Need wiring help

First off i have read EVERY thread that has anything to do with this and cannot figure it out. im sure its very simple and im being dense, but what can you do.

i am simply wiring up a new (generic) ignition switch on my 75 cj5. i have the starter wire and battery wire handled. its the IGNITION terminal im having problems with. where does it go? does it go directly to the coil? does it go to the box on the fender? im not sure what ignition system i have. i dont know anything.

but i know how to take pictures.

does it go directly to the red wire here? if not where does the red wire go?


Does it go on the starter solenoid anywhere?


Does it go to the red wire here? and what is this thing? is it the ballast thing ive read about? is it the ignition box?

i really need some help with this peoples.

 

The "little box" in the last pic is your voltage regulator.


In the first pic, what wire are you talking about. The one on the negative side of the coil? If so that wire would go to your voltage regulator.

Here is the electrical schematic.

http://civilianjeep.info/Strenk/Electrical/74-75Merged.jpg


Bottom left is where to look.

 

Nope - it's a '75 and it has the Prestolite electronic ignition. That's the electronic control unit (ECU) for the ignition.


Not sure where civlinianjeep.info got that diagram, but it's wrong for a '74. A '74 will have points ignition. Looks ok for a '75. You can see the ECU on the diagram, connected to the distributor. A '75 with an inline 6 will have a Delco alternator, with an internal regulator.

 

duplicate

 

Hmmm. I stand corrected.

Got to love a Haynes manual.

 

The only way I can help you is by using the diagram posted by Jokenring. Looking at the diagram, you have two ignition wires. One is labeled 12E it's a 12 gauge Red wire and the other is labeled 75 (these are on the diagram) and the 75 wire is Red with a tracer and also 12 gauge. Those should have been the only two ign wires you removed from your old ign plug. Does this seem right to you.

 

I think if you look at the solenoid on the fender you will see the two small terminals marked as "S" for the starter wire from the key switch, and "I" for the ignition wire from the switch. I just finished wiring my '73 and without the schematics in front of me, I think that's the way it was laid out. The letters on the solenoid are usually molded on the case right above the terminal post.

 

as far as what i removed i yanked everything all at once. there is nothing left. The PO had messed everything up so badly nothing was right at all anymore.
i see wire 75, but lose it once it gets to the fuse box.
it looks like red wire with tracer come from ECU, splices up, and one of the splices ends up on the positive of the coil. does that mean i can just hook up red wire to positive and be done as far as ignition goes? looks like green from ecu is the only wire on the negative.
i had to pick up a new coil today because old one was so corroded that was not connecting to wire anymore. guy up there said it would be easier to use the ford coil he gave me because it has the internal regulator and i would go straight from the ignition to the positive on the coil. is that right?

also said i would hook up the electric fuel pump to the ignition on the switch too. right?wrong? should i just hook up a few relays for all the stuff running through the poor ignition switch, or can it handle all of it?

so to sum up what i think im hearing (which could be wrong) ...
Green wire goes From ECU to NEG terminal on coil. thats ALL for neg.

Ignition wire goes straight from switch to POS.
Red wire from ECU also goes to POS terminal on Coil. That is all for POS.

Fuel Pump power goes to IGN terminal of ignition switch.

 

You cannot hook ign wire to positive on coil (ref wire 12E) because you should have an ignition resistant wire built in and that would cause a voltage drop backfeeding your fuse panel and cause problems. The tie point for wire 12E feeds the fuse block. Therefore you should connect wire 12E to your generic sw that is hot in run and crank position. Make sure your generic switch has this capability. The 75 Red W/tr wire, which also feeds other parts of your fuse block can connect to the SW terminal that is hot in "RUN" position only. Your SWitch (generic) has to be able to supply power to the start solenoid in crank and "RUN" during crank position and then drop the crank power when the switch is dropped to the "RUN" position. This is because your start solenoid does not incorporate a start bypass. Your coil should not have an internal resistor as the vehicle wiring has or should have the built in special resistant wire going to the coil + terminal. If you are running a tach then more wires will have to be connected. Let me know. HTH. Walt.

 

First, your sig says "fiberglass tub." NB the jeep will not start or run unless the fender is grounded. If you have a fiberglass fender, you must run separate ground wires to both the starter solenoid and the ECU.

Second, I would not put a lot of time and effort into reviving the Prestolite parts. This system is very troublesome and uses a triggering method (Hall effect) that has been abandoned by the automotive industry.

Since you seem like an electrical newbie, the simplest route would be to discard the Prestolite distributor and module and fall back to a points ignition. Then use a generic wiring diagram to connect the ignition.

Most people would replace the Prestolite stuff with a different type of electronic ignition. The GM HEI is popular, and simple to wire up, but I'm not a big fan. I would use a '78 or '79 Jeep distributor (Autolite "Duraspark") with one of several different and compatible modules.

 

tim,

it appears in the last photo, of the ECU, that there are in fact ground wires running from the ECU and the solenoid to the frame.


as you noted, most ditch the prestolite b-i-d unit. i did. makes a world of difference in performance, especially at low rpm.

wally

 

I think one of the main problems im having with the 12E thing is i've also changed the fuse box to a new blade fuse box. i am trying to wire really simply, fuse box, igniton switch, toggles and relays, like a boat or a drag car. so im not running the wires the same. So when 12e splices out i lose it. i just need to know what directly to hook the ignition up to so it all works. there has to be a simple answer. the fuse box is one (big) wire in, all the rest of the wires out. so the power to the box is coming directly from the battery. I'm trying to use the KISS method. but it does not seem to be working for me.
The fellow at the parts store gave me an ignition coil for a ford and said that its simpler because of the internal regulator.
im so confused. maybe i just need to go to sleep and figure more out in the morning.

It was running before when i had the positive off the coil, the fuel pump, and the red wire out of the ecu just pressed to the positive terminal of the battery. so i know it runs. just had to change out the coil because it was too corroded for the distributor wire to hook to it.

im so confused:?. maybe i just need to go to sleep and figure more out in the morning.

 

Yall aint done, i know someone has the magic "this is where it goes" POOF!! answer

 

Sorry but there is no simple answer because you no longer have a simple jeep..You now have other unknown parts. Possibly wrong ign sw, known wrong coil, possibly wrong fuse box.. If you can tell me if you still have the original special resistant wire? If you no longer have it, then the ford coil with internal resistor (not regulator) will work with your system. The Red wire off your ECU unit should connect to the + (pos)

term of the coil. Your elect fuel pump should connect to the ign switch via relay or fuse, (size depends on motor draw). How we doing so far?

Sorry-- my bad.. You don't have the special resistive wire so disregard that part.

 

The 75 wire and the 12E wire are still important to your existing wire system (eng compartment) so both wires will connect to your new fuse box that will be hot when key is on. Your Ign sw must be capable of having a terminal that is hot in (ON) and during the crank position, but separate terminals. Because your vehicle has elect ign, it must have power during the cranking procedure. Point type systems get their power from the starter solenoid during crank. Your solenoid will not provide this power that is required. HTH

 

no resitive wire. no problem hooking red wire from ecu to pos terminal.

take meter and make sure power is going to ignition terminal when on "crank" if it is not i can just take a one way diode and make that happen no problem.

12e is (in my usage) just the "ignition terminal" from switch as far as i can tell.
75 looks like it goes through the resistor that i dont need anymore since the coil already has it.

im gonna run a relay off the ignition switch for the "ignition" terminal so i dont pull too hard through the switch. 12e is gonna go through relay and to positive. fuel pump is gonna go through same relay.

i dont know about 75 though. 75 seems to be the last part of this puzzle at the moment.

sound like we are on the right track?

 

The 75 wire was ign feed to a tie point (B) which supplied power thru fuses to your 1=Back-up lights 2= ign feed to 10 ohm resistor at alt plug-in for low rpm charge start and 3= one other fuse (unreadable) top left on your old fuse block.

 

After freezing my BUTT OFF for several hours today (i live in SOUTH Carolina, windchill of 28 at the warmest is Unaccptable) i now have a jeep that i can turn the key and crank up, turn off the key and it shuts off. very nice.
like i said, its cold today, but after 15-20 min running it still did not hit 140 degrees (according to the gauge), heater coil was warm, but not hot, and radiator water was cold. Thermostat never opened. is this a sign of a problem, or just cold?

here is my new fuse box and relays and such. i will of course clean up and tighten wires.


now i need to figure out how to wire this altenator (sp) there are too many things goin on with it.


The wires off the bottom left are going to the constant power on the starter solenoid. the top wires are all spliced together and go nowhere. if i put the meter on the top wires, using them for the ground i get like 10 volts or so. is it as simple as attaching them as a ground and it charging right?

another thing....someone tell me what this is...unless its antifreeze from a cracked block or something. then i dont want to know. oil is still clean, little thin looking though.

 

Sounds to me like you do not have a thermostat. The 'stat starts off closed, and opens when you reach temperature.

Looks to me like the factory Delco alternator. You can follow the wiring diagram linked to above to connect it. Can't tell you off the top of my head how to wire it, but someone here should be able to.

Clean the valve cover and see if the green stuff comes back. Looks to me like it's oil dripping from the filler cap. Could be condensation - hard to tell unless the engine get up to temp and runs long enough to evaporate any condensation in the crankcase. Look for water in the oil and oil in the coolant, and do a compression check if you worry.

 

at first i thought "no way i dont have a thermostat." then i thought more and more about all the really stupid stuff that PO did...imma go check in a min. it would not surprise me at ALL to find out that it does not have one.