Alternator help/questions '89 Metro

[doviatt]

soD

You got me thinking. (not always a good thing). So I made measurements again today at lunch.

B+ terminal on alternator and Batt neg terminal. Engine OFF. 12.2V
B+ terminal on alternator and Strut mount (chassis ground). Engine OFF. 8.2V (should be 12.2V also)

Loosen Batt neg to chassis gnd wire and re tighten chassis screw.
Run errands at lunch...then more measurements.



B+ terminal on alternator and Strut mount. Engine ON 17.2V
B+ terminal on alternator and Batt neg terminal. Engine ON 18.7
B+ terminal on alternator and Batt neg terminal. Engine OFF 11.7.
:-$

Realized I didn't measure just batt status so I repeat measurements:
Batt pos to neg. Engine OFF. 12.05V
B+ alternator to Batt neg. Engine OFF 11.37V
B+ alternator to Strut. Engine OFF 10.93

Batt pos to neg. Engine ON. 11.8V (no difference with engine speed)
B+ alternator to Batt neg. Engine ON. 18.4V-19V
B+ alternator to Strut. Engine ON. 18V

It appears that I should loosen and clean and re tighten all grounds. This made a difference. Is it still broke though???

[Johnny Mullet]

Double check the battery. It could be internally shorted and the parts store you got it from can test it to verify. Otherwise, you have a missing or bad connection. Any recent work done to the car before this issue developed?

[doviatt]

This is a new battery (2 weeks old). My previous one was also purchased new just 9 months ago.

Recent work? No. The car was a basket case when I got it. Hadn't been maintained. Needed everything. After replacing everything (batt, alt, muffler, brakes, heater core, timing belt, tires, filters, oil, coolant) it has been great for the last 9 months. When I got it, it had a mondo sized truck battery in it. Probably to mask this problem. But, with new battery and alternator within 1 week of buying the car everything seemed fine.

Odd but possibly related issue is I noticed (when I got it) main fuse 60A was missing and a heavy gauge stranded wire was stuffed down in its place. I also replaced that after I got it with a proper fuse. This is probably the one between the alt and batt. No issues though. Another was a rear stereo speaker terminal shorting out which I fixed. Another is rear defroster doesn't work and spade connectors on rear window look over heated. No fuses have blown though. This list makes it sound like an electrical Frankenstein monster. Odd that problems have been dormant for so long lately.

I am going to have the battery and the alternator tested. I have a feeling they will try to tell me they are both bad rather than try to help me find out what is wrong. I never believed them when they told me my last alternator tested bad. After all it was putting out volts...doing it's job. Exact same symptoms as current issue.

I think your statement of missing parts, bad connection is prime candidate for continued investigation. I'll follow the connection between alt and batt and see if anything turns up. If is is in fact just a straight connection I'll put in a new heavy gauge wire.

Thanks Johnny Mullet!
I can't complain about the MPG though. Hey, join us on Team Metro (teams competition). We could use you.

I'll update if anything else odd or interesting turns up during my investigation.

Thank you all for your help. I'm learning a lot and I'm always open to more suggestions. If anyone thinks of something new to try...post away.

[doviatt]

I think I have it fixed. I ended up buying a 4 foot long 6 gauge wire (probably overkill) and crimped on some heavy terminals. Went straight from Alternator out to Battery positive terminal.

Before starting I measured 13.2 V on Battery (I had it on the charger all night). After wire hook up and starting I measured an appropriate 14.something volts on battery.

I then took it to the auto parts store for a charging system test. Everything tested just fine. Battery is great. Alternator and Voltage Reg is just fine. All this trouble for old wires. Live and learn. I wouldn't have had to buy the last battery and alternator 9 months ago had I known what I know now.

Thanks for all your help guys.

I'll know for sure when I give it the 500 mile drive to work routine next week. But I suspect every thing is cool.

P.S. now my radiator is leaking... oh well it never ends. I'm ready to tackle this next project. It will be a cake walk compared to the heater core replacement. I think I'll try some stop leak first.

[some_other_dave]

Just a note: It is more likely for the ends of the wires (the connectors particularly) to have problems than the wires themselves. Usually if you cannot see green corrosion (assuming the wires have not been "tinned"; probably some other color if they are) and if the wire flexes normally for a wire of that thickness, then the wire is still good. The ends of the wire tend to be exposed to more dirt and water than the middle is, which is where the problems usually come from.

-soD

[dwtaylorpdx]

radiators.com

I got a fair deal from them...

Dave

[doviatt]

Originally Posted by dwtaylorpdx

radiators.com

I got a fair deal from them...

Dave

Hey thanks. They responded very quickly with pricing and availability. I will order from them when I'm ready (defined as the careful alignment of time to work on it, available funds$$$, and hopefully mild weather).
The stop leak is working as the current band-aid. I know it is only temporary but it gives me time to shop around and to it right.


P.S. All. the electrical repair (wire replacement) is still working as it should.