Need wiring help

I went and checked, i do in fact have a thermostat. after seeing it i remembered putting it in when i put new plugs in. i thought i did, then convinced myself that it was the car i put it in.

 

You could dunk it in a pan of boiling water to see if it opens. It should be closed at room temperature.

Could take a while for the engine to get up to operating temperature, if it's just sitting and idling in very cold weather.

 

thats what im hoping. ill just jump in it and drive around a while and see how it does.....

then i woke up..

ill check it again once i get the alternator right, put a couple extra gallons of fuel and let it idle half the day if i have to.

 

I found a post from 5 years ago that sounds simple enough for the alt. wiring.

stud on back of alt. to starter solenoid terminal with constant power.

Ignore position one on top (white wire in my pic)

Position 2 (red wire) goes to Ign. terminal on ignition switch. so it pushes power to it when ignition is on.
if for some reason there is backfeed install diode to stop it.

like a relay?
i think i got this, someone confirm for me? or kill my dreams and say im wrong lol.

yall have been a great help, especially you mr Walt Couch. come down and ill buy you a beer or dew or whatever floats your battleship.

 

That's not quite correct on alt hook-up. Your alt is a 10SI type. The Bat term on alt should have at least a 10ga. wire (RED) going to the hot battery cable on starter solenoid. Then make you a short jumper wire and connect it to term #2 and then down to Bat term (output) on back of alt. Same term as wire going to start solenoid (HOT). The next wire term #1 will go to your Gen/Alt bulb in dash (if you have one). If you are using a Volt meter, then you will need a wire from Ign hot when "ON" going to a 10 ohm resistor that then connects to term #1. This is to excite the internal regulator for the Alt. That should fix you up.

 

well walt, as of right this second i have complete understanding. i pray that does not change. looks like i basicly had term 1 and 2 mixed up. maybe. if i think too much i might confuse myself again. i can just get a ten ohm resistor from the 'shack right? 10 ohm 12V?

 

For resistors, voltage is not so much of a concern as power rating.

Your typical resistors will have a voltage rating way higher than any voltages you're likely to need, ie 600V, 2.5kV or such.

The power rating is important because it determines how much current the resistor can flow without burning up. For example, a 1/4W resistor is rated for 0.25/12 = 21 mA (P=IV). Pick a power rating that is appropriate for the current needed to excite the alternator. I'm not sure what that current will be - the wiring diagram shows the resistor but does not give a value. If I could not figure out what size to use, I would just pick the largest 10R resistor that I could find and use it. Won't hurt anything to go too large, as long as the resistance value is correct.

 

The Prestolight b-i-d ignition system did not have a resistor wire or external ballast resistor. If you turn the Prestolight box over and look underneath, you will see the ballast resistor is built right into the ECU. This is different than the points or the Duraspark systems used later. It doesn't matter if the ballast resistor is before the coil or after it in an electrical sense.

Don't put a ballast resistor on a Prestolight as you would just be doubling up on the resistors cutting your current way down.

The 10 Ohm resistor shown for the alternator is really just a resistance wire cut to a length that will give you 10 ohms and then spliced onto a normal wire. It's tought to get a wattage ratting on a wire so as timgr said. Get the biggest one you can find. I've actually used a tail light on one of my jeep one winter. It also served as a handy engine compartment light. You can actually pick up resistance wire at NAPA.
If you were to unwrap that harness you will actually see the red wire from the output post connected to the red wire going to the plug and the white wire spliced into the other wire coming from the other splice. Surprised they didn't use duct tape.


As for the diagram. it's the way the Haynes manual shows it. I'll have to check the 74 FSM to see if it's points or Prest or both. sometimes they will only list the latest schematic of a particular year.

By the way, that's a good start on rewiring your jeep but I think you should but it inside a box as the wheel spray will make quick work of all your neat connections. Maybe a nice tupperware box with holes cut into it so you can snap the top off quickly. It will keep the water/mud spray off the components.

 

Or better yet, use one of these and its completely waterproof.

 

If you simply run the white wire (brown wire in a stock GM harness) as the groundwire to a idiot light on your dash, and then keyed power to the other side of the light then you will have a "charge" light just like all the GM cars that run a 10 si alt. The bulb will be enough of a resistor and everything will work.

 

Went to radio shack and picked up a 10 watt 10 ohm wire wrapped resistor. that was the biggest they had. wired it up from terminal one to igition switch. term 2 jumped to battery post on back of alt. large gauge wire from batt. post to constant on starter solonoid.

i did not want to run it through an idiot light because i am simplifying the wiring and dash (cant you tell how simple its become???) when all is said and done all there is gonna be on the dash are the gauges, toggle switches for lights, heater, aux lights, and whatever else im forgetting.

i will be putting a waterproof box around the fuse block. trying to figure out if i want to just put a rubbermaid thing around it, or if i could find a small flat ammo can to put it in. ill just have to look around and see what strikes my fancy.

i ran the jeep for 45 min or so today. found out that why it was not heating up and running like crap was the carb. it was locked in "choke" mode. after forcing it open it ran almost good. gonna rebuild carb this weekend, get a friend with a timing light over here and set the timing. from what ive heard on here, trying to decipher between engines... 8-10 degrees advance is what i want for a 258 with a 4bbl carb at sea level right? or at least is a good place to start?

if everything stays the same then my engine wiring is DONE!!!! all thats left is simple stuff that does not require resistors and proper voltage and all that good stuff.

problem i ran across today was that my oil pressure is reading nothing. not when reved, or anything. hoping its just a bad gauge.

i might get to drive this thing for the first time ever before too long. i hope

 

No guarantee that you have good oil pressure, but with no OP you would hear a terrible lifter clatter. Hydraulic lifters simply do not work with zero OP.

BTW the sending unit seems to be a common failure.

 

That's what I was thinking. Gauge staying at less than 5 and motor running almost good makes me think gauge or sending unit.
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after spending a rediculous amount of time in the freezing weather i finally managed to get the heater/switch wired up correctly. took a lot of time with a meter and thinking to figure it all out, rewired the switch to the...springy things...after time and patience its all straight.

i did find out that if you find that the smallest spring is broken it is a real pain to get put back into place.

all thats left is

fixing drivers seat bracket
recovering seats (autozone special for right now)
wiring headlights, tail lights and turn signals
parking brake
rebuilding carb
set timing
finish installing soft top (hardware is already in place)
putting dash back in
new gauges


wow that sounds like a lot more now than it did a few min ago.

wish me luck

 

Not wiring questions, but wanted to see what yall are running as far as idle speed and timing. I have a 75 with a 258, offenhouser intake, 600 cfm holly 4bbl. pretty close to sea level.
Also which do I set first idle or timing? I'm supposed to plug up the vacuum line into the distributor for setting the timing right? Sorry for the stupid questions but this will be my first experience with timing.
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You'll get better answers if you start a new thread.

 

Another quick wiring question. why does my dimmer switch have 4 wires? not sure what they are all for. one power in, two wires get power on one click, one wire gets power on the next.

unless i find something out, im gonna run one power in, the one by itself as low beam, and the two together as high beam and high beam dash light.

Ideas?

 

Correct, the two that get power, one for the high beams the other to the indicator on the dash.

 

SWEET!!! I got it right!!!go me