELY VITAL TOOBTAIN A PROPER DIAGNOSIS. THE EASIEST WAY TO MAKE THE SYSTEMSTART TO CHARGE AGAIN AT THE PROPER RATE IS STEP ON THE BRAKE.

1986-1989 ACCURA INTEGRAS WHICH REQUIRE EXTENDED CRANKING BEFORE THE CAR WILL RESTART, WHEN VERY HOT, MAY HAVE A DEFECTIVE FUEL PUMP CHECK VALVE OR PRESSURE REGULATOR. ACCURA RECOMMENDS THE FOLLOWING STEPS TO ISOLATE THE PROBLEM:

RELIEVE THE PRESSURE IN THE FUEL SYSTEM AS OUTLINED IN THE       REPAIR MANUAL.

* TEE A PRESSURE GAUGE INTO THE FUEL SYSTEM.
* START AND ALLOW THE VEHICLE TO RUN FOR ABOUT 30 MIN. AND MAKE     SURE THE FUEL PRESSURE HAS STABILIZED.
* SHUT OFF THE VEHICLE.

RESIDUAL FUEL PRESSURE SHOULD REMAIN BETWEEN 30©35 psi. FOR THEFIRST 5 MIN., AND NOT DROP MORE THAN 10psi IN THE NEXT 10 MIN. IFTHE RESIDUAL FUEL PRESSURE IS NOT WITHIN THESE GUIDELINES, THEFUEL PUMP OR PRESSURE REGULATOR IS DEFECTIVE.

IF THIS SITUATION IS NOT CORRECTED, THE STARTER WILL FAIL QUICKLYAND ANY REPLACEMENT STARTER WILL NOT LAST, WHICH CAN LEAD TO SOME UPSET CUSTOMERS, MECHANICS AND SUPPLIERS.

SOURCE: AUTOMOTIVE PUBLICATION CO. / A.P.R.A. CONNECTION.ÄÄ

CONTRARY TO A COMMONLY HELD OPINION, THE NECESSITY TO SHIM THE DELCO "PAD MOUNT" STARTERS (FASTEN WITH 2 BOLTS UP FROM THE BOTTOM), IS NOT A PROCEDURE DREAMED UP BY REBUILDERS TO COVER UP FOR SLOPPY WORKMANSHIP.

ALLEGEDLY THE PROBLEM HAS ARISEN BECAUSE G.M. ALLOWED EACH ENGINE PLANT TO DEVELOP AND ARRANGE SUPPLY OF ITS OWN STARTER DRIVE END HOUSINGS. THIS ALLOWED VARIATIONS IN TOLERANCES OF UP TO .100", THIS BECAME WORSE WHEN THE AFTERMARKET STARTED MAKING HOUSINGS BECAUSE THEY JUST COPIED WHAT WAS AVAILABLE FROM G.M., AND TO FURTHER COMPOUND THE PROBLEM, ALL THESE DRIVE END HOUSINGS HAD THE SAME PART NUMBERS REGARDLESS OF WHAT PLANT THEY CAME FROM.

REGARDLESS OF HOW THE PROBLEM AROSE, THE FACT REMAINS THAT SOME OF THESE STARTERS REQUIRE SHIMS, AND THE FACT THAT THE OLD ONE DIDN'T HAVE ANY DOESN'T MEAN ANYTHING. SIMILARITY THE FACT THAT THE OLD ONE HAD SHIMS DOESN'T MEAN THE NEW ONE REQUIRES THEM.

THE PROCEDURE IS TO INSTALL THE STARTER WITH SHIMS AND THEN AFTER ACTIVATING THE SWITCH TERMINAL (WITH THE MAIN BATTERY DISCONNECTED FROM THE SOLENOID, PLEASE), MEASURE THE SPACE BETWEEN THE TIP OF THE FLYWHEEL TOOTH AND THE VALLEY FORMED BY STARTER DRIVE TEETH. THIS DISTANCE SHOULD BE BETWEEN .020" & .060", A GOOD SUBSTITUTE FOR PIN GAUGES IS A PAPER CLIP, WHICH IS ABOUT .032" DIA.

PLEASE REFER TO THE ATTACHED SHEET FOR MORE CLARIFICATION AS TO PROCEDURE AND REASONING. WHAT IS REALLY OBVIOUS IS THAT THERE IS MORE TO PROPERLY INSTALLING A G.M. STARTER THAN MANY THINK, AND THAT THE PEOPLE WHO WROTE THE FLAT RATE MANUALS NEVER DID IT RIGHT.