Foreign service

Motor, Jul 1999 by Marinucci, Dan

Dan continues his series on transplanted Delco CS-series alternators by looking at a third import manufacturer that uses the troublesome unit-Honda

In my last two columns, I discussed Delco CS-series alternators that are original equipment on some Toyotas and Isuzus. This month, we'll examine Delco usage on Hondas and Acuras. Let me clarify something about Isuzu char, nz systems first. Each Delco alternator we cover in this series has a special voltage regulator that "adapts" it to a specific Japanese vehicle. This doesn't apply to Isuzu trucks and sport/utilities equipped with General Motors engines, however. If you see a Delco alternator on a GM engine in an Isuzu, you know it's wired like and works just like its domestic counterpart!

Now on to Hondas and Acuras. You'll find Delco CS 130D alternators on Ohio-built Hondas and Acuras equipped with the 3.0-liter V6. These applications include 1998-99 Accords and mechanically similar 1997-99 Acura CLs.

The "D" in CS 130D refers to the alternator's dual internal fans. As we explained in the May issue, the 130D is an updated, upgraded version of the notorious CS-series alternator used on zillions of domestic GM products. Remember, the traditional domestic CS-series has a long, rectangular harness connector with terminals P, L, I, S or P. L. F S.

At first glance, the Honda/Acura CS 130D looks just like its domestic counterpart. The first difference you'll notice is a Delphi label on the housing. The company that used to manufacture Delco-Remy passenger car starters and alternators is now called Delphi.

The second difference is a square harness connector containing terminals IG, L, FR and C (see photo below). If this combination sounds familiar, it's because we covered it in a previous column. Note that beginning with the 1998 Civic. Honda equipped most of its cars with a four-terminal alternator. The good news is that the vast majority of them are Nippondensos, a few are Mitsubishis.

Delphi uses a vehicle-specific voltage regulator to "Honda-ize" its CS 130D for the Accord and CL. Because you test this hybrid alternator just like a common four-terminal Honda unit, we'll review operation of terminals IG, L, FR and C.

Battery voltage must be present at the IG (Ignition) terminal whenever the ignition switch is on or the engine is running. Powering up IG turns on the voltage regulator, which operates the field circuit. Turning on the field circuit makes the alternator charge.

The alternator should charge when you carefully jumper battery voltage to IG (assuming there's a good connection between the positive battery post and the alternator's B terminal). If it charges, look for a wiring problem on the vehicle. If it doesn't charge, remove the alternator because the problem is inside the unit.

L (Lamp) operates the charge indicator lamp by grounding it. The voltage regulator should unground L when the alternator begins charging, shutting off the idiot light.

FR (Field Circuit Monitor) is a 5-volt reference voltage the ECM sends to the voltage regulator whenever the ignition is on or the engine is running. FR is connected to the ground side of the field (ground side of the rotor). Every time the voltage regulator grounds the rotor, it turns on the field circuit and makes the alternator charge. Grounding the rotor also pulls FR voltage downward.

The greater the electrical demand, the longer the regulator grounds both the rotor and FR voltage. Of course, electrical load influences the ECM's decisions. One way the ECM senses electrical load is by monitoring how long FR voltage remains low. Another way is through the Electronic Load Detection (ELD) signal.

C (Computer) is the terminal that shifts this alternator's unique voltage regulator back and forth from normalcharge to low-charge modes. Normalcharge mode means the alternator charges at about 14.0 to 14.7 volts. But when there's no significant load on the electrical system or the engine, the ECM grounds terminal C, limiting charging voltage to about 12.6 to 12.8 volts. The low-charge mode saves fuel during light-throttle driving.

Typically; the ECM won't ground terminal C until the engine is fully warmed up and the vehicle is moving faster than approximately 10 mph. Flooring the gas pedal, turning on the a/c or applying the brakes cues the ECM to quickly shift back to normal-charge mode.

Most Hondas using this dual-mode charging system go back to normal charging voltage by about 40 mph or by turning the headlights onto low beam. As a case in point, the two '98 Accords we checked went back into normal charge by about 43 and 47 mph, respectively. Also, just turning on the parking lights put these systems back into the normal-charge mode.

Remember that the voltage regulator on these dual-mode charging systems still operates the alternator light in the traditional way. Terminal C has no effect on the charge indicator light.

The ECM on a dual-mode Honda/Acura charging system also senses electrical load via the ELD sensor, a glorified shunt inside the main fuse panel in the right rear corner of the engine compartment. The ECM sends a 5-volt reference voltage to the ELD. Like all the earlier ELDs we've seen, this reference voltage wire happens to be green/red. The greater the current flow through the main fuse panel, the lower the ELD pulls this reference voltage.