A little help from the experts…
#1
8th Gear
Thread Starter
A little help from the experts…
Hello folks I’m a bit new to these forums but I’m needing help with suggestions on finding out why my 79 Vette won’t start for me. About a week ago I was leaving for work with it and all of sudden my engine stopped, lights shut off, and radio shut off. I parked the car tried cranking and nothing no crank, eventually after testing crank the lights all came back on but still no crank. After getting off work that night I came home to check things out and now it’ll crank but no start. Here’s a list of things I’ve done…
Took off starter and alternator and had both checked, they were both good.
Changed out battery but still no start, checked both battery’s and their both good.
Found a bad wiring harness connector going to the alternator and replaced it while I was at it but still no start.
Ran a load test off the battery while I crank and I’m getting a massive drop in voltage when I crank so I know that might be part of the problem.
Checked all ground connections and they’re all good as well, some were a little gunked up and dirty but connections were good.
Checked distributor and that’s basically brand new inside and out from being changed out a long time ago.
I have heard of people bringing up a fusable link but with all the books and all the searching I’ve done I can’t find them for the life of me and the previous owners of the car at one point rewired the entire car so there’s wires cut up and not going to anything at all and all kinds of weird stuff but everything has been running great in it since I bought the car so I never questioned it much.
Took off starter and alternator and had both checked, they were both good.
Changed out battery but still no start, checked both battery’s and their both good.
Found a bad wiring harness connector going to the alternator and replaced it while I was at it but still no start.
Ran a load test off the battery while I crank and I’m getting a massive drop in voltage when I crank so I know that might be part of the problem.
Checked all ground connections and they’re all good as well, some were a little gunked up and dirty but connections were good.
Checked distributor and that’s basically brand new inside and out from being changed out a long time ago.
I have heard of people bringing up a fusable link but with all the books and all the searching I’ve done I can’t find them for the life of me and the previous owners of the car at one point rewired the entire car so there’s wires cut up and not going to anything at all and all kinds of weird stuff but everything has been running great in it since I bought the car so I never questioned it much.
#2
Le Mans Master
Member Since: Nov 2006
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2022 C3 of the Year Finalist - Modified
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Do you own a test light? Are you getting power to that clean distributor with the key in run? Do you have a wiring schematic for your year Corvette? Do you own the Gen. GM Electrical Trouble Shooting Manual?
I would start with checking that large pink wire at the distributor for power. No power work backwards through the system. Yes power than likely a distributor problem, bad module or coil.
I would start with checking that large pink wire at the distributor for power. No power work backwards through the system. Yes power than likely a distributor problem, bad module or coil.
#3
Le Mans Master
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C3 of Year Finalist (appearance mods) 2019
Take a close look at the upper connection of the 'starter extension harness'.
https://www.zip-corvette.com/79-w-ac...o-aux-fan.html
https://www.zip-corvette.com/79-w-ac...o-aux-fan.html
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#4
8th Gear
Thread Starter
Do you own a test light? Are you getting power to that clean distributor with the key in run? Do you have a wiring schematic for your year Corvette? Do you own the Gen. GM Electrical Trouble Shooting Manual?
I would start with checking that large pink wire at the distributor for power. No power work backwards through the system. Yes power than likely a distributor problem, bad module or coil.
I would start with checking that large pink wire at the distributor for power. No power work backwards through the system. Yes power than likely a distributor problem, bad module or coil.
#5
8th Gear
Thread Starter
Take a close look at the upper connection of the 'starter extension harness'.
https://www.zip-corvette.com/79-w-ac...o-aux-fan.html
https://www.zip-corvette.com/79-w-ac...o-aux-fan.html
#6
Le Mans Master
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The wires coming off the starter solenoid sound correct. Just above those ring connectors on the large terminal are fusible links. There should be 2 of them. One will provide power to the lights, which work. One provides power to most of the rest of your car. Check these closely. Check for power at every fuse. Both sides of every fuse.
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#8
Le Mans Master
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That certainly doesn't look good! You just might be on to something.
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pipocinyd (06-16-2023)
#9
Le Mans Master
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Not only swap out the coil obviously, but you really should change the cap, rotor, spring bushing and the rubber washer under the coil.
The spring bushings come in high resistance or low resistance, about $17.
When you install your new coil, a black GRD wire, or a strap goes to one of the four coil bolts in one corner of the coil. Make sure that the GRD connection is touching bare metal of the coil. Some of those coils come with a coating to prevent rust. Lightly file / clean one corner.
The spring bushings come in high resistance or low resistance, about $17.
When you install your new coil, a black GRD wire, or a strap goes to one of the four coil bolts in one corner of the coil. Make sure that the GRD connection is touching bare metal of the coil. Some of those coils come with a coating to prevent rust. Lightly file / clean one corner.
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pipocinyd (06-16-2023)
#10
The wires coming off the starter solenoid sound correct. Just above those ring connectors on the large terminal are fusible links. There should be 2 of them. One will provide power to the lights, which work. One provides power to most of the rest of your car. Check these closely. Check for power at every fuse. Both sides of every fuse.
Yes very closely like bring a nice bright flashlight & look very closely
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pipocinyd (06-16-2023)
#11
8th Gear
Thread Starter
Not only swap out the coil obviously, but you really should change the cap, rotor, spring bushing and the rubber washer under the coil.
The spring bushings come in high resistance or low resistance, about $17.
When you install your new coil, a black GRD wire, or a strap goes to one of the four coil bolts in one corner of the coil. Make sure that the GRD connection is touching bare metal of the coil. Some of those coils come with a coating to prevent rust. Lightly file / clean one corner.
The spring bushings come in high resistance or low resistance, about $17.
When you install your new coil, a black GRD wire, or a strap goes to one of the four coil bolts in one corner of the coil. Make sure that the GRD connection is touching bare metal of the coil. Some of those coils come with a coating to prevent rust. Lightly file / clean one corner.
#12
Melting Slicks
Ignition module maybe ?
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pipocinyd (06-16-2023)
#13
8th Gear
Thread Starter
newest update I went ahead and took it all back apart and checked the ignition module everything looked good basically brand new. It is now cranking but I can hear a loss in power after cranking for just a couple seconds and everything starts to slow down more.
#14
Le Mans Master
Who made your distributor? Was it $60- from eBay?
It may look new, but the ignition module can fail internally. You can buy Delco replacements on eBay. It's always good to have a spare in the car, and add heat sink compound to the back.
Did you check for 12V at the distributor?
Does your battery lack ampacity, and is discharging quickly while cranking?
It may look new, but the ignition module can fail internally. You can buy Delco replacements on eBay. It's always good to have a spare in the car, and add heat sink compound to the back.
Did you check for 12V at the distributor?
Does your battery lack ampacity, and is discharging quickly while cranking?
#15
8th Gear
Thread Starter
Who made your distributor? Was it $60- from eBay?
It may look new, but the ignition module can fail internally. You can buy Delco replacements on eBay. It's always good to have a spare in the car, and add heat sink compound to the back.
Did you check for 12V at the distributor?
Does your battery lack ampacity, and is discharging quickly while cranking?
It may look new, but the ignition module can fail internally. You can buy Delco replacements on eBay. It's always good to have a spare in the car, and add heat sink compound to the back.
Did you check for 12V at the distributor?
Does your battery lack ampacity, and is discharging quickly while cranking?
#16
Le Mans Master
Did you check the battery ground at the frame (right under the battery)? Also, check the general condition of the battery cables. make sure they aren't melted anywhere. Do the engine grounds look solid?
As for not starting, do you have fuel and did you verify that you are getting spark? Did you pull a spark plug and crank it?
I agree with Bikespace. I always keep a spare ignition module in an HEI car. They will die without warning.
As for not starting, do you have fuel and did you verify that you are getting spark? Did you pull a spark plug and crank it?
I agree with Bikespace. I always keep a spare ignition module in an HEI car. They will die without warning.
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pipocinyd (06-16-2023)
#17
8th Gear
Thread Starter
Did you check the battery ground at the frame (right under the battery)? Also, check the general condition of the battery cables. make sure they aren't melted anywhere. Do the engine grounds look solid?
As for not starting, do you have fuel and did you verify that you are getting spark? Did you pull a spark plug and crank it?
I agree with Bikespace. I always keep a spare ignition module in an HEI car. They will die without warning.
As for not starting, do you have fuel and did you verify that you are getting spark? Did you pull a spark plug and crank it?
I agree with Bikespace. I always keep a spare ignition module in an HEI car. They will die without warning.