I have a '97 Accord EX.

Is the voltage regulator internal or external on our cars?

My alternator is putting out 0.5V--yes, 1/2 V at idle. I disconnected the battery/fuse line from the alternator stud and cranked the car up to see what the alternator alone was putting out. I got 0.5V! :eek:

And the 0.5V kinda makes sense b/c I was getting 11.9V at the battery with the engine off; 12.4V at the battery with the engine on. So it's like it was adding the 0.5V from the alternator for the total of 12.4V while engine running.

Other readings I got were:

0.36V @ alt w/ engine on and NO GREEN HARNESS PLUGGED IN
>1.0V @ alt w/egnine on and revved up w/ NO GREEN HARNESS PLUGGED IN

0.52V @ alt w/ engine on and Green harness plugged in
14+V @ alt w/engine on, green harness plugged in, AND ENGINE REVVED.

Anybody know what the hell could be wrong with my charging system?

Some other readings I took on the green 4-wire harness were:
6.23V between white/blue and white/red w/ engine on
6.23V between black/yellow and white/red w/engine on
no voltage readings between the 4th wire and any of the the other wires.

 

the voltage regulator is internal to the alternator on our cars. that harness is: field wire (ignition power), and a couple for the ELD. ELD = electrical load detector and is what switches the alternator from low to high output mode. A lot of asian and euro Honda's lack ELD's, but thats besides the point.

Have you checked all the fuses?

I would pull the alternator and take it to the parts store... see what she does. You'll know in about 5 mins if its bad or not. If its good I would ensure all the wiring is intact and if it is you may have to replace the engine compt. fuse box as that is where the ELD is located and is intrigal to the fuse box.

Are you showing any check engine lights? ELD will throw a code often if its having problems.

 

There's gotta be something going on with the ELD. I did check my fuses and I had actually blown the 100A fuse at the main fuse box that supposedly leads to the battery. (I was still getting power to the fuse box b/c I have an 0 ga power cable from the alternator directly to the battery.)

I must confess that I have arced the old alternator a couple of times--first time this year when I was removing it to do the timing belt. I didn't disconnect the battery and the thing sparked to hell. That could have been the arc that blew the 100A fuse. I replaced the 100A fuse yesterday, but I'm still having that low voltage problem.

I have a very big stereo in my accord--capable of pulling almost 200A! I just recently upgraded to a 140A alternator this weekend. But this problem that I'm having is not about the alternator b/c it was going on with the OEM alt, junkyard reman alt, and the Autozone Duralast 90A alt that have all been on my car in the last 6 months.

what exactly is the ELD. How can I check it. No, I don't have ANY CEL codes.

 

Unfortunatly I dont have my electrical trouble shooting manuals here, but tonight I'll look and see what the testing procedures are (if any). ELD is just a solid state piece of electronics that detects the current load (if the light .. ac .. etc) are on and adjusts the output voltage of the alternator accordingly [sic].

 

It could be my ELD.

There's some more testing procedures outlined here in my Haynes manual. Since the main 100A fuse was already blown, the ELD could've been blown, also.

My buddy just asked if my computer was damaged as well.

Salvage yard says $125 for a main fuse box (can't get just the ELD--have to get entire under-hood fuse box). should've just disconnected the battery cables.


Modified by JiggaFan at 1:56 PM 7/24/2003

 

The ECU does talk to the ELD. Basically the ELD tells the ECU that its now going into highoutput mode and to please idle the car a lil higher (ever notice how you turn your headlights on and then the idle picks up a tad? Thats why... to compensate for the extra load on the alternator).

Electrical troubleshooting says: ELD is a code 20 (but you're not seeing any codes). Tesing proceedures for a ELD:

1. disconnet the 3 pin ELD connector on the drivers front side of the fuse box (underhood).

2. with the ignition switch ON (car not running) there should be battery voltage between the black & yellow (+) and the black (-) wire terminals.

3. if there is no voltage check for:
- an open in the black & yellow wire between the dash fuse box and under-hood fuse box.
- poor ground

* if there is voltage goto step 4.

4. Check for voltage between the green & red wire terminal and the body of the car with the ignition switch still on.. There should be approxemetly 5 volts.

* if the voltage is as specified goto step 5.

5. check the voltage between the green & red terminal and body ground same as step 4 except with the headlights (low beam) on. there should be approximately 2 volts.

- if te voltage is not as specified replace the relay/fuse box. ELD is not available seperatly.

- if the voltage is as specified ELD unit is ok.

-------------

if that check out OK its either a shot wire, bad alternator or bad ECU.

 

Pffft. Try cleaning the batttery posts. :

I also adjusted my idle up to about 1000 RPM's. When I last repaired my Fast Idle Thermo Valve, I may not have put the accelerator cable back on to it's necessary tightness. I kinda just followed the worn thread pattern in the cable and figured it would go right back in place where the threads looked the newest/cleanest (b/c they had been covered up, right?).

Well, I took alot of slack out of that cable and got the alternator continuously pumping out 14.37 - 14.41 Volts.

But then I connected the battery (I have a nice little battery terminal cover by Tsunami easy connection of my 1/0 power cables) and my voltage dropped to 14.2 Volts? Somehow, it seems my battery (Optima YellowTop) is presenting a constant drain on the alternator. I'm gonna fully recharge it with my battery charger to see if that helps.

Thanks. I went through those same ELD testing procedures using my Haynes manual and I was relieved to find it was okay.

Now one thing I did notice. In the alternator testing part, it says to connect the positive battery terminal, then with the negative terminal disconnected, touch a test light to the negative battery post and the negative terminal. If the light glows brightly (will glow dimly b/c of normal drain from the ECU), then there is a short somewhere in the cars electrical system. Check all fuses to help identify the short. Well, I thought for sure that my light was glowing very bright. But my DMM said it was 9.0 V between the battery post and terminal, where as there was 12.0+ Volts between the negative battery post and postive post/terminal.

So is that 9.0V "normal ECU drain" and I just interpreted "glow brightly" wrong? Or is there a short somewhere. If there is a short somewhere, then it's in my excessive stereo/alarm/lighting wireing b/c I checked all the OEM fuses and the light never got dimmer.

Thanks again for your input and concern.