12 volts at the block?
Thread Starter
Heel & Toe
Joined: Mar 2024
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12 volts at the block?
So I've been investigating a no spark condition for a little while now. I've learned some things and talked to people. Now I'm down to this.
No spark. Unhooked batt. Put tester to batt wire on distributor. 12 volts? Touched it to block. 12 volts. I've been told time and time again about a ground issue but I can't figure it out to save my life. It cranks but won't start. Some times I get a glimmer of hope and it coughs but not often enough to matter. I've added additional 12 gauge grounds to both sides of the block leading to the frame. Still 12 volts. Brand new plugs, new wires, distributor, ignition switch. Straight wired the distributor batt wire to a radio fuse for turn key power instead of constant. So much research and so little results. The last thing keeping this thing from firing off for the first time in a long time. Yes it's in time.
No spark. Unhooked batt. Put tester to batt wire on distributor. 12 volts? Touched it to block. 12 volts. I've been told time and time again about a ground issue but I can't figure it out to save my life. It cranks but won't start. Some times I get a glimmer of hope and it coughs but not often enough to matter. I've added additional 12 gauge grounds to both sides of the block leading to the frame. Still 12 volts. Brand new plugs, new wires, distributor, ignition switch. Straight wired the distributor batt wire to a radio fuse for turn key power instead of constant. So much research and so little results. The last thing keeping this thing from firing off for the first time in a long time. Yes it's in time.
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How did you determine the distributor is correctly installed?
Since the engine cranks there is no ground issue.
Not clear what 12 volts at the block means?
Since the engine cranks there is no ground issue.
Not clear what 12 volts at the block means?
Last edited by MelWff; Jun 14, 2024 at 07:49 PM.
Thread Starter
Heel & Toe
Joined: Mar 2024
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NOT my brightest Idea but it has had 3 distributors, the original, one I installed, and one I had installed by a mechanic friend at a shop. I've watched them be installed and watched more than a healthy dose of YouTube tutorials. I was hoping I installed it wrong before we put the newest one in.
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Thread Starter
Heel & Toe
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It's wild how many Corvette people I've asked, classic car guys at shows, older mechanics, younger guys, car guys, hell even a guy who's built one from the frame up! He even gave me all of his wiring diagrams and books cause he said he'd never do another one again.
I'm just stumped on this, and have been for a couple months now taking breaks in between to try and recollect everything I've been learning about the car.
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Everyone I've asked can't seem to find a reason why it won't run. The tester I used has a digital volt meter and when you stick it to the block anywhere it reads 12.6 volts. Both of the connections were on the battery pos and neg connections.
It's wild how many Corvette people I've asked, classic car guys at shows, older mechanics, younger guys, car guys, hell even a guy who's built one from the frame up! He even gave me all of his wiring diagrams and books cause he said he'd never do another one again.
I'm just stumped on this, and have been for a couple months now taking breaks in between to try and recollect everything I've been learning about the car.
It's wild how many Corvette people I've asked, classic car guys at shows, older mechanics, younger guys, car guys, hell even a guy who's built one from the frame up! He even gave me all of his wiring diagrams and books cause he said he'd never do another one again.
I'm just stumped on this, and have been for a couple months now taking breaks in between to try and recollect everything I've been learning about the car.
Race Director
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From: Virginia
Photos help! We might notice something obvious. Something your mechanic buddy missed.
How do you know the timing is correct if it doesn't run? Do you have a timing light? You could use a spark plug, or the timing light will detect firing in the ignition wires.
How do you know the timing is correct if it doesn't run? Do you have a timing light? You could use a spark plug, or the timing light will detect firing in the ignition wires.
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Thread Starter
Heel & Toe
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we are.touching it to the bolts on the valve covers. The black lead is grounded at the battery
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Thread Starter
Heel & Toe
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And about the plugs we've used in line testers, touching it close to the frame. I put my finger on it😅. and we've tested them all.
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If you get zero when cranking it won't start. Check the new ignition switch.
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The meter your using looks like a issue. Take a standard run of the mill test light. Clip your ground on the battery, with enough wire to reach the block. Touch the end of the test light to the block. Light come on?. Not likely. Take the ground leed and put it on the positive terminal of the battery. Touch test light to block. Light comes on? Normal.
your testing procedure is confusing everyone.
Take a couple feet of wire. Connect one end to the large terminal on your alternator with all other wires still connected. You now have a hot wire, be careful. Connect the other end to the batt, or positive terminal on your distributor. Crank engine. Does it have spark now?
your testing procedure is confusing everyone.
Take a couple feet of wire. Connect one end to the large terminal on your alternator with all other wires still connected. You now have a hot wire, be careful. Connect the other end to the batt, or positive terminal on your distributor. Crank engine. Does it have spark now?
Race Director
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From: Virginia
So the one photo you post is of the tailgate of whatever tiny SUV you have nearby?
Help us help you, and post some actual photos.
EDIT: Prior threads with photos. 79 with HEI (so the starter bypass power is not the issue).
https://www.corvetteforum.com/forums...rter-area.html
https://www.corvetteforum.com/forums...-no-spark.html
Do you have a buddy who really understands electronics? An hour with a multimeter should get to the bottom of this problem.
Here are some wiring diagrams.
https://wordpress.keystonestatecorve...m/?page_id=118
Help us help you, and post some actual photos.
EDIT: Prior threads with photos. 79 with HEI (so the starter bypass power is not the issue).
https://www.corvetteforum.com/forums...rter-area.html
https://www.corvetteforum.com/forums...-no-spark.html
Do you have a buddy who really understands electronics? An hour with a multimeter should get to the bottom of this problem.
Here are some wiring diagrams.
https://wordpress.keystonestatecorve...m/?page_id=118
Race Director
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From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
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No I don't think that's the answer. He does say the starter cranks. So that can't be possible.
Much more likely our friend has very little experience with electronics and how to properly use his meter.
That's why I suggested using a simple test light.
And others suggested getting help from a friend with electrical experience.
Much more likely our friend has very little experience with electronics and how to properly use his meter.
That's why I suggested using a simple test light.
And others suggested getting help from a friend with electrical experience.