Re: HELP, Bizarre Electrical Poblem.

[Andrei Talalaevskii <andrei@insti.physics.sunysb.edu>]

On Wed, 26 Aug 1998, Chad Frederick wrote:

> Before this never an electrical problem since I have
> had the car.  I do not get it.  If this sounds like there may be a
> diagnosis for this please drop me a line. I do not know where to start to
> fix this.  It looks like my road trip this weekend may be out.  damn. 
> 
> 86 4kcs Q
> Chad Frederick

I am sure the car will be fine and your weekend trips will not be 
canceled because you must be a really lucky person if you haven't yet had 
electrical problems with this car. In my '84 4kq 80% problems are electrical 
and I am not alone at this. When I bought this car, the auxiliary lights were
absent but the wiring was in. After I got these wires out together with 
remainders of other systems the previous guy installed and then 
vandalized, my life became _much better_. Of course I had an extreme case 
because the guy didn't even bother to  insulate wire ends after he 
took aux. lights out.

Most likely you simply made a mistake when putting the wires in and 
introduced some charge leak to ground. Check for that!

> All I can think is it might be a voltage regulator, but I am not sure. 
> 
Unlikely voltage regulator died exactly the day you added new wires. To
check the regulator you may first charge the battery well from other car
or battery charger. Disconnect the alternator with regulator and have the
car run on the battery. If you battery is not very old or very bad you
must have at least several minutes to see that everything is working fine.
If everything is fine, which I doubt, look for the problem in the 
alternator/ V. regulator, or their connection.

Do not do the opposite (run the car on alternator with disconnected
battery, especially if you suspect V regulator). Voltage spikes that may
otherwise kill other electrical components are dampened by battery.
Example, I noticed the oscillations of lights brightness and of fuel pump
sound level. When looked with the voltmeter, I saw that
voltage on the regulator output oscillated up to 17 Volts. Then I
disconnected the battery I observed spikes up to 60 Volts! I was very
lucky that I didn't kill a fuel pump or anything else. The problem was
indeed in V regulator. 

As for your problem, my advise is to look in the daylight for 
any accidental short-circuits, etc, everywhere you made any interference 
when installing your lights. Best of all try to find it by simply looking.
Sometimes it helps to disconnect cables from the battery and measure the 
resistance from the end of one cable to the end of another. It should be 
large. If it is tens or hundreds of Ohms only, remove one fuse from the 
fuse panel and see whether the resistance goes up. If yes, the leak is in 
the circuit associated with this fuse. If no, put the fuse back and 
continue with the next one. Etc...


These leaks, shortcuts, bad connections have a feature of going away and
coming back until located and fixed. That's why your car might have been
running well for several minutes after a jump-start. 


HTH,

Andrei