First off, I would like to thank Curtis for taking a look at my truck today. We did all the usual test, and all were good. Injectors sounded good and there were no codes. The only thing that got his attention was my voltage. It was .5 lower then his and I have the dual alternator setup. Is there a way to check individual alternators for voltage output. Also, whats the wiring like on a duel set up, are they chained? I ordered a new 160amp alternator from Quick Start Automotive Electric, but now I find out I have two Can I order a second, and will it bolt up like the top one? Also got to ride in his truck and WOW, its fast!

 

They're controlled by the PCM. IIRC, the lower alt is only energized when the upper one cant keep up, like when the glow plugs are on after startup or when you're running a power hungry electrical device. The part number for the lower alt is different, so I'd guess that they have different mounts. Check out the large power wire that hooks the alts to the batts (black w/orange stripe i think). The half volt could be from a bad connection, corroded wire, or maype even a bad fuseable link (they run two 14 awg links in parallel IIRC).

 

I'm guessing that since there is some switching inline, that voltage difference could be from that added circuitry. But it could simply be differences in component tolerances, too. I wouldn't worry about .5V myself.

 

Andrew it was good to meet you too. Definitely a nice truck you have there.

When looking at the truck and testing systems out, there was a code that popped up referring to an issue with the dual alternator setup. His voltage is running at 13.7v, which isn't necessarily bad or anything (mine runs at 14.1 with just a single), but we wanted to know how to test the dual alternators to find out if there is a problem. I wasn't sure of the test procedure, other than unbolting both of them and running over to the nearest auto parts store, but that would be a pain with 2 alternators. It would be nice to catch a potential problem early, if there is one.

If anyone has any suggestions, post'em up.

 

I would thing a ford dealer could test this, but it's probably going to be expensive. Twags6, thanks that helps.

 

Side note, just went to the ford dealer on lunch, changed my fuel filter back the ford one. No leaks, yes! When I got back into the parking lot at work, I decided to see if I had any blow by, before there was not white smoke, but now there is a small puff puff. what would cause that to change, could it possibly be the oil change that caused it?

 

Was the code P1105, P1106, P1107 or P1108? Those are the only ones I see for a dual alt set up. I can email the test procedures if you PM me your e-mail address.

Austin

 

sent, thanks

 

No sweat. I sent the info and procedures for all four codes. Hopefully that will cover you for whatever code was popping up.

Austin

 

Austin it was the P1105 IIRC

 

I sent 87 F-150 I6 the procedures for P1105, 1106, 1107 & 1108 which is for all four dual alternator DTC's.

If you want me to e-mail them to you also, just pm me with your e-mail and I'd be happy to shoot them out to you.

Austin

 

Cool, it would be handy info that I don't have yet. PM on it's way.

 

You could individually unhook the charge lead (or the control lead for that matter) of each alternator. When one is off, see what battery voltage is, then reverse, then check voltage again. If in both cases, the voltage is in the 13.5 range, you should be good. Neither alternator should be maxed out on a DD truck, just idleing in the driveway, just after starting. Unless you left the radio on a while. Unhooking the control wires, is not always the safest, sometimes it can lead to a broken plug. (happend to me once, on our early 99) If in either case, your voltage drops down to 12.7ish or below 13 volts, theres a good chance one of your alternators has failed. The difference between your two alternators voltage, could be a very simple thing. The charge voltage varies with temperature. The regulators in our alternators, compensate for temperature. If you have a real volt meter, and watch it throughout the year, you would notice this. Winter for me the voltage can be as high as 14.7 . Summer it usually runs in the 13.5-13.8 range. Reason they do this, is because when batteries are cold, it takes more voltage, to make the battery have the same capacity, as it would at a warmer temperature. If you look at battery discharge/charging charts, they usually have a rating for both warmer, and colder temperatures. hope this helps some.

 

No sweat. Sent 'em out a few minutes ago. If there's a problem with opening the attached files, just let me know.

Austin

 

That's good info, thanks.