Got a link?

So you're saying that having constant power to the L terminal is not a problem?

Andrew

 

FYI we have schematics of most of the common alternator wiring methods on our site

http://www.painlessperformance.com/schematics

 

No. I believe the guy on yellow bullet was saying you don't have to connect to L terminal but I can't confirm that.

If your car is running you should be able to do some testing. If mine was running I'd do it.

 

But not AD244 or DR44G GM alternators and I'm not sure if the CS regulators are compatible.

 

In my 71 chevelle there is a resistance wire that use to go to the ign coil for pionts distributor. I think it was around 9 volts. Would that work to plug into L terminal on alt? That would be awesome

 

I don't know about 9v. You could try it though.

Andrew, I take back what I said about constant 12v to L. Even with the bulb, tha 12v is always being applied so the 12v output from your Dominator should be fine.

 

Thanks. I will see about trying to wire the S terminal to the fuse block. If I can do it cleanly, then I see a benefit by providing a feedback loop to the alternator, which presumably is the whole point of the voltage regulator...

Andrew

 

I'm kinda curious about this also... My cousin is getting ready to wire the alternator into his 38 Chevy w/ a 5.3. We were looking at his fiance's truck (I want to say it's right in the same era 02-04 w/ a 5.3), and the alternator connector plug on her truck only had one wire going to it. I thought that was weird. I'll have to look again, but I want to say it was a pink wire going to either the 2nd, or 3rd pin from the left it looking at the plug straight on from the back. I thought it was supposed to have at least 2 wires? I'll take a picture next time I go look at it.

 

Does this help at all?

 

To add to the confusion...
https://ls1tech.com/forums/conversio...tml?styleid=26

 

I wanted to close the loop on this from my end. I got the Dominator wiring in my Cougar all done and wanted to see if how I wired the L pin on the alternator would work. To recap, the L terminal is wired into an output on the Dominator. The Dominator has multiple user programmable inputs and outputs that can be configured for any number of uses.

Since there was consensus that the L terminal needs a switched + source with a resistor, I used the alternator pigtail sold by Holley that already has the resister installed. As stated I ran that wire to a connector in the Holley harness and programmed that pin to provide a switched 12 volt signal to the alternator whenever the RPM were above 250. So when the engine is off, or stalls, there is nothing going to pin L even with the ignition turned on.

I ran a big wire from the alternator output post to the battery side of the starter solenoid (Ford style). With the ignition switch in the RUN position I saw 12.4v, which is battery voltage. As soon as I started the engine, I had 14.7v output on my Holley digital dash. This is the voltage that the ECU is seeing and it is connected directly to the battery.

I am not going to mess with connecting the S terminal because I see no reason to complicate the wiring any more than necessary. With the alternator is putting out a steady 14.7v while the engine is running, I am happy.

Comments and questions are welcome.

Andrew

 

Does yours vary output as load changes?


This is a PM from 1989GTA:

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1989GTA
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Default Re: Alternator
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Originally Posted by SSSTANG#1
Which alt do you have? So you ran 12v to the S (sense) terminal? What is the output now?

Thanks, Steve


I have the DR44G that originally had the two pin regulator. It was not working out with the default 13.8 volt charging. I bought a 4 pin regulator for it and installed that. The alternator is charging just fine.

Yes I ran S wire to the 12V from where the ECM picks up its voltage. The voltage varies from around 14.5 when first started up and slowly goes down to around 14 volts after awhile. Allen
1989GTA is offline Forward Message Reply With Quote

 

It doesn't seem to. Just a solid 14.7 output, just like my GTO, which also has one wire going to the L terminal. I can easily run a wire from the S terminal to where the alternator output wire connects to the hot side of the starter solenoid.

Maybe I should do that? This is essentially where the ECU gets power.

Andrew

 

So, I read this website thoroughly:

http://www.pirate4x4.com/tech/billav.../Part2/#wiring

In it, it says that the S terminal on the alternator should go to a bus bar that serves as the main point of power distribution. On the website they encourage the use of a bus bar.

I really don't have a power bus bar, but I do have most of my major power circuits going directly to the battery. So I figured the best place to attach the S terminal was on the hot side of the starter solenoid, which is directly connected to the + post on the battery with a very short cable.

I had some pins that work with the metripac connector on the alternator, so I made a wire that goes from the S terminal and goes directly to the hot side of the starter solenoid. The wiring isn't complete, but I wanted to see what would happen as a proof of concept.

I started the engine and once it started, the voltage at the battery was right around 14.4 volts. This was a little less than the 14.7 that I noted previously. I didn't run the engine long because I don't have the cooling system working, so I don't know what the ultimate effects will be. Presumably, as more demand is placed on the battery (headlights, coolant fan) the voltage will be adjusted to meet demand.

I plan on permanently wiring the S terminal as I described and will see what happens. This is a learning experience for me and I am eager to learn from it.

Andrew

 

Good deal Andrew. I have a through the firewall terminal with 1/0 from the battery to the starter. That is where I have the fuse box supply wire tied in along with power for a relay board so that is my bus bar. I ran the wire from the S terminal to the bus bar. Now I just need an engine in the car to test it.

 

Just a little more info to throw in here. This evening I fired up the car with the laptop hooked to the Holley Dominator. This was I was able to turn the fan on full blast to see what happens to the voltage. On my GTO that only uses the L terminal, when the fan kicks on, there is a significant voltage drop, from the normal 14.7v down to 13.5v. If the headlights are on, it's even worse.

I started the engine and it immediately showed 14.2v. Turned on high beams (these are wired through relays with power coming directly from the battery) voltage dropped to 14v. Kicked the fan on to full speed (I have PWM fan control so I can vary the speed) and voltage dropped to 13.7v. I just let it run like that for a few minutes and as it kept running the voltage started to go back up to around 14v.

With the headlights (say 20 amps), fan (32 amps), fuel pump (10 amps), ECU (maybe 20?), that a total of about 80 amp load. Good thing I got the 130 amp alternator.

I am eager to read what others find when they wire the alternator for both the L and S terminals.

Andrew

 

Just here to add to the conversation that helped me with my alternator wiring.

I wired both the S and L terminals and had the exact same experience. With the high beams, Taurus fans and radio all on. Voltage dropped to ~13.7v, but ended up slowly building back up to ~14v. This is all through a stock ECU (if it matters). Much better than the default 13.8v of the 2-pin I had previously.

 

Making an old school idiot light work with LS alternator is simple.

Wire in your idiot light lead to pin L (brown wire) on your alternator in PARALLEL with the brow wire. In short, just splice it into the brown wire. Done. Works.

Do not need to attach sensor wire to positive terminal. Not necessary to fix this issue.
Why parallel instead of in series like above posts say? So alternator is still getting power when bulb goes out. DO NOT NEED to splice in resistor to accomplish the same thing unless you have no brown wire plugged into L terminal to begin with. DO NOT NEED resistor if you just run another switched 12 power source and have two wires going to it instead of one. ONLY need resistor if you want to use the one idiot light wire to both deliver 12 volts AND make idiot light work.

I have read through many posts. A lot of bla bla bla, and no real solutions. And the posts that actually stumble on something that works, do a lot more work than necessary. Like resistors and S terminals. None of it is necessary to make the idiot light work in your old school car on a LS alternator.

your welcome.

 

How did you remove the original external regulator wiring out of the equation? I'm working on a 68 Tempest and paired up Blue/Red (470 ohm resistor) and White/Brown with a DR44G. Can't find the right combo for the light to work.

 

I did a 69 lemans a while back. On this model, the power feed for the lights came directly from the regulator. No regulator, no lights. You need to find the 12v constant power wire going into the light switch and wire another 12 source to it after you cut out the regulator. On other GM models, that feed comes off of one of the pins on the horn relay. If yours goes to the horn relay, it will come from the regulator into the horn relay and again, you will need to feed that wire with 12v constant. If you still have the factory fuse panel, there are 2 bare spade pins in the center of the fuses. One is 12v constant for accessories like a power top the other is keyed on power for other add on accessories. You can plug your power feed for your lights in there and it will be fused.

The other wires coming into and out of the regulator you do not need. You can either de-wire them or just cut them out and terminate the ends. The only one you need is the main power going into the regulator tied back into your fuse panel constant power feed. The rest do something close to nothing. With a single wire alternator, which already has a regulator built in, you only need...1....wire going to the battery. 8awg minimum. If you still have the rest of the factory wiring, you already have power coming off of the starter motor wires feeding into your regulator, which now needs to be bypassed to your fuse panel.

You can also leave the regulator in if the wiring is sound to begin with. Not going to hurt anything. GM regulators are fairly reliable. Dodge regulators need to be cut out. They were problematic when they were new. In fact, if you are thinking of restoring a Dodge made before late eighties, consider an after market harness. Did a 86 ramcharger a while back. What a mess. Regulators put out anywhere between 13 to 16 volts, brand new. And i do not mean a range, i mean this one put out 13 volts, that one put out 16 volts and so forth. No rime or reason. just hit or miss. Lights were bright or dim depending on which regulator you had at any given moment. Turn signals worked or didn't, fast or slow, wipers were slow mo or good all depending on the stupid regulator. Lights on, wipers going AND you want to turn? ROFL, better hope you have the 15 or 16v one. The 13 volt was going to make you choose what you wanted based on priorities at the moment. Want a stereo with an amp? Better wire it directly to the battery and not via the factory harness.

About the factory "gen" light. On the LS alternator there is a 4 pin plug of which only one pin is used for the computer. The pin in the center right next to the CPU wire, brown i believe, can be wired directly to the "gen" warning light. That plug is hot when the alternator is putting out 12 volts or more and grounds when it is not. IE your "gen" light will go on when you turn the key on and go out when you start the motor. It will also go on when the alternator stops putting out voltage. That one wire is all you need to hook up to make it work. Just run a wire from that pin to the back of your instrument panel.

If you have not addressed the speedometer yet for the 68, this is what i did to mine. I took a factory tail section from a 700r4 with mechanical speedo and put it on the back of a 4L60, direct bolt on. Can use the factory speedo. You can then buy a converter that plugs into the trany and then into your factory cable and has an electronic 2 wire sensor for the LS cpu. I wanted to keep the factory gauges. And i did.