Charging Issues

[Skibbe]

Awhile back my alternator (battery +) wire was up against my radiator, wore/melted through the insulation, and arc'd a hole in my radiator. Ever since it's been back together I've apparently had a charging issue. But I didn't drive it enough to notice until recently. I originally diagnosed a charging issue as a voltmeter was giving wonky readings off the alternator wires. I swapped in a new alternator and wired in an external regulator last weekend. I also have a new alternator-to-battery(+) wire installed.

After the new installations, I had good voltage at the battery (over 14 volts on multi meter) with the car running, so I figured everything should be good. My OTC only registered ~10 volts but I just figured I didn't get a full charge on the battery while the car was apart.

I just got home from a ~10min test drive around town and noticed the factory voltage gauge was reading low. I parked and plugged in my OTC and it confirmed battery voltage was under 8 volts ?!?!

By the time I ran inside to get a multi meter to check actual voltage across the battery, the car died in the driveway.

So, a couple questions come to mind. If the alternator was working properly, the car should keep running no matter what, right? Or could a bad battery that isn't taking a charge cause the car to lose voltage and finally die?

[turbovanman²]

Bad battery's simply load up the alternator but it will still charge properly until you shut it off. Some aftermarket external regs are pure junk, so I would simply full field the alt checking the amps and voltage too see if maybe the alt went bad or the reg did or both.

[Skibbe]

Out of the two I'd hope it's the regulator. The alternator is a brand new Bosch (Nippo style) 90 amp.

And I just ran out to make sure the belt was still on the alternator. In the middle of dinner it occurred to me that if the belt fell off it would explain a lot. But it's still there.

[turbovanman²]

Bosch sucks, I honestly have no luck with their starters and alternators, terrible craftsmanship,

[BadAssPerformance]

When you did the external regulator and re-did your harness, how did you ground the alternator?

[Skibbe]

Same ground wire that was attached to the alternator before, just removed from its plastic shroud on the alternator side.

I pulled out the '88 wiring diagrams last night, and while I put a meter on my new alternator positive wire to check continuity, it was only from the alternator to the single pin white plastic plug. It looks like there is a fusible link between that plug and the battery itself. So that fusible link will be the next think I check. It might have blown when the sparks flew the first time, though not fast enough to save my radiator apparently...

[BadAssPerformance]

Yeah, thats where I was going... hope the fusible link saved the SMEC

Radiator... Need TIG?

[Skibbe]

Yeah, thats where I was going... hope the fusible link saved the SMEC

Radiator... Need TIG?

Since the car runs with a charged battery pretty well, I assume the SMEC is generally OK.

Radiator... you already fixed it! This is from almost 2 years ago, I didn't do anything with the car last year unfortunantly.

[BadAssPerformance]

Doh! It's been too long, I forgot! LOL

I thought there was the diode or whatever in it, like the thing that used to be in the power module?

*crosses fingers* for fusible link!

[Skibbe]

Fusible link. I'm going to head to the parts store later, but if they don't have a 12ga fusible link, what size fuse should I run in one of those single fuse holders?

[BadAssPerformance]

One of the many parts stores in our hood should have one... if not, I might (not sure what gage tho)

Need to look up how manyu amps 12ga stranded is good for to find the fuse you need.

[Skibbe]

Our 8 parts stores are useless. Napa had it though. Should have gone there first.

I always forget how useful Russ's site is. He says 12ga fusible is 160 amps (!!!) in a maxi-fuse (2x80 in parallel) When I was having trouble finding the fusible link in 12ga I found the 80amp Maxi's but no holders for them.

Let me know if you want to go yarding sometime JT, I need to find a PDC out of a neon or something to get rid of these links. I hate replacing them.

Good news, it works and it's charging. Though I got the code 46 overcharging power loss light now. Does that mean I fixed it too good?

[BadAssPerformance]

160A? Wow... I think others have replaed the fusible links with regular 20A blade fuses?

[Skibbe]

http://minimopar.knizefamily.net/electrical-links.html

Some other fuse links are ok with the 20amp blade fuses, but not that alternator feed. Remember how good it is at welding aluminum?

[BadAssPerformance]

Riiight

[Skibbe]

So the Code 46 was still causing my Power Loss light to be on, but I drove it to work today anyway. Took it out for lunch and the light is off now. So either I got a good charge on the battery on the half hour ride to work, or the PL light burnt out. Either way I think I'm ready to go racing.

[Skibbe]

I took some pictures, so I might as well post. These go along with Russ's MiniMopar write-up on how to replace a fusible link at the A1 splice.


If you're lucky, the link will have blown the insulation apart making it easy to find. Otherwise you have to do the tug test and see if the wire is still continuous in the link.



Rather than tear into the A1 splice, expose the feed just before the splice and tie in the new fusible link there. In this case I'm replacing the alternator feed link, a 12 ga fusible link, with fusible link wire from NAPA. Russ says to make the new link the same length as the old one, but by tying in on the other side of the splice it's going to be about 1" longer. If anything, this is extra protection, not less, as long as alternator load doesn't trip the link early. (So far so good for me).


I use a cable tie to help hold the new wire in place for soldering. Make sure the joint is clean and the solder is bright and shiny when done.


Tie in the other end of the fuse link to the 8ga alternator feed. You can cut the old link flush with the A1 splice insulation.


Cover the splices with electrical tape and friction tape. Go racing.