my all day 105 amp alt install diode ??

[breezy]

Well it took me all day to get the alt. on but it's finished. I tried the resistor and it wouldn't charge, so I left it out. Has anyone else had this problem and did you hook it up without it. Will it be ok? I also got the cover on to hide the computer wires and relays. Had to do a little triming but fits nice now. What do you guys think? You can see my wire from alt. to starter coming out the bottom of the cover. Behind the cover is a two post junction box from a s-10.

[Sport/Truck]

I think it looks really clean....

[breezy]

Thanks that's what I like to hear. I'm not the fastest guy, but I like to measure 4 times then once more before cutting.
Anybody got input on the diode problem. I put a 470 ohm resistor in and it would not charge at all. I got that resistance from a GM diagram on a 86 vette, which is what the alt. is from.
How do you check the wire for resistance? I read it somewhere but can't find it now.

[dwcsr]

Did you use a diode or a resistor?. Diodes is one way electrical valve it has a + and - side if you put it in backwards it will stop the flow in the direction you may need. Resistors are 2 way so it doesn't matter which way they go in.

You can get a voltage drop from a diode but in this case you want a resistor. I use 75 ohm resistors for a CS130 conversion.

Snap a picture of the back of the ALT so we can see the wires.

[breezy]

Sorry bout that DW. I used a resistor. 470k-ohm 1/2 watt 5% tolerance. Cant really get a pick of the back now. I can tell you blue wire to L wire in CS harness. Red wire to Bat stud on alt. Looped wires in voltage regulator plug. It charges now but without a resistor. Putting out 13.4 at idle at 40 amps.GM shows 510 ohm resister so I figured I be good with the one I got. I wonder if my new pigtail has resistance built in. I burned up my multi meter so I'll have to check the wire for resistance tommorow.It may be ok it seems to be working correctly. I drove to town and back and it worked great. I just want to be safe.

[dwcsr]

They do make them with and without the resistor so maybe you have one with a resistor already in it. If your getting 13.4 I'd leave it alone.

[Husker]

I did this to my Jeep CJ 5 and used a diode and it works fine. I also plan on doing this to my 70 GMC.
Ron

[breezy]

I just got a replacement plug from O'reilly. I have read if the voltage is not showing resistance it will cook alt. in a few seconds. Did not say anything on package about resistance. Hopefully I'll find out more tommorow. I'm not driving anymore until I can verify voltage at L terminal or check resistance from battery cable thru harness to L terminal.

[dwcsr]

Originally Posted by breezy

I just got a replacement plug from O'reilly. I have read if the voltage is not showing resistance it will cook alt. in a few seconds. Did not say anything on package about resistance. Hopefully I'll find out more tommorow. I'm not driving anymore until I can verify voltage at L terminal or check resistance from battery cable thru harness to L terminal.

If you just got a plug then I would check to make sure

[screamin_c10]

Originally Posted by breezy

I put a 470 ohm resistor in and it would not charge at all.....I used a resistor. 470k-ohm 1/2 watt 5% tolerance....GM shows 510 ohm resister so I figured I be good with the one I got....

There is a HUGE difference between a 470k ohm resistor and a 470 ohm resistor. There is little difference between a 470 ohm and 510 ohm. If GM wants the 510 ohm and you are indeed using a 470,000 (470k) ohm resistor then you will have issues.

[breezy]

Yeah I figured that out today while pondering over this. Doh I failed to see the K and relized I was way off. The one I have now is 10K at1/2 watt. It charges now but I'm not convinced it's correct yet. I can't find the correct one at radio shack.

[VetteVet]

Here is all you need. http://temp.corvetteforum.net/c3/zma...ternator02.htm

The adapter for the SI alternator you won't need because you still have the regulator wiring. If you're in love with the external regulator you can use the resistor between the two bolts providing you change it to any resistor above 30 ohms and below 500 ohms. 10,000 ohms is way too much and will drop the voltage too much to turn on the alternator. If it was me I would ditch the regulator and wire the alternator like the link above.

You can also wire the red wire and the white wire together at the regulator and use the white wire as a voltage sensor to the S terminal on the alternator. Then all you need is a 10 gauge red wire from the back of the alternator to the battery or starter terminal.

[breezy]

I'm not in love with it, it just still looks original. It is charging with the 10k ohm resistor. Not sure how but it is working. Voltage is 12.3 I think.

[VetteVet]

Don't think me critical I was just wondering why you wanted to keep the regulator. It certainly is your call. Most of the guys like to get rid of it and clean up the engine compartment. That's a great place to mount the relays for the headlight conversion.

I didn't answer your question about the 10 ohms on the brown wire to the regulator, so here goes. The factory trucks had either a charging light or an ammeter and the light was a 10 ohm resistance. If the ammeter was used then a 10 ohm resistance was built into the brown wire. There may have been a resistor wired in with the light also to give 10 ohms to the regulator in case the idiot light burned out. I have diagrams that show that. Here is one without it.


And here is one with the resistor.


Now here is why I posted back. Your last post said you were getting 12.3 volts out of the alternator at idle. Most everyone gets 14.5 volts and the reason is because 12.3 isn't enough to keep the battery charged fully and run all the accessories too. I would replace the 10K ohm resistor you have in the regulator with a 75 ohm 3 watt and see what your alternator output is.

[breezy]

Where can I get one. Radio shack says they have nothing in the 3 watt range.I can't post the diagram from work but it shows a 510 ohm resistor in the wire from GM. Also I have checked the voltage with and without a 470 ohm resistor and it was the same. I'm not sure 75 ohms is going to be any different? I'm going to install the 470 and run it so it has a resistor. but I really don't see the relevance of it. I did notice when I had it wired direct I was putting a little over 14 volts out at idle. But when reving engine up it didn't go up much just stayed around 14 or so.

[Husker]

Try this write up it will work for a GM truck. It gives part #'s and several different diagrams. You can buy resistor wire at NAPA.
Ron
http://www.jeepforum.com/forum/f8/ne...estion-763216/