1970 Cuda 440 orig non a/c car


OK, I just upgraded my alternator to a later style Nippondenso from a 1990 Dodge Truck (Picture attached).

It was a pretty simple install, and when I fired the car up, the lights were nice and bright, and the volt meter jumped up to 18V+ when I revved the motor a bit, then "pop", one of the headlights blew out. Well, I chalked it up as a bad bulb, and kept revving, then "pop", there goes the other lamp. I turned on the high-beams, and you guessed it, "pop" and now those are both out.

I didn't change the wiring at all, as I've been told this is a direct boltin/swap as far as the wiring goes. I did however run an additional heavy gauge wire from the alternator output to the starter relay stud.

What would have caused this? This is a 90 amp external regulated alternator. The reason for this swap was because I'm running an electric fan, A/C, and needed more juice, now I have too much!!

sounds like a no regulator issue?

The regulator is there, and wired in. I traced the field wire on the back of the alternator to the voltage regulator. Like I said, I kept the wiring stock. The VR is fairly new, probably been on there for about a year.

It sounds like a regulator issue.
Normally the charging system tops out at about 14.5 max, and that's on a discharged battery.
Very much above that and you start frying things.

18 volts is waaaay to much for the bulbs to handle.

regulator issue.

you didn't say why you thought it was a direct wiring swap, what regulator do you have? single field or dual field?

WHAT CAR IS IT, and how did you wire it in?

1970 Cuda 440

All articles/archives I read on this swap stated it's a direct swap. Dual Field Regulator.

http://www.allpar.com/history/mopar/electrical.html

yep it is for that. sounds like it blew out or something happened to your wiring when you spliced in the new plug for the alt.

I would replace the vr or have it tested, and back track your splices.

Thanks! I actually have an extra VR on hand, and I will try that first after double checking the wiring.

I was thinking it was the wire I added from the alternator stud to the starter relay as it bypasses the VR... Would you guys recommend that I keep this wire there, or no need for it? I did add a fusible link to it.

Thanks again!

that doesn't by pass the vr. That is a feed line to charge the battery. will help keep the strain off your old wiring. I would leave it. And I would get rid of the fusible link.

on my exsuperbee I had similar problem I replace the vr alternator it didn't do any good finally had enough so I took it to my job mechanic he found a wire going into the bulk head into the dash was burn! he replace the wire had no more problem...

Thanks everyone for the suggestions. I suspect it is a wiring issue, as the volts have always been a bit erratic even with the old alternator.

I'll be tackling it this weekend and will post the results, should this happen to anyone else.

Well, I've tried the obvious. I grounded the Voltage Regulator on to the block and cleaned up all the connections, Including the body ground. I even added a ground from the alternator body to the frame. Any other suggestions? The car fires right up and runs great, but when I rev the gas, it pegs out at 18 volts.

Let me just say this now, wiring is not my thing , so I may have missed something obvious... It's a 440 Cuda with Electronic Ignition, after-market A/C, autometer gauges (no ammeter). My voltage always fluctuated, but didn't become a problem before I put this late model alternator in it...

As always, I appreciate you guys. You always seem to get me out of a rut

What BigTerry said makes sense. I would try the battery drain test to see if there's a miniscule short that's enough to drag the voltage down on the cabin side of the harness, but not enough to fry the fusible link or wiring to the bulkhead connector. I don't have my FSM handy, but I would disconnect the pos cable of the battery. Hook up a multi-meter that can handle at least a little current, between the the pos terminal of the battery and the cable. If it registers a current, there is a leak (or battery drain, if you prefer) somewhere. If the key is off, the leak would be somewhere between the battery and the ignition switch, as the reference voltage for the ignition (and VR) comes from the switch, IIRC.

Another way might be to simply disconnect VR with the iginition in "run", but the engine not running. See if you get battery voltage. If not, the column harness or dash harness may be the culprit. Work back with the voltmeter to see what's what.

I may be off-base here, so I hope others can chime in. Good luck with it.
-Marq

After rereading my post, I realized that you didn't mention anything about the battery going dead overnight or over a week, so that's probably not the problem. The probelm probably lies somewhere between the ignition switch and the VR. I'd start tracing voltage back on the blue wire through the bulkhead to the ignition switch.

Sorry for the earlier red herring...

I'll add to that something that happened to me a few years back. the clip that holds my balast to the firewall (68 charger) didn't exactly fit the new ballast I had installed as part of my MP electronic ignition conversion kit. One day on a turn, it moved and the terminal on the ballast made contact with the metal clip...fried that wire all the way back to the engine compartment side of the bulkhead connector. I replaced it and tightened the clamp.

I was stupid not to check the wiring inside the car. years later while crawling under there for some other reason, I saw that the wire had actually fried itself on the passenger compartment side of the bulkhead connector. this thing was cooked!

the moral of the story is that you could have some fughazy wiring up under the dash and not even know it.

I did the denso alt swap a long time ago..2002. definitely keep the extra charge wire you added between the alt and starter relay. I used a 4 gauge wire, what did you use? mine is a 135 amp unit of an 02 ram van...even though yours is a 90amp, i'd still use a big wire. check your VR plug too. if it's the triangular shaped one, it could have some issue inside of it that you would never see.

This weekend I actually replaced the VR and Plug, and double checked the wiring. Not a single difference. I'm at a loss here...

Maybe it's time to take it in to have another pair of eyes look at it. I just hate to have other people touching my ride. Argh.

I took some time tonight to look into this again. After pulling off all the tape and wire looms, I traced each wire back to it's origin. After looking closely at one of the field wires, it was pinned between the alternator and head. I loosened the alternator, and there it was; bare wire was rubbing against the block.

I'm making progress, and now the volts are pretty steady, and max out at about 15.5 when I peg the gas. Should I be concerned? This still seems a bit high.

Thanks again everyone!

14.7V should be max, from what I've heard.
Sounds like you still have an issue with the sense lead to the VR.