CS144, Big 3, Big Battery Done. One Question

Just finished my charging system upgrade (seems to be pretty common around here lately), everything seems fine. I do have one question about the harness that connects the GM alternator to the Tacoma's wiring.

I bought a plug and play harness from ebay so I would not have to cut the truck's wiring. It is as shown in the attached images (sorry can't figure out how to insert picture directly into post).

The problem is that while researching, I found a good alternator article (http://www.pirate4x4.com/tech/billavista/Wiring/Part2/) which explains the connections on the GM cs144 and the difference between (P L F S) and (P L I S) I know P is not used, L is lamp and is required, S is sense and is required, the issue is F/I wire depending on which alternator is used.

Mine is an F (field monitor), and is connected as shown in the simple diagram attached. Much of my research started with blackdawg's build (thanks Monte for the wealth of info) and it looks like his is connected as well, but I don't know if his is a F or an I.

If anyone is familiar with GM alternators or has done the swap and had no problems please let me know. I just don't want to burn out a voltage regulator when I could have just snipped that wire and have been fine.

Sorry if this is confusing, kind of new to the whole forum thing. Thanks in advance for any help you guys can give.

First (3) attachments are of the harness I bought. Next one is a simple diagram found on expedition portal through a link from blackdawg's build thread (wiring section)

 

bump for info

 

I connected all three wires as one of the link in my build(which I believe is now sadly gone as the site died) explained very well what the cs144 wires are and the Toyota ones.

Basically you only need two like the last diagram you posted. I only hooked up the three due to the one article and he said it can help a bit with efficiency but no real proof with that.

That said...mine works totally fine with all three wired up the way I did it. But should also work fine with just the two.


So assuming you little connector you bought is wired with two wires to the stock harness and you need to run the bigger wire to the + post of the alternator..then you'll be good

 

Thanks for the response, Monte. I am thankful for anyone who wants to help out with an opinion, but since your build was my guide for this project I was kind of looking for your results.

I performed a couple of checks on the charging system today, and went for a nice long test drive. Everything seems to be working great. The charge indicator light comes on with the key on, engine off and goes off when I start the engine - good. The battery voltage was at 12.59v KOEO, and 15.23v KOER, this seemed a little high, but after a good long drive I checked again and KOER voltage was down to 14.65v and KOEO was up to 13.23v, so that all seems good. I do have a few follow up questions, though.

First: I used the same circuit breaker and main battery to alternator wiring as you, but my charge indicator (battery) light does not come on when I trip the breaker. Does yours, should it?

Second: Do you know where the original main ground from the battery goes? I ran new grounds to both the frame and the engine, so I should be fully grounded, but because I was unsure of where the original ground went I left it hooked up as well (I am running a dual purpose marine battery, so I have standard automotive terminals and 5/16" threaded, so there is plenty of room for connections). Being that the new battery is bigger, the original wire is stretched pretty tight, and I have quite a few wires snaking around my battery, so getting rid of a redundant wire would be nice.

Other than that the project seems like a success, once again thanks for the help.

 

i have read that the voltage will sometimes peak at 15v at startup. Goes away tho and never an issue. If it stay that high though..could have issues.

The battery indicator won't come on unless the battery is pretty much near death too.

the bigger ground wire that came off the battery is for the starter i believe. You'll need to keep it.

don't forget to run a ground wire to the body as well.

 

Right on. Thanks, Monte. I tend to be overly obsessive compulsive when it comes to stuff like this (which is why it is nice to have very detailed build threads to refer to). After driving it a bit and watching the output voltages, I'm convinced that all is well.

Sometime in the future I plan on tracing down that main ground and either eliminating or replacing it, I'll let everyone know what I find, but it may be a while.

As far as the body ground, I'm still using all the factory ground connections except one. The main battery ground (factory) had a small (14-18ga ?) spliced in at the battery that is only about 3" long. The PO had it connected to the inner edge of the fender with a self tapping sheet metal screw. It wont reach the fender anymore so I plan on just using some of my leftover 4ga wire to ground chassis-engine-body, but not tying it to my battery. I already have quite a few connections at the battery, and if I'm grounded from battery to engine and from battery to chassis, and have engine, chassis and body all grounded together, I think I should have all bases covered.

Once again thanks for the advice.