Hey all. I'm looking for any help that i can get. This is the deal, I recently installed a pertronix distributor w/a flame thrower 2 ing mod cuz, i was having all kinds of issues with the dura spark 2 mod. So i rewired the ingnition system and also install a custom dash. Which also called for new wiring.
Just a note on my back round, I've built many harnesses for people and for my 65 & 66 Galaxies and 79 F150 but never had any problems like this.
Here goes, my 77 F100 has a new alt., starter and relay, volt reg., coil, billet pertronix distributor, timing chain, dash gauges and key ing. switch.
Last night i set the timing and had it running like a swiss watch. Let it run to operating temp then shut it down. About a half hour later, cranked her up with no issues and checked everything.
No problems found.
After 2 or 3 hours, went to start it and click, click, click, click, click, click, click.
Checked the battery, it read 12.58. Turned on the lights and tryed. click, click, click, click. Lights got dim then went out completely. The volt meter went nuts, Down to 9v then 7v then 3v while trying to start it but went back up to 12.55 when i shut it down. Charged the bat to 12.68, turned on the lights without cranking and they came on very very dim and bat went nuts again with different readings in the 6v range. Then, after about 10 to 20 seconds, the lights got normal bright and the bat read 12.10. Turned the lights off and the bat went to 12.53 and in about a minute, to 12.57.
I've checked all connections and grounds, everything test good. But it still happens and won't start .
Any ideas on where i went wrong or what i wired wrong?

 

This is probably stating the obvious and no insult is meant but are you sure the grounds are good?
The symptoms you list sounds like the classic bad ground.
Is the battery grounded to the engine block? Is the ground cable new? If not are you sure its good? They can "look" okay and still be bad. What about any grounds to the dash, engine compartment.

 

First rule out a timing change hasn't caused an over draw on the starter

All grounds is where I would start ..

I would make sure the solenoid has a good ground to the inner fender well
The battery to motor ground
The firewall to motor ground
The alternator is grounded

Edit: You were quicker Mike

 

Bad battery. Seen it too many times to count. Get a new one in there and you'll be running again.

 

bad battery even thou it holds a charge? when i charge it, it goes to 12.68 and stays. could be something i wired wrong?

 

Thanks all. Gonna swap bats with my 65 Galaxie, it's new and go throu all my grounds again. Would it be wise to run all grounds to battery to block ground point?

 

Yep, even though it has good resting voltage. You diagnosed this yourself as soon as you said it dropped below 10 volts when trying to crank.

 

I had an Optima (red) that did that...

 

Yeah, Thats what mine is, an optima red. thanks fellas.
i'll post my progress.

 

Holy Coinkadink Batman!

But first eliminate all the easy stuff like grounds, dirty terminals, and loose connections. The missing/bad ground that really throws things off is the block to cab firewall bonding strap. I swapped to EFI and forgot to reconnect it... talk about weirdness! Hooked it back it and experienced a truckgasm when the EFI fired her up.

My 71 hates me because I haven't touched her in a couple of months. The '70 probably hates me for not driving her lately.

 

Coinkadink?

 

co-in-ka-dink......'Coincidence'

 

Grounds and batteries can drive you nuts at times. A starter/alternator shop told me a few weeks ago that " a battery can show good voltage but have low amperage and can show good amperage but have low voltage" . Made me think a bit deeper on my '05 F150 problem. Gary

 

Hey HIO, where is the block to cab ground strap located? I don't see it on my truck.

 

I've had a bunch of batteries that test fine voltage wise, but have lost their cranking abilities. Have one in the garage right now. Everything in the truck works but it does nothing when turning key. Won't even start jumping the solenoid. Tried another battery and started right up