Hi Guys,

I spend a few weeks trying to make the '79 C3 L82 run again. I tried new sparkplugs (all of them are giving sparks now), the fuel line was leaking (that's fixed now), and compression is good on all cylinders. The only thing that comes to my mind now is igniting timing. So I ordered a timing tool, but in the meantime, I wanted to check if anyone here has other ideas.

Thanks,
Blaze

 

Well, I'm not exactly new to this. I'm a mechanic with 50 years experience. But I've always told my customers I can't fix it over the phone.
so, let's back up a bit.
Was it running fine and then just died on the road? Was running one day, you shut it down and the very next day it wouldn't start?
You have spark on all 8 plugs you say, this is good.
Any reason you think it could have been knocked out of time???
the basics are this. 3 things to make it run. Spark, compression and fuel.
You say compression is good but you didn't recite any numbers. You have spark but are questioning if it's at the right time. This one begs to answer the question of what changed that makes you think that.
And then there's fuel, or more appropriately the correct air/fuel mixture.
before I started to mess with timing, unless of course you know it's been messed with. I would install all of those plugs back into the cylinders that have 180 PSI of compression and make ABSOLUTE certain that each plug wire is connected to the correct plug.
then I would crank the engine while spraying carb cleaner straight into the carb intake. If it fires and runs on the carb cleaner but won't stay running after you stop spraying. You have a carburetor problem. If it won't fire on carb cleaner, you most likely have an ignition problem.
there you have it. A place to start.

 

Thanks for the quick reply. Apologies for not giving more context on my C3. Let me try to fix that:

1. I acquired it a few weeks ago. It was not running since 2013. The prior owner said that the transmission needs to be rebuilt.
2. In my initial examination, I discovered: a bad starter (the starter harness had bad wires, some of the ignition fuses were out, starter solenoid was bad), messed up and broken ignition wires not arranged in typical L82 firing order, and leaking fuel line. So far, I have addressed all these and got a spark in every cylinder. I also changed all of the sparkplugs and spark plug wires.
3. All of the eight cylinders have compression in the range between 147-150 PSI ( below 180, but in line with something I found online: https://www.corvsport.com/1979-corvette-specifications/)
4. I Tried firing it up with starter spray. The engine starts and runs as long as I keep spraying, but as soon as I either disengage the starter or stop spreading, the engine shuts down.
5. Regarding the ignition timing, I kind of thought that someone messed with it because all the spark plug cables were messed up.

As you said, it must be the carburetor. It has Edelbrod 8867. Unfortunately, I don't know much about the carburetors - other than the general principles of how they work and how to tune them - since most of the cars I worked on are newer with electronic fuel supply systems. That being said, I would appreciate any guidance on what to do next with the carb.

Thanks!

 

See if the fuel pump is bringing gas up to the carb by disconnection the fitting at the carb and into a can so you don't spray gas everywhere.

 

Since it' been sitting for 9 years. What is the quality of the fuel in the tank? It's possible that the fuel has degraded and varnished the sock in the tank and lines. If you can borrow a vacuum gauge and hook it up to the intake side of the pump to see if it's generating a vacuum. If not, then it's the pump. if it does, then the fuel lines/tank are the issue. This is assuming the fuel quality is good.

 

check that volts to coil at key in run is ther


and fuel getting to carb

 

Yes, I did this when I fixed fuel lines. I also installed an additional filter before the carburetor, so I guess that fuel quality should not be an issue, at least for few minutes

 

The fuel tank was empty when I acquired the car. The car has an intake filter before the fuel tank, and I placed one more filter before the carb. To me it seemed as a good flow.

 

OK, so you are getting fuel up to the carb?

 

Yeah. 100%. I put the pipe into a can and cranked it for a while to verify that I was getting fuel to the carb.

 

One possibility is the float needle, which allows fuel to enter the bowl is stuck, causing a fuel starvation. You can try tapping the carb where the needle sits very lightly to try to free it up. If that doesn't work, then the carb top has to come off.

 

I'm not familiar with that carb but there should be a TUBE sticking up that you can poor an ounce of gas into.
See if it will run doing that.

You say you have a spark so see if the rotor is pointing at the #1 spark plug wire when the #1 cylinder is at TDC on the compression stroke.

How about a photo of the carb with the air cleaner off.

 

ok, i removed top of the carb. All clean, full of gas. When I press throttle I can see sprayers spraying fuel. I am definitely back to ignition timing idea. Here are some pics.

 

OK. I don't see a tube to pour gas into the carb and since when you move the throttle lever you see gas being sprayed into the primaries then you have gas in the carb.

Firing order 1 8 4 3 6 5 7 2. Double check that.
Remove the #1 spark plug and verify you are on the compression stroke. (Front plug on the left side).
At TDC does the pointer and the mark on the balancer line up?
Was the distributor ever removed?
Or was it turned?

 

If it fires and runs while spraying starter fluid or carb cleaner down the carb. It's not the ignition.
it may or may not be optimal. But that's not "It".
As it does run when you spray.
Just that you see fuel when pumping the throttle is only telling you that the accerator pump is working. This car sat a long time. Most likely with fuel in the carb. The inside of that carb is likely all gummed up and fuel metering jets are plugged.
If carburetors are not your area of expertise. Then remove it. Taking lots of pictures as you go so you know what line goes where later.
take it to a known good rebuilder in your area or buy a new one.

 

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Are you trying to start it with that bottom hose unplugged?

 

how much fuel in 30 seconds in volume and what pressure?

 

From your picture it looks like the ignition wires are wrong . See picture

 

Also that looks like an Edelbrock 1406 600 cfm carb . The number is on the passenger side , in front of the mounting stud.