voltage regulator

You cannot believe the level of off roading you do with a jeep thats alternator dosn't charge the battery. Add to that, the engine cuts out at intervals. I just got home from off roading for 10 hours. My jeep stalled out and wouldn't start so I had to ditch it, hide my tools, hike 5 miles in the dark, then spend 2 and a half hours trying to find it later. Got it home, thought we fixed it, took it back out. Well, it stalls out but the main problem is once it stalls, you can't start it due to the battery not charging off the alternator. Any tips on how to get it charging? 1974 CJ5 258. I think it might be the voltage regulator since it has 4 wires going to it and one is snipped, but I cannot find the wiring diagram anywhere. Suggestions? Any one have a good diagram that explains the charging system?

 

Had the same problem, most alternators don't put out many amps at idle and just off idle, and you probably have the 64 amp alternator, so during slow operation it's probably not putting out 15-20 amps, and if your running with lights, radio, and maybe spot lights, your using 30-40. Fixed it by going to a later model ONE Wire 97 amp model, easy to hook up and keeps you charged.

 

Same problem here on my 74, I found my wirring diagram in a Haynes repair manual. Chapter 10-16. I'm in the process now putting a 360 in my jeep and the motor came out of a full size Cherokee, I noticed it had a one wire set up. So now I have brackets. Good luck!

 

I just got done getting the externally regulated system on my '70 working. Which kind of the following 4-wire systems do you have?

 

The 74 alt's are pretty weak. Even mine at idle with no accessories on at all has the amp light dimly lit. Goes off after a quick rev but kinda lame anyhow.

 

The Motorcraft alternators were known to pop diodes. With only one-half of the rectifier working, the output will be very weak. We (at the Jeep dealer) used to fix them with new diodes, and I expect parts are still available, but it's probably cheaper today to buy a rebuilt replacement.

 

jayhawkclint, this is exactly what I was looking for!!! I couldn't find it anywhere. I have the one on the top. This should solve my problem. One more question tho, where does the white wire coming out of the top right of the voltage regulator go? Is that just a ground, considering it seems to lead nowhere? Or does it go to the battery? Thankyou so much, this should definitly solve my problem, now I just have to figure out why my jeep stalls all the time, but that it a different thread altogether

 

Actually I read in the jeep bible to always disconnect the leads to the battery before giving the battery a quick charge, or it will destroy your diodes. Well, I probably gave the battery 8 quick charges, with the leads still hooked up until I found this out. I couldn't figure out if the diodes you destroy are in the battery or not. The battery is toast, but thats to be assumed from getting a quick charge rather then a slow charge. Could I have destroyed the alternator which explains why my jeep stalls randomly? It sounds like its running out of gas everytime it stalls, so I figured it was either and auto chaoke problem or the carb needs to be rebuilt. What do you think?

 

Here is a post I made on another board. If you want to step up to a great 94 amp alternator.... with a little fabrication and extreamily simple wiring.

for 94amp (12SI) models, ask for an alternator for an ’84 Camaro, 305G engine, 94amp Alt

they called that a 3 wire alt. but I would have called it a 3 wire. has the single output and the two wires out the top. That would be the right type to get and easy to wire... only one of the two wires has to be used and can go right back to the output term as I recall?

94 amp factory alt should be pretty respectable.

so I did some further reading.... one wire and three wire alt is the same thing.... cept.... the one wire has a self exciting voltage regulator. A three wire needs excitement (so do I) to I belive term 2 on the regulator. This is also the voltage that the regulator works the alt to. So..... if you run that regulator wire to the ingnition you turn on excitement (is that redundant?) you get a more accurate voltage regulation to the battery as opposed to the one wire that is regulating voltage inside the alt which is going to be a higher voltage than the actual battery sees due to resistance....

so.... 12SI clean easy install and 94 amps....

 

Okay, here is from my experiences fixing my '70. It is a GM style, but from what I've read the principle operation is still similar. Kinda lengthy, but I swear this is not rocket science. Hope it helps:

(1) I highly recommend that you get yourself a multimeter that can read DC volts and DC current. I am not pitching any one meter or another, I own many, but the one I find myself using on my JEEP more often than not is a $40 unit from Sears that can measure volts, amps, ohms, even temperature (useful if you ever need to accurately diagnose cooling problems). I probably could not have fixed my system without a meter.

(2) I found while metering my alternator that it does not kick in until about 2500 or 3000 RPM (I don't have a tach, so can't say for sure). Once you rev the engine it will start charging, but not until then. I don't know why this is, but I have read before that there is a purpose for this. So, while it may be "cheesy", it seems to be normal. I found that even when my alt is charging, at idle I cannot run the vehicle off the alt alone if I have headlights/accesories on (i.e. I cannot start the vehicle, let it idle, disconnect the battery, and then turn on the headlights). The engine will shut down. My point here is that some, but not all, of your symptoms may be normal dead battery indications.

(3) From the sounds of your wiring, it seems that some previous owner may have tried shade tree repairs. The diagrams I posted were from my Painless wiring kit. Mine is a '70, so I can't say for certain, but Painless is saying that WHT #714 connected to your starter relay and its purpose was to energize your alt exciter. If this is true, then I think you need to somehow connect it to a +12vdc ignition source. This is where my source of frustration began.

(4) Once you get a new batt installed and the voltage regulator connected correctly, turn everything off. Make sure there is not a single light (even your AMP warning light), guage, ign coil, radio (if it has memory, then disconnect it entirely) that could possibly be drawing juice. With your multimeter in at least a 20A mode, connect it in series between the NEG batt post and the NEG batt cable. If everything is good, you should read zero. If something is not hooked up correctly, you will be reading some current. Now, if it is a small current, say <.05A, you may have just missed turning something off. If it is anywhere in the range of 2 to 5 amps, then there is the possibility that your alt exciter is being triggered even with the batt off. This will kill your batt and possibly cause your alt to malfunction. In my case, someone had connected an extra wire causing the alt to constantly see +12vdc.

(5) If #4 applies to you, reconnect the batt and probe around in the VDC mode to find stray voltage. You should only have +12vdc on the batt post of the alt. Also check the + side of the ign coil to make sure that isn't being triggered as well. The objective here is to get it to be activated by some kind of ign switch triggered wire, and nothing else. You might have to ask another AMC owner to help you with this part. Then proceed to #6.

(6) If #4 does not apply to you, connect the batt back up, then go get a buddy. Put your meter in VDC mode and measure the batt. You should get somewhere between 11.8 and 12.2 volts. Turn on the engine. Measure the voltage at idle. It may bump up a small amount. With your buddy well clear of moving parts, rev the engine to about 3000 RPM and measure the batt. Should be upwards of 13.8 volts, maybe even as high as 14.2. If it is over 14.4 max, you may have a bad regulator. I have heard that +15VDC is alt burnout range, but cannot verify this for sure. If it remains at ~12VDC, then either a) your alt exciter is not seeing juice and therefore not charging the batt so troubleshoot the regulator some more, or b) your alt is burnt out and needs to be rebuilt/replaced.

Beyond this, I'm not sure I could be much help since I have only experience with GM 3 wire and 1 wire systems. If you do go the replacement route, from experience I think the 1 wire system is over-rated. It is easier to install (although you will have to hack and stow some of your existing wiring), but beyond that there are no benefits. In fact, you are losing some of your benefits of having an AMP warning gauge. Also, you can get a high performance 3 wire alt for sometimes half the cost of a 1 wire.

 

Once again, thank you. this sounds excellent. last night I was going off roading but the jeep died right outside the trail so I re-thought it and headed home. It died two or three more times on the way home, which I restarted with a spare battery and jumper cables. Eventually i left the cables connected to my spare so I wouldn't have to keep getting out everytime it died. Didn't die any more, plus the headlights and horn started working again. I didn't know if this was a coincidence or not. Apparently you need a battery connected to keep the jeep from cutting out. I screwed up, but only because I was under the impression that the way to test and alternator is to start the vehicle, pull the battery lead and it should run forever if its a good alternator. I am very excited to realize that my problem was so simple. I need to wait a few days to fix this as I got very sick from being up over 24 hours getting my jeep out of the woods incombination with getting soaked with bacteria ridden, stagnent puddles. Thankyou so much, I will let you know how it went.