Alternator Problem - Stuck in Panama City!

Hi all - this is my first post but I have been a lurker for over a year and you guys have helped me fix all sorts of problems while building my ambulance into my home on wheels. Thanks a bunch!

Now I have a problem that I cannot find a solution for in the forum archives. I am traveling to South America and currently in Panama. My alternator charges sometimes, and then stops charging at other times. Since it turns on and off, I originally thought it was a loose wire/connection somewhere, but everything under the hood is solid and clean. I have not follwed the 3 wires that go thru to the cab (red/grn, grn/red, and blk) to look for connection issues yet.

I do not want to remove the alternator and take it to a shop here until I am fairly confident that the alternator or internal regulater is the problem. The electrical shops here can be spotty.

History - about 7 months ago my voltage regulator went out (alt constantly put out 18 volts). I replaced the alternator with a Wilson (160 amp) reman from Oreillys and all has worked great up until now. Same alternator.


Electrical System - 2 starter batteries, and 3 house batteries separated by a Blue Seas automatic isolation relay. 400 watt solar panels connected to the house battery bank. All of the house appliances are connected to the house battery bank. Starter batteries are connected to the alternator and all the standard van cab components.

The Problem - sometimes the alternator charges and sometimes it does not. Sometimes I can run it for an hour and all different rpms and get it nice and hot, and everything seems to work fine. Sometimes it will just stop charging and the "AMP" light comes on. Sometimes i will drive it for an hour with no problems and then stop for an hour, and when I start it back up, no charge and light is on. Someti
mes it fixes itself and other times it does not. Next morning, all works.

I have been checking voltages on the wires/terminals when it is charging and not, and at different rpms and loads. One thing that i recently saw is that the alternator is putting out 14.3 volts at idle, and drops to 14.2 when I turn on the hi- idle switch. it has normally output 13.3 or so at idle and jumps to 14.2 to 14.4 at hi-idle... wierd.

The alternator has 3 wires - large red output connected to starter batteries and starter, Red/grnstripe connected to a threaded stud post that goes into cab, and white/blkstripe connected to a flat spade terminal that goes to what I believe is the AMP warning light relay screwed onto the front grill left of radiator. (see pic below). The relay has a black wire and a green/redstripe coming to it from the cab. I can hear the relay switching on and off as the alternator starts and stops charging. Sometimes it clicks back and forth pretty fast for a few seconds.



The wires on the alternator measure as follows:
Big output wire - 13.3 to 14.4 depending on idle and battery charge state.
Red/grn wire - always about 0.2 to 0.3 volts less that the big red wire
Wht/blk wire - 6.2 to 7.0 volts when charging, drops,to 0.2 to 0.3 when not charging

AMP light relay wire measurements:
grn/red wire - 13.2 to 14 volts when alt is charging and drops to 0.03 volts when it stops charging.
wht/blk wire - same as above

i also measured the voltages at the alternator wires under different loads' and yesterday, as I added more load (increasing fan speed, lights, radio), the alt output at idle progressively dropped from 13.3 to 12.8, and the red/grn wire dropeed accordingly staying about .3 volts less. the white/ blk wire dropped from 6.6 to 6.4 volts.

The alternator stopped charging at this point so I could not test it at hi idle last night.

This mornng the alt was charging again, so I tested it again and...

At idle, with increasing loads, the alt output started at 14.0 to 14.6 volts (fluctuating like as if was AC), then dropped progressively down to 13.3 volts as I added loads.

At hi-idle, the alt output dropped below the output at low idle??? i have not seen it do this before. As I added loads, the alt output stayed almost constant at 14.2 to 14.3 volts.

Before, if I revved the motor I could see the volt guage in dash increase with rpms, but this morning it stays the same or even sometimes drops a little as I rev the motor.

The only components I see in the syastem are the alternator w/ internal voltage regulator, AMP light relay, AMP light in dash (which seems to work correctly), the ignition switch, and ground.

So my question is, are these symptoms telling me my alternator or voltage regulator are bad, or there another issue, or is there something more I need to test?

Your help would be very much appreciated as I am stuck here in Panama until i get this fixed.

Does the alternator have a warranty?
I would go to the parts store and have them test it, with it on the truck.
Definitely sounds like the alternator to me, with the varying voltage.
If it was a wiring problem, I would expect it to keep normal voltages, but put out nothing at times.

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jaspe - I bought the alt in California. I am now in Panama trying to get to Colombia to continue my venture to South America. Returns are not an option. Neither are Oreillys or other franchise parts stores. Electrical shops here are sketchy. I will take it to a shop once I have a good idea that it is defintitely an alternator issue. If I take it to a shop, they will have to rebuild it with who knows what parts. this alternator is not available in Panama and doubt a rebuild kits is available either. I am hoping that an electrical guru can look at my post and tell me definitively that my alternator or regulator is the culprit, then at least I can go the the shop and tell them what i want them to do, instead of relying on them to mis diagnose it or just make something up to save face. That is sort of the the way it is here. Some shops are great, others are not, and I have no idea which kind I will end up at. Thanks for your help.

I hate to rain on your parade but Wilson stuff is sketchy, I refuse to use them unless that is all thats available. I see you have a leece neville, That is the older style, I would look for the new model prestolite or delco that will bolt up correctly. Try a truck supply. Prestolite now owns leece neville. You may have a brush sticking or a diode opening intermittently , I had that exact alt on my 4x4 and now have a 3g, that model leece neville is not reliable because of the crappy parts available for rebuild.

He must have missed the south america part.

I am in no way an expert on alternators but what I will say is that it almost sounds like something is getting hot and breaking down. You say after you shut it off for a while it seems to work again. That to me says electronic component failure. In this case I would guess that the regulator is suspect. Again the voltage dropping when the RPMs go up, says to me the regulator is doing something goofy. I don't know if that is at all helpful to you but at least you are getting bumped up to the top of the pile again. Hopefully somebody who has messed with that particular alternator will chime in. I think FarmerFrank may have mentioned putting that alternator on something he has a while back.

Good luck and safe travels.

Welcome to the forum. It does sound like the alternater is suspect from what you posted. If I was reading what you posted.. then you have 3 batteries in the rig?/ If so you have plenty of reserve power to probably drive several thousand miles on whats in the battery set. All you really need is about 7 volts to open the fuel shutoff solenoid in the injection pump. Just don't shut down the engine and waste power trying to restart it. Don't run with any electrical items running like heater fan or ac compressor. Also do you have 2 alternators on the ambulance. If so change some wires and run off the one thats working. As to the idle voltage it looks fine. If the alternator checks out fine I suggest you look at the circut that tells the dash gauge your charging. Might also be the dash gauge gone bad too. Many years ago my 89 charging system appeared to fail on the freeways. The battery lite would come on telling me I was not charging. I checked the alternator thru a mom and pop shop. No problems. Well it took 2 years of this happening on anf off till one night it happened after I dropped my gooseneck off at the stable. So I opened the hood as the engine was running and looked things over with a flashlite. I moved the dash charge wire on the alternator and saw a slight electrical flash. Much closer look showed the copper wire had broken between the insulation crimp and the connector crimp for the copper wire strands. It was like magic how it was cleanly broken off the lug. Had it not been dark I would never have found this. May have been a vibration issue. These diesels do vibrate at different pitches when running. This is why we have the olives in the fuel lines to and from the filter and the vibration clamps on the injector lines. Sounds like you are on a great trip down south. Be careful and don't drink the water...

First of all welcome to OB and sounds like a hell of a cool trip to me.

Ok two completely different parts in one system and both could be suspect.

How about locating a NEWER 3G 160 or even 130 AMP internally regulated Alt and install it? Most 90's Fords would have one.

Just a thought.

Why oh why on earth would you do a trip like this without some essential and basic spare parts I would never know.
However for a trip like the one you are on I'd have ONE hell of a box of spare parts, belts, IP, replacement Injector line...flexy emergency one, GP's, belts, hoses, lift pump, PS pump, Alt, AC by pass pulley if AC is there...Ya spare parts for travel like this to third world country essential..oh some wheel bearings for front and rear too. and U joints..

JM2CW

thanks for the help. sounds like i need a rebuild. I will take a trip into town tomorrow to try to find an electric shop who can either rebuild my alternator/regulator, or possibly find me a new one somewhere.

I like the 3G upgrade idea, however I am not too sure how feasible it is to accomplish here in panama. We shall see. I wonder if they call them 3G here too?

Would anyone happen to know a part number for the 3G that I would need for my rig?

Or maybe (longshot) a vehicle that was sold in latin america that uses it?

Maybe I can source an alternator and install kit in the states and have it shipped here to panama. Does anyone have a link to a source for those items either?

Thanks again.

id consider a more known gm alt like the older internally regulated ones from the 70's and 80's.7127 used to be the number.

anybody can fix or repair one of those.ive done many myself. theres also one with a bigger body,more amps. easy to wire too. just run a wire from the B+ to one of the connections and the field gets power when the key is on.

I can't see how your alternator mounts for sure. There are several options for a 3G alternator. Several 90's ford cars had them. The later 90's ford pickups had them. Honestly I'm a little surprised your van doesn't have it because its a 93. Probably something to do with the ambulance package. The 3g i bought for my 91 is for a F700 actually. There seems to be a couple different mounting styles. I'm giving you these links just so you can have pictures to look at. I have no idea if these sellars are any good. This is for reference only.

This is the style that is most similar to the old 1 G alternators.

http://www.ebay.com/itm/FORD-3G-IR-...:1995|Model:F-350&hash=item27e2573388&vxp=mtr

Here is another style

http://www.ebay.com/itm/Brand-NEW-A...:1995|Model:F-350&hash=item3cd72a7878&vxp=mtr

Here is the plug for it.
http://www.ebay.com/itm/ALTERNATOR-...:1995|Model:F-350&hash=item4cfc604342&vxp=mtr

There is a good tech article on the conversion here on the forum. I haven't done my conversion yet so I'm not an expert on it but I have the parts I think I need.

Hope this helps you out.

Edit: BTW, there is a really good tech article taking you through all the different versions of this alternator floating around on the internet. I think it's on a bronco forum. Google will find it for you.

Go to a Fire or EMS station and ask where they take there vehicles for repair. They should have the knowledge or where they get there parts.

I would check all connections first. If there is a plug on the Alt, that is a suspect.

OK, I found a good electrical repair shop and they actually had the correct 3G 130 amp alt and the plug, so I bougt it and will domthe swap rigt now.

However, they did NOT have a175 amp fuseable link.

What will happen if I install the alternator without the fuseable link?

I am currently running a higher amp alternator (160 amp), and all has worked ok, so why do I need the fuseable link when I change alternators? Most of the conversion writeups i have read say I need to install this link... why does my ambulance not already have one? They were pretty thorough with the electrical system when they built this thing.

Thanks for your advice.

Fusible links are just insurance for the OEM's to make sure the vehicle doesn't burn down if something bad happens in a accident. If you are careful with your wiring and not let it rub on anything, you will be fine without one. Most all the older vehicles in the 60's and earlier never ran fusible links. You would hear about the occassional wire burning in two or a battery terminal melting off in a blob. That is what will usually happen.

In your case, move on without one is what I would do.

Tried,to do the swap, but the mounts will not fit without me building a bracket. Is that what normally needs to be done to retrofit one of these oni a 7.3l IDI in an E350 van?

Old bolt spacing is 8 1/8" (only uses left 2 mounts)
New bolt spacing is 8 1/2"

Old alt mounts do not exactly bisect the center of the alternator, therefore I have to rotate the new alt clockwise and it hits the inside curved part of the mounting bracket. I would need to build a small bracket to extent the upper mounting hole to the left so that the new alt pulley lines up with where the old alt pulley was.

Is this normal for this mod, or an I missing something, or is this mod not donemon vans?


(sorry pics are upside down)

One more issue on the 3g alternator swap. My old pulley is bigger that the biggest one They had for the new alt.

Old alt pully diameter 78mm (3 1/16")
New alt pulley diameter 67mm (2 5/8")
Crank shaft pulley dia 180mm (7 1/8")

So this will make my alternator turn faster, but since this alt was probably designed for a higher rpm gas engine and I am putting it on a diesel which will turn slower, is there any issues here? Or do diesels run bigger crank shaft pulleys?

Just did some quick calcs. I do not have a tach so I used a cruising rpm range of 1500-2200 ( not sure if correct).

At 1500-2200 engine rpms
Old alt turns at 3400 to 5100 rpms
New alt will turn at 4000 to 5900 rpms

The testing spec sheet that came with the 3G alt shows a testing range from 1600 - 6000 rpms, so I am assuming that i am still in the normal operating range for this new alternator using the smaller pulley. Is this logic correct?

I have an E4OD tranny.