Hello to all,
New forum member here, new C3 owner, and this is my first post. Have been looking over the forum for guidance, but at this point I could use your collective experience to get back on the road.

Purchased the car 3 months ago. It’s a 1980 L-48 with 4 speed manual trans. Engine looks to be unmodified. PO had catalytic converter removed and Monza exhaust installed. Battery is newer. PO had a quick disconnect installed on the battery.

Since purchasing, I replaced the spark plugs, wires, distributor cap, rotor, coil, and ignition module. Had oil leaks at both valve covers. Replaced the stamped steel covers with aluminum L-82 finned covers and Felpro silicone gaskets. Removed the emissions as they were inoperable and were the source of some vacuum leaks. Have kept the removed equipment. I have an AIM and a Chilton to reference.

Car was running. After visiting a store a mile from home, the engine would turn over, but would not start. Verified that I was getting fuel. As I have read horror stories about bad ignition modules I reinstalled the old one in the parking lot, but no change. Had the car towed home.

Now the car will not turn over. When key is turned to ON there is no power to the dash. No solenoid clicking heard or action from the starter.

All accessories are dead. All fuses under the dash were good. The two rectangular metal relays in the fuse panel were not tested. (Not sure how to perform). Checked that the battery’s positive terminal/ quick disconnect and negative terminal connections were tight. Went under the car and cleaned the frame to bare metal and secured the battery ground cable.

Voltmeter readings taken with the clutch depressed, shifter in Neutral, and key turned to ON:

12.88 volts at Battery terminals. Had battery on a wall charger prior to testing.

12.83 volts at PURPLE wire, (at back of center arm rest behind seats). Positive probe stuck into plug and negative probe on negative terminal of battery.

12.59 volts at main harness plug in the engine bay. Hot reading taken from the lower half of the two part plug, where the harness descends to the starter.

0.05 volts at top of solenoid where the harness and black cable from the battery connect together. As I was under the car and kinda of blind, I’m not sure how solid this reading is. Did take it in several places at the connection bolt with no change in reading.

Wasn’t aware of what fusible links were until recently. On my car there is the black battery cable and 4 wires from the firewall harness that converge at the starter solenoid.

If I understood the AIM schematic correctly it only shows 2 wires, red and purple connecting with the black cable from the battery.

Guessing this car’s wiring is a later addition as it has 3 wires coming in from the harness.

On the harness side there are 2 plastic casings and 1 solid wire. Wires colors are all basically some shade of red. One of the two plastic casings has 2 wires going in and merging to 1 wire out. The other plastic casing has 1 wire in and 1 out. There is no obvious way to open the casings, as if there was an internal fuse. Maybe you can, but wanted to check with you all first before creating another issue.

I assume that the single wires between the plastic casings and starter are the fusible links.



As I understand it the ignition switch and neutral safety switch could also be at play. I haven’t checked these. The seats, carpet, and center console are out of the car so I’m in a good position to look elsewhere if need be.

I’m open to any and all suggestions or corrections to identifying the issue(s).

Weather is turning nice and getting itchy to drive! Thank you in advance for any knowledge you offer.

 

Rookie suggestion.......
Test the wires in the picture closest to the starter. If those are good fusible links you will see 12V when you probe the wires coming out of the plastic shield. If they are burned fusible links you will have 12V at each wire going into the plastic shields, but NO voltage in the wires coming out of the shields.

(It may be that one of the shieled wires is sending 12V to the firewall fuse box)

 

Thank you DoorGunner! Will check it out this week when I can get back under the car. Will post my findings.
Had a good laugh at “rookie suggestion” after viewing your thread. Your far from being a rookie sir!

 

definitely sounds like it could be the fusible links.

 

...one simple test I learned to do was to try and start the car with the headlights "ON". If they dim heavily, you most likely have a locked up starter. Have had this happen on a few older GM vehicles that I owned in the past.

...also was fooled one time into buying a new starter for my '75 Corvette. Showed I had good battery voltage, but found out I did not have battery "power" or amperage. Changed out battery, same result. Then I checked the heavy black battery cable to ground on frame below battery box. The sheathing on the cable look like it had swallowed a mouse. I cut it open with a razor knife and it was 90% powdery white corrosion. Even though I had a good battery, the cable could not pass the voltage or cold cranking amps through all that corrosion. Replaced the battery cable, car fired instantly. Lesson learned. I replaced the battery & starter when they were fine.

 

Replaced the fusible links. Still no power to the starter. Went back and checked the battery ground cable and found it was corroded like Paul had experienced. Replaced the cable and had intermittent power, enough to make the key buzzer come on. Car came with a battery shutoff switch. Even though I had checked its connections and tightened the positive battery post, I can move the positive wire to the starter and interrupt power to the key buzzer. Will remove the shutoff and connect straight to battery. Then go from there!

Corroded ground cable from battery

 

Im putting money on the battery disconnect. Bought an 81 last year and randomly would just not start. Found the disconnect and removed it. Zero issues since

Cole

 

In most vehicles the NEG-GRD wire, or cable is under the hood where its somewhat protected from the elements and road grim.

Not so, on a C3. Its exposed to everything and takes the brunt of rust & corrosion.
That's the first place to inspect on 90% of electrical gremlins.

 

It’s turning over, but no spark. I was actually excited just to hear the starter running strong and the console lighting up - LOL! Now at least I’m back to where I started (no pun entended). Pulled the battery to distributor wire and it’s getting power, 12.77 volts.
Tach wire was dead. Spark plugs, plug wires, distributor cap and rotor are new. Currently have the original ignition module installed, but will change it back to the new one and go from there.
Don’t have my hopes up with the module change as the car had no spark with the new one installed.
I’m all ears on direction or suggestions. Thank you in advance!

 

 

So, now, you have crank, weak spark, no start.

Your last events were new cap, rotor, modge, etc.

I think I would double check the connection harness to the module. Look for corrosion on the spades.
Remove coil dust cover and inspect the spring bushing under the coil. Make sure the bushing protrudes ALL the way thru and is visible under the cap. The bushing must be able to make contact with the rotor or arcing / weak spark will occur.
Even with a new cap, you may have the rubber washer wrong or the wrong resistance bushing. (Low or High)

Then, verify black GRD wire is "cleanly" attached to one corner of the coil frame.

Don't forget, the modge gets Heat-Sink-Compound applied underneath.