In article <3FD4E0DF.F24CF6D7@neo.rr.com>,
"N.E.Ohio Bob" <rgstroud@neo.rr.com> wrote:

> I think you need a simple volt, amp, load test at your corner parts
> store. Follow their advise. bob

Yes, perhaps. You're right, I didn't do the full field tests on the
Alternator, but remember, I was following the Honda Service test
procedures. They specified testing for certain voltages through the ECU
from the Alternator harness *first* - and that test failed.

And Bob, I appreciate the suggestion; believe me, I wish I could just
turn it over to someone with all the proper test equipment/new parts.
But I'll be lucky if I can afford the parts I need... there's nothing in
the budget for someone else's labor.

I was hoping these symptoms would be common, and someone here would know
where the likely failure is - the computer or some load sensor, etc...

Thanks,

--Charlie Henderson

> Charles Henderson wrote:
> >
> > 1990 Civic DX, 4 Dr., 5 Sp., 1500cc
> >
> > I've got the Battery light on in the dash pretty much all the time now.
> > It was intermittent, not coming on for a half hour or so after startup,
> > and either coming on or going out under certain engine load conditions,
> > but now it's there all the time.
> >
> > Honda Service Manual has an Alternator testing procedure that first
> > begins by removing the main connector from the Alternator and checking
> > for voltage to ground at two different pins inside the connector.
> >
> > Unfortunately, mine fails the second of those voltage tests, and in that
> > case the test procedure refers you to the ECU troubleshooting section at
> > that point. Which is a bit of a problem because I don't have the special
> > interface cable needed to access the ECU circuits for test purposes, and
> > get this: the test procedure for the ECU says "Substitute known-good
> > ECU; if problem disappears, replace ECU" at various points in the
> > procedure.
> >
> > Hmmm. I haven't priced it officially yet, but that thing costs in the
> > neighborhood of $250 bucks! I can't afford to buy one just for testing
> > and troubleshooting!
> >
> > And if I *had* a known-good ECU, what would I need a testing procedure
> > for in the first place? Swapping it out would *BE* the testing procedure!
> >
> > ;-)
> >
> > I think the problem is that the ECU has an economy circuit in it that
> > shuts down the Alternator under certain load conditions to save fuel.
> > Pretty neat idea, except when it malfunctions!
> >
> > My question: How can I determine for certain whether it is the ECU
> > malfunctioning, or if it's some other load/condition sensor giving it
> > faulty data? And I suppose it still could be the Alternator itself...
> >
> > Keep in mind I don't have a "known-good" ECU to follow the official
> > diagnostic procedure, and I'm not sure if I can go buy one, use it for
> > testing, and return it if it turns out not to be the culprit.
> >
> > Any ideas?
> >
> > ;-)
> >
> > Thanks,
> >
> > --Charlie Henderson