replaced alt, new batt, won't start

[Dennis N.]

I just finished putting in a new Optima battery and a new (rebuilt) alt.
I'm getting the same response as before...turn the key, everything goes dead, lights go out inside and batt reads dead on the batt charger.
It's a 427/400 with TI.

Arrrrgh! Please give me some ideas..thanks

[Roy B.]

Re: replaced alt, new batt, won't start

Are you saying that you put a NEW battery that was charged up in your Corvette, then tried stating the engine but wont start, then you checked the battery right after and it was DEAD. What???

[Stephen L.]

Re: replaced alt, new batt, won't start

If I read this correctly, when you attempt to start the car the lights go out and you get a total discharge indication on the ammeter. When you releaqse the key from the start position do things come back to normal? Lights on and a small discharge indication. If so you may want to check the starter for a major short/meltdown. If the starter is shorted or part of the starter circuit this would cause a major drain on the battery, a possible meltdown of the battery cables etc. You may want to have the starter checked for shorting.

[Chuck R.]

Re: Questions Questions

What year?

Does the electrical system seem Ok without turning the key? Dome lights nice and bright? Will the headlights come on and cycle from low to high Ok? Do the brake lights come on nice and bright?

Do all other ancillary systems seem Ok when the switch is in the run position? Heater blower motor. wipers, radio etc.?

I'm trying to understand if the ancillary electricals are contributors or not.

Does the connected battery hold a good charge without touching the key?

If the system goes dark and dead only when the key is turned to the start position, I would lean towards a dead short in the starter/charging circuits or even a bad switch.

If it were a non-grounding issue, I would think that the battery wouldn't be hit as hard as your explaining Dennis.

I would disconnect the wires from the alternator, tape them off and see if you get the same problem when you hit the switch. If not, then you have got it narrowed down to either a mis-wired alternator or another wiring short.

Just thinking out loud Dennis. I'm sure other's who have ridden down this same road will chime in to help.

I'll be interested in what you find.

Chuck

[Wayne W.]

Re: replaced alt, new batt, won't start

Sounds like a bad connection. That could be a cable, possibly at the starter, or even the bulkhead connector.

[Dennis N.]

Re: Questions Questions

Left battery on full charge overnight. This morning all the lights and other electrical features worked fine. As soon as I turned the key..everything went dark. Battery dead again. Again, new rebuilt alt, brand new Optima battery.
Still need help, but all the ideas are gonna be pursued tonight.

[Les Jacobs]

Re: Questions Questions

Dennis I had a similar problem and it turned out to be the battery cable connections. Suggest you get a voltmeter and connect directly to the battery posts. Then hit the key, watch the voltage reading. I would expect the battery to remain good even though the rest of the accessories don't operate. By leaving one probe (minus) connected to the battery post and moving the other , you should find the problem. If not, reconnect the (plus) terminal and move the minus probe. In my case, it was a battery cable connection at the battery. When cold it made a good connection. When hot, it didn't. So car would start cold and run, but then die when I turned the lights on. I also had no juice until I wiggled the cable connector.

[Dennis N.]

Re: replaced alt, new batt, won't start..UPDATE!

Just crawled out from under the 67. Having a terrible short problem. Hit the key, everything goes dead..lights and battery! I received a lot of good ideas from the forum. Bought a new cable set today and am trying to install it. I now know what I want for Christmas...a lift. Crawling under the car while it's on stands on cold concrete is a pain. The cable at the starter solenoid is worse than bad. On top of that, 2 other wires were fused into the cable. Could be my problem, huh?

About those 2 other wires that were fused into the pos cable....they were a red and a black going into 2 separate black cylindrical gizmos. When they came out the red wire was purplish and the balck was orange. They joined into a flat ring fitting (like on the end of the pos cable) and this was on the starter solenoid, also. The light purple wire was fused into the pos cable and one of the balck cylinders was melted into a drip, but not exposing the wire. The light purple wire was exposed when I peeled it off of the pos cable. The end of the pos cable was split back and the wire was exposed. It was very brittle and corroded looking.

Questions...what are the 2 wires attaching to the solenoid? How do you keep the wire insulated from the exhaust manifold, which seems to be right there by the wires?

Thanks for your advice.

[Wayne W.]

Re: replaced alt, new batt, won't start..UPDATE!

Sounds like a mess. Repairing the cable melt down may solve the problem, but then again it might not. One of two things is going to happen when you first start it. The true short will show up and fry the things again, or it will operate normally. You may be just fixing the symptom of the problem, a bad starter.

[Rob A.]

Re: replaced alt, new batt, won't start

I have the same engine in my '67. It is difficult to route the wires and battery cables between the block and the exhaust manifold. Are you using the clip that attaches to the solenoid to hold the wires in place? Use something as a spacer between the block and the wires while you tighten them to the solenoid, otherwise they move when you tighten the nuts. I used a plastic zip to tie to hold them where I wanted them while I tightened the nuts, then removed it. I went through a set of spring ring battery cables when the positive was just barely touching the block, which melted the plastic and shorted out and ruined the battery and destroyed the cable. Sounds like you're having somewhat of a similar experience. If your positive cable melts and the wire touches the block, which is attached to the negative cable, it will destroy the battery. Hope that helps...

[Dennis N.]

Re: replaced alt, new batt, won't start

Eureka....replaced both cables and the car started!
Thanks for all the help, I gotta get that clipo to hold the wires away from the block and the manifold.
On to the next problem. Thanks again guys.

[Mike B.]

Re: replaced alt, new batt, won't start

Dennis,

For your info, those two smaller wires are vitally important. One backfeeds 12v to power most everything in your car. That is the one that shares the post coming from the battery. The other comes from the key and energizes the solinoid on the starter. That was likely the real culprit and gave the symptoms of the battery being dead when you turned the key. In fact, it was open circuited by the corrosion, melting or both. Better that it happened in your garage and not in some parking lot. The ground is even colder there without the jackstands!