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Hello, I am new owner of 1978 c3. I have couple of question. I am really sorry for my english
Little details on engine, I have edelbrock carb and edelbrock manifold, with accel coil1. Thermostat housing have another hole for vacuum. Where should I connect it to?
2. This green wire it is supposed to be connected where?
3. This red wire, also...
Under this red wire there are vacuum hoses that are also cut in half.
Not sure the purpose of the thermostat housing fitting unless another form of reading the water temps was hooked there...it is not vacuum. With the opening I would think coolant would leak through the hole. Cap that fitting/plug it or replace thermo housing with no port.
Last edited by panther-19; Jan 27, 2021 at 10:36 AM.
Wow.....you have some issues going on there.....somebody has murdered your wiring at the Alt. The red wire use to go to the alt, right there at the two prong plug.......now they have it going to a black wire that goes ????? Find out where that goes......see what they did.....this is the alt field positive wire. I believe on a C3 it goes all the way back to the battery.
I do not know where the green wire goes but use this diagram: http://repairs.willcoxcorvette.com/w...e-this-one.png
Get a free diagram from member "Papadana".......you will have one within hours.
The thing on the water housing is not a vacuum port....it is the rest of a broken vacuum switch. The misc. vacuum lines under the alt wiring could be and go anywhere.
You need a LOT more info and have a lot to do here to get it back to good. It can be done. Go to the Wilcox site from the link above and see if he has a vacuum diagram for the 78 too. Without these diagrams....fixing all of this will be close to impossible.
As stated above...the stamp is for a Goodwrench 350....still sold to this day. Not a bad thing. A 2015 stamp date means the engine is fairly current.
Jebby
Last edited by Jebbysan; Jan 27, 2021 at 10:57 AM.
Wow.....you have some issues going on there.....somebody has murdered your wiring at the Alt. The red wire use to go to the alt, right there at the two prong plug.......now they have it going to a black wire that goes ????? Find out where that goes......see what they did.....this is the alt field positive wire. I believe on a C3 it goes all the way back to the battery.
I do not know where the green wire goes but use this diagram: http://repairs.willcoxcorvette.com/w...e-this-one.png
Get a free diagram from member "Papadana".......you will have one within hours.
The thing on the water housing is not a vacuum port....it is the rest of a broken vacuum switch. The misc. vacuum lines under the alt wiring could be and go anywhere.
You need a LOT more info and have a lot to do here to get it back to good. It can be done. Go to the Wilcox site from the link above and see if he has a vacuum diagram for the 78 too. Without these diagrams....fixing all of this will be close to impossible.
As stated above...the stamp is for a Goodwrench 350....still sold to this day. Not a bad thing. A 2015 stamp date means the engine is fairly current.
Jebby
"Not a bad thing. A 2015 stamp date means the engine is fairly current."
Not sure how you came up with a 2015 year for the block as that 0715 is the month and day of the build. The year would be on the rear of the block case.
"Not a bad thing. A 2015 stamp date means the engine is fairly current."
Not sure how you came up with a 2015 year for the block as that 0715 is the month and day of the build. The year would be on the rear of the block case.
Your assumption is incorrect any GM suffix code the last 4 digits were always month and then day of the month. The casting date was on the rear of the block on the flange to the transmission and cast into the block not stamped.
Thank you very much for fast response and your answers. This is very helpful.
I will take a look on that wiring on alt. Thanks.
Yes, its a project, but not my first. I am very happy for this purchase, c3 was on my wish list for a very long time now.
I was trying to find this guy who sold it in Texas to Europe, but no luck. I wanted a little bit more info about this c3.. But ok, I will get to know her slowly :P
What do you think about this setup then: this engine goodwrench 350, edelbrock manifold, edelbrock carb, and accel coil?
Is this ok, or should I go to original setup?
OK, I have read this topic, thank you.
What do you guys thinks, have in mind this current setup edelbrock etc, should I buy thermostat housing without holes, or should I look for this thermal switches?
So, I have managed to check the wires out.
The Green wire from the first post is actually blue and is for hood alarm. Ok. Easy part was done.
And then there is alternator wiring.
Red wire that is connected with black wire goes in the car with another wire from electric choke.
In the car
Divided again in two red wires, one was plugged in, the other one I dont know, it just fell out.
OK, so what should I do now?
Should I connect alternator as it was in original state, so the red wire from engine harness goes to alt, without connecting with black wire that goes in fuses?
How should I connect electric choke then?
The red wire from the alt was re-routed to the fuse box, probably because the original wire stopped having voltage......it should work as they routed it but it is terrible. This car needs an engine wiring harness......it is too much to try to explain how to repair the existing harness here. Someone has murdered the harness.......
You also need to print out a large wiring schematic for the car.
So, I have managed to check the wires out.
The Green wire from the first post is actually blue and is for hood alarm. Ok. Easy part was done.
And then there is alternator wiring.
Red wire that is connected with black wire goes in the car with another wire from electric choke.
In the car
Divided again in two red wires, one was plugged in, the other one I dont know, it just fell out.
OK, so what should I do now?
Should I connect alternator as it was in original state, so the red wire from engine harness goes to alt, without connecting with black wire that goes in fuses?
How should I connect electric choke then?
Thank you and kind regards
Mihela
Do you have dropbox could send you wiring diagram?
I will take a look why red wire stopped having voltage. I would try to make it work with this harness. It is only couple of wires
For electric choke is it ok that is plugged in Lps.? What Lps. stands for?
Should I place fuse in inst. lps. ?
Last edited by Mihela Starkel; Jan 28, 2021 at 04:33 PM.
Red wire that is connected with black wire goes in the car with another wire from electric choke.
In the car
Divided again in two red wires, one was plugged in, the other one I dont know, it just fell out. OK, so what should I do now?
This Red Jumper wire makes no sense to me at all.
Even "IF" there was a fuse between Circuit #44 (Right side of fuse holder) and Circuit #8 (Left side of fuse holder) of INST. LPS. fuse block there would be "NO" power to the LPS socket unless the headlight switch was 1.turned 100% counter clockwise, 2.pulled to park light position, or 3.Pulled to headlight position.
In the White 4 cavity plastic housing just right of the fuse panel the Pink/Black stripe wire is a switched wire.
The closest place for switched power is the yellow wire plugged into the wiper motor for your carburetor choke.
Here is a link from Willcox Corvette for the 1978 Corvette Electrical Troubleshooting Manual...
Best Electrical drawings out there. LINK:https://drive.google.com/file/d/0B28...JrTURuMGs/view
Thank You Mr. Willcox!
Last edited by bmotojoe; Jan 29, 2021 at 08:14 AM.
Reason: Removed Line 4 OP identified cut wire.
And then there is alternator wiring.
Red wire that is connected with black wire goes in the car with another wire from electric choke.
On pages 4 & 5 of the troubleshooting manual you will see the field winding forum member Jebbysan is talking about.
It could be that fusible link "A" near starter solenoid is burnt and that's why the Black wire was spliced in?
I'm with Jebbysan, along with the engine harness the starter harness would also be on my list.
Last edited by bmotojoe; Jan 28, 2021 at 10:38 PM.
C3 troubleshoot
