Help with Dizzy and Starter wiring...

[hardwaycooke]

ok...everything was running fine and I pulled the engine for the 383 update. I have a couple questions about some wires I found in the process.

Pic 1 with the larger redish wire and the open ended yellow wire are the 2 wires I pulled from the starter, not including the battery cable.

Yes I do have a HEI setup so why were there 2 wires connected.??? Can I cap off one?

Pic 2 is a green wire with a female end and the other, larger orange wire was cut--these were just hanging loose

any ideas??

[Ironangel]

The green wire may be the water temp gauge wire from a head mounted sending unit.
Your question is a bit unclear on the first pic. Some HEI distributors got their 12 volt power from the hot side of solenoid while the other wire was the keyed switch for the starter...

[hardwaycooke]

Originally Posted by Ironangel

The green wire may be the water temp gauge wire from a head mounted sending unit.
Your question is a bit unclear on the first pic. Some HEI distributors got their 12 volt power from the hot side of solenoid while the other wire was the keyed switch for the starter...

ok...I didnt show the ign and tach wires...I know where they go. The 2 wires in pic 1 both came off the starter. I thought I only had 1 wire needed.

Also my green temp wire is not in pic. I have that one labeled and set aside. Thats another green wire.

[Bigdav160]

Perhaps I'm looking at the picture wrong but I don't think it is correct.

The "S" terminal should be the small one on the right. It is usually purple and comes from the neutral safety switch.

The yellow is connected to the other small terminal. It's purpose is to supply battery voltage to the ignition coil bypassing the resistor wire during cranking. It is not necessary with a HEI.

[Ironangel]

You never know what previous owners and mechanics may have done under them hoods...Or what option combinations were installed when the truck was new. As far as I know is, (which aint much) the only green wire in the engine compartment is for the water temp sender. All other green wires are lighting circuitry...Some 72's had "TCS" systems that integrated the carbs and transmissions to control the idle but I dont have a diagram for that...Can you trace that wire to a block in the firewall? Heres a link to various diagrams, some with HEI and some with the standard coil & dizzy... https://www.google.com/search?q=GM+w...11%3B428%3B681

[hardwaycooke]

Both of pic 1 wires were on the original starter WITH the HEI and the HEI has a wire from the ignition. I guess thats ok, it didnt affect anything. Should I just cap the yellow wire off?

The other 2 wires were just hanging in the air above me when I was looking up removing the starter. I will try to follow them sometime this week when I get into it.

Thanks

[Ironangel]

Thats a quick pic offline...As long as you follow the "S" and use the switched "purple wire" on the "S" terminal, your good...Heres one with the old school coil and dizzy...I think GM used a resister wire rather than a ballast resister but the diagram is good.

[hardwaycooke]

yeah its the 2 loose lines concerning me.

Would the yellow line still being hooked up not affect anything??

[VetteVet]

The yellow wire would be hot with the key on if it was still connected to the ignition switch. It was tied into the resistance wire and the R terminal on the starter to provide a full 12 volts to the ignition coil during cranking. It is not needed with the HEI distributor.

[engineer_gregh]

When I switched to HEI, I capped off the yellow wire and no longer used it. No need for 12V from the switch just hanging out:-)

[kenn]

hello my 72 has a sending unit on both sides of the block in the heads, I think one is for a light but I'm not sure about that.
Both wires are green and have that thick insulation on them.

[hardwaycooke]

[QUOTE=kenn;6788454]hello my 72 has a sending unit on both sides of the block in the heads, I think one is for a light but I'm not sure about that.
Both wires are green and have that thick insulation on them.[/QUOT

i dont understand why it would be for a light..hmmm.

Anybody??

gonna test them all this weekend..

[kenn]

I am just assuming that its for a warning light?
I have had the truck for 3 years, done some engine work and know there are 2 sending units. I figure one is gauge and one is light. Now I'm going to have to check that out also.

[knomadd]

It's really hard to say what a previous owner/mechanic might have done. You should really trace the wires in question back to where they terminate to find out what it's for. Many people have cut wires and used them for other items than intended for by the vehicle manufacturer. Relying on what it "should be for" is risky.

[72MARIO]

When I converted my trucks to hei. I followed the yellow wire to the fuse block and replaced it with a 10 gauge red wire to power the hei. The green wire is for temp gauge.