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-   -   Not a new member but just got a 75! (https://www.corvetteforum.com/forums/c3-tech-performance/4247603-not-a-new-member-but-just-got-a-75-a.html)

dzzman 03-02-2019 10:08 AM

Not a new member but just got a 75!
 
hey all! so i just scooped up a 1975 stingray. might be in over my head a little bit. never really took on a project quite like this before, and ive always had problems diagnosing fuel issues. its pretty rough. no interior, dash parts were in a box,not running, steering wheel is flopping around, body is in good shape, (seller stated it had no rust haha), a/c car, j code engine. quadrajet carb. i gave 2 grand for it and it came with all new drilled slotted rotors, 4 piston calipers, all new brake lines, and master cylinder. a few other cosmetic things as well, but i bought the parts pretty much got the car for free lol!! so far ive got a new alternator and got it hooked up yesterday. got her crankin over but def sounds like its not gettin fuel to the carb. im not too experienced with carbs and all the lines and such, as all my previous vettes have been fuel injected. im not really finding any diagrams thats helping me out and i havent really got to lookin around at any of the lines as my time is rather restricted right now. any help would be greatly appreciated or if i have to create a new thread i can do that too. thanks everyone!

Vetteman Jack 03-02-2019 11:52 AM

Moved over to C3 Tech.

derekderek 03-02-2019 04:02 PM

no interior? you would almost need a parts car for the interior. here is a sample central jersey. he wants 2200. not worth 1K. Body beat. frame rot. no hood over non-running smallblock. but inter looks decent. https://cnj.craigslist.org/cto/d/tre...830652462.html

Greg 03-02-2019 06:22 PM

Sounds like a fun project.
How 'bout some pics?

dzzman 03-04-2019 08:10 PM

new jersey an awfully far drive from southern indiana

dzzman 03-04-2019 08:11 PM

ill try n get some next couple days or so

kossuth 03-05-2019 12:10 AM


Originally Posted by dzzman (Post 1598973667)
hey all! so i just scooped up a 1975 stingray. might be in over my head a little bit. never really took on a project quite like this before, and ive always had problems diagnosing fuel issues. its pretty rough. no interior, dash parts were in a box,not running, steering wheel is flopping around, body is in good shape, (seller stated it had no rust haha), a/c car, j code engine. quadrajet carb. i gave 2 grand for it and it came with all new drilled slotted rotors, 4 piston calipers, all new brake lines, and master cylinder. a few other cosmetic things as well, but i bought the parts pretty much got the car for free lol!! so far ive got a new alternator and got it hooked up yesterday. got her crankin over but def sounds like its not gettin fuel to the carb. im not too experienced with carbs and all the lines and such, as all my previous vettes have been fuel injected. im not really finding any diagrams thats helping me out and i havent really got to lookin around at any of the lines as my time is rather restricted right now. any help would be greatly appreciated or if i have to create a new thread i can do that too. thanks everyone!

First and foremost you don't 100% know what you have but here is what you need to get it running. Fuel, Spark, and compression.

I would do a simple compression test on the motor first. I would pull all 8 plugs, put a charger on the battery, open the throttle all the way and check the compression on each cylinder. Should have at least 110 psi if not more in each cylinder. Each cylinder should be within 10% of each other but don't worry about that for now. Rings sometimes gum up from sitting and you'll get weird compression readings so I wouldn't get excited over readings if they are all over the place. You just want to make sure you're making something for compression. We want to make sure you don't have something like a jumped timing chain or something like that. Your local auto parts store should have a rental you can use or it's cheap enough to purchase

Next thing I would do is make sure you have spark on all of the plugs. That's pretty easy to do. Either pull the plug out of the cylinder you're testing or have a spare plug handy and roll it over looking for strong blue spark. You need a strong blue spark. If the spark is yellowish that would indicate an issue where you aren't getting the voltage over to that cylinder to arch it off properly. If you aren't getting good spark could be a host of things. Cap, rotor, coil, plug wires, bad ignition switch etc.

Lastly if you have decent compression and spark I would give it a shot of carb cleaner or brake cleaner down the carb and see if it pops over. I'm not a fan of using ether. If it pops over see if you can balance and it get it going. Once you have some engine speed it's alot easier for the fuel pump to start pumping. Being it has sat I'm sure the carb is bone dry. It might be ok and just take some work to get going or something in the fuel system could be shot.

If you get it firing off but can't keep it running I would start with testing the fuel pump. Make sure the fuel inlet in the carb is getting about 5 psi of fuel pressure. Not sure if this is a rentable tool but I would check.

Could be ignition timing but I would look at everything else first before I started into looking at the timing of the motor.

As for your question about a fuel line diagram. I did some looking and good luck. Honestly the fuel system on these cars is pretty damn simple. You have your tank with the sending unit with the gauge and such. You have two lines from the tank to the fuel pump on the engine. An inlet line and what is called a vent line. These would connect to the fuel pump which is bolted to the passenger side of the motor and driven off the camshaft. There is lastly a fuel line from the pump that goes up to the carb. Any pressure regulation is typically done by the pump if the car is setup just like OE.

derekderek 03-05-2019 06:02 PM

carb and brake cleaner is lousy gas. some these days is non-flammable. put a couple teaspoons of gas in carb.

dzzman 03-09-2019 05:02 PM

Some pics and update
 
Heres some pics of the 75
https://cimg2.ibsrv.net/gimg/www.cor...f6abfc7ba4.jpg
https://cimg9.ibsrv.net/gimg/www.cor...35aaec9d74.jpg
https://cimg4.ibsrv.net/gimg/www.cor...a23582c918.jpg
https://cimg3.ibsrv.net/gimg/www.cor...a39efbea62.jpg
https://cimg3.ibsrv.net/gimg/www.cor...1f1b950380.jpg
https://cimg4.ibsrv.net/gimg/www.cor...0cb67288d5.jpg
https://cimg9.ibsrv.net/gimg/www.cor...c4598668f6.jpg
https://cimg6.ibsrv.net/gimg/www.cor...debc9f289f.jpg
https://cimg1.ibsrv.net/gimg/www.cor...9554dac018.jpg
https://cimg0.ibsrv.net/gimg/www.cor...95f5cfd93a.jpg
https://cimg6.ibsrv.net/gimg/www.cor...19de99a8d8.jpg
https://cimg6.ibsrv.net/gimg/www.cor...3587feba90.jpg

dzzman 03-09-2019 05:07 PM

Update
 
So far ive tried to put a little gas in the carb. Not firing. Doesnt even sound like its want to start. I take number 8 spark plug and there is no spark when i turn the key. Was gonna change plug wires, but looks like a pain in the ass, im prob not gonna get to that today. I just got done switching distributor caps, on the old one the button was nearly flat and theres some corrosion on the metal contacts. Im getting voltage to the single red wire of 9.2v. Should next step be replacing ignition module? Coil? Or??

gmcman52 03-09-2019 06:35 PM

Nice to see another 75 on this site, you have your work cut out for you hope you have deep pockets from what I see in your pic's.
my own 75 was in a lot better shape and it still cost me a ton of cash. but hey what else are we to do leave it for or kids?
Good luck and keep us posted.

CA-Legal-Vette 03-09-2019 09:58 PM


Originally Posted by dzzman (Post 1599017483)
So far ive tried to put a little gas in the carb. Not firing. Doesnt even sound like its want to start. I take number 8 spark plug and there is no spark when i turn the key. Was gonna change plug wires, but looks like a pain in the ass, im prob not gonna get to that today. I just got done switching distributor caps, on the old one the button was nearly flat and theres some corrosion on the metal contacts. Im getting voltage to the single red wire of 9.2v. Should next step be replacing ignition module? Coil? Or??

Which single red wire? The one to the coil in the distributor cap?

corvetteronw 03-09-2019 11:01 PM

Start watching the You Tube videos made by The Corvette Ben. He works out of his Texas home garage and makes some pretty good C3 videos. Get yourself a C3 catalog from www.corvettecentral .com and start pricing parts. Hopefully you can find some of them used here or find a good supplier of used parts to make things less expensive.
I think that many have said to budget 3 times what you think you will spend and quadruple the time to finish the project.

dzzman 03-10-2019 05:07 PM


Originally Posted by CA-Legal-Vette (Post 1599018898)
Which single red wire? The one to the coil in the distributor cap?

Yes theres 3 plug ins. 1 is single red wire connector, 1 single brown wire connector ,the other is 3 wires in one connector

derekderek 03-10-2019 06:22 PM

Before you start rebuilding this car you need to check this birdcage and frame.

dzzman 03-10-2019 06:48 PM


Originally Posted by derekderek (Post 1599022690)
Before you start rebuilding this car you need to check this birdcage and frame.

Frame is in pretty good shape. Thats the first thing i looked at before buying it. The only pieces i can see that need replacing is the front bumper and supports. Whats the birdcage?

CA-Legal-Vette 03-10-2019 07:51 PM


Originally Posted by dzzman (Post 1599022285)
Yes theres 3 plug ins. 1 is single red wire connector, 1 single brown wire connector ,the other is 3 wires in one connector

This should be around 13 Volts, not the 9.2 that you’re getting. What’s the battery voltage?

dzzman 03-10-2019 08:05 PM


Originally Posted by CA-Legal-Vette (Post 1599023109)
This should be around 13 Volts, not the 9.2 that you’re getting. What’s the battery voltage?

The battery voltage is reading 13.1v. Ive had the battery on charge since yesterday. The single red wire is now reading 12.92v

CA-Legal-Vette 03-10-2019 08:08 PM


Originally Posted by dzzman (Post 1599023180)
The battery voltage is reading 13.1v. Ive had the battery on charge since yesterday. The single red wire is now reading 12.92v

Much better! If you have a spark plug out (or a spare), put one of the plug wires on it and lay it on your intake. Should be able to see and hear a spark when you turn it over. Dim lights help see it.

dzzman 03-10-2019 08:15 PM


Originally Posted by CA-Legal-Vette (Post 1599023191)
Much better! If you have a spark plug out (or a spare), put one of the plug wires on it and lay it on your intake. Should be able to see and hear a spark when you turn it over. Dim lights help see it.

Theres no spark at all. I even braved it and held on to it expecting to get a jolt and nothing


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