I have my battery mounted in the trunk of my '75 and if the car sits awhile (2weeks +) the battery current gets low the car will not turn over, the car appears to have some power (headlights, radio) but doesn't even try to crank.

My battery ground is mounted to a brass stud above where the battery normally is... and I am wondering if this may not be mounted in the correct spot... Or maybe I just have a bad starter.

So where is your battery grounded???

How old is the battery?
have you done a load test on it lately?

Load test it. I just put a brand new Wal-Mart battery in my trailer that died the other day. It turns out the the battery that I thought was brand new is 4 years old according to the receipt. I guess it's not brand new anymore.

The stock grounding stud is on the passenger's side near the firewall. It sounds like where yours is connected.

forget it

My Battery is pretty new, I bought it about 1-2 years ago. I used to have this problem more often, but I bought a new battery that had way more cranking power than needed, I disconnected the battery while it sat and the problem pretty much went away, until recently.

My main concern is that the car never cranks like the battery is low, it either cranks normal or not at all. Maybe I should trade the battery in for a new one? I know its a little hard on the battery when you don't use them alot...

The grounds are good, but I'll double check that there is not any build up on the connections of the trans ground strap.

Here is what I found out.
The ground circuit has to go through the body to the trunk, down the tranny ground strap (which is old and flows less current) and through the motor to the starter.

That is a long way.
What I did was run a dedicated 10 gauge wire from the ground post on the batter to the lower starter bolt. 10 gauge can handle 30 amps or more.
I may be wrong in the size number, but its one step down from a battery cable in size...

If you compound the fact that the tranny ground strap is weak, the starter is weak, the starter ground strap is weak (little one on the starter) then you end up loosing alot of amperage by the time it gets to the starter.
An old starter draws alot more current than a new one due to the binding that is occuring in the starter bushing.

So, add the new wire, run it along the firewall portion between the trunk and the engine bay and through the extra gromet near the starter, simple.
Leave the original ground strap from the battery to the body in place, that will service the chassis elec, light etc.

Rich

you would be better off getting a new ground strap.
They loose consistency over time and age.
They flow less power.
New cables do wonders.
And clean all the connection areas with sandpaper down to bare metal, then use either vaseline or elec grease to prevent further corrosion.
Rich

Actually the strap is new, the old one was broke when I took the trans out of the car.

But I agree that the ground circuit has to travel a long ways. In my chevelle the the ground goes to the block and is about a foot from the starter... seems like much less traveling distance.

How did you connect the second line to the battery? I do think my current battery ground cable has a 10 ga wire coming out of it...

After you check all of the basics as described in previous posts there is
another thing that just occured to me. It is common to develop start circuit problems along the many connections between the ignition switch and the starter solenoid over the 35 years or so that the car has lived. Many people have installed a relay next to the starter to assist. This way the cranking circuit only needs to supply enough current to energize a relay rather than enough to energize the solenoid. This is a band-aid that masks other problems, but it works. It could also be the ignition switch. A small spark is generated inside the ignition switch every time you crank the starter and it will eventually erode the critical contacts inside the switch.

I forgot about the switch...that does produce the on off type scenario also.

I left the large wire going to the body and added the additional wire to the starter.
I also replaced the ignition switch, it failed at another time.

Also, if you have the "logic circuit" relay under the passenger seat, that is a problem area also.

Rich

I have a drain somewhere on my car as well. I have not been able to pinpoint it yet though.

If you compound the fact that the tranny ground strap is weak, the starter is weak, the starter ground strap is weak (little one on the starter) then you end up loosing alot of amperage by the time it gets to the starter.

Rich
[/quote]

I snipped a bunch of this for brevity. WHAT "little one on the starter"? There IS NO ground strap on the starter. The Cap'n

[quote name='Cap'n Krusty' date='Apr 8 2008, 09:09 PM' post='1018189']
If you compound the fact that the tranny ground strap is weak, the starter is weak, the starter ground strap is weak (little one on the starter) then you end up loosing alot of amperage by the time it gets to the starter.

Rich
[/quote]

I snipped a bunch of this for brevity. WHAT "little one on the starter"? There IS NO ground strap on the starter. The Cap'n
[/quote]
Goes from the relay to the body of the starter.
Small, flat, copper, braided, weak...
It is attached to the other large nut on the relay...

Rich

The ignition switch is an excellent suspect if the cranking is good but intermittent.

Told you I may be wrong on the gauge...
Its one step down from a battery cable...about 1/4 inch thick.
Works great, no melting...I have been watching like a hawk.

I changed everything...then added this and it never EVER does it anymore.

Dont know the gauge, sorry.
Rich

forget it

Thanks for restating your point. I hope you feel better.
This place is really getting a bit negative...must be the economy.

The addition of a wire, especially a wire for grounding purposes does not need to be so large. This wire is not replacing anything, just adding onto an existing system.

Dave, I have done this, more than once. I have actually gone out in my shop, added this wire and worked on my car. I am not theorizing nor bench engineering.
While on paper you theory may be valid. I have a real world application on TWO cars that both have survived for three years, no melting, no problems. Yet another theory disproven by a FACT.

Once again. The addition of an extra ground wire is not replacing anything. It adds additional pathways for the current, shorter pathways for the current.

Please stop with the negative "I am smarter than you crap" its really getting old. You dont need to read or comment on any thread, and certainly not twice saying the same damn thing..just so you get the last say...

I got your point, dont do it. You dont like it. Fine...

Rich

Hmm... Starter ground... haven't checked that.

Well current will take the path of least resistance, so if you leave the big cable on, any additional cabling can only help.

r_towle- did you cut off the original battery connector and add the extra wire by using something like this? (not neccesarily with a lever)

years ago, yes.
I have that same type of connector, just has two wires in it now.
A actually bought a nice one, I never liked that tab that bolts down, they tend to bend...
The newer japanse ones have a better setup and are now at all the local parts stores.
Rich

My stock ground post was rusty enough underneath the paint it broke off when I torqued it a bit. My battery is now grounded to the fan housing. Works great. New battery, new starter, and new ground cable solved my intermittent start problem...getting the good ground was the final solution. Not sure if yours is good? Just unhook it and run a jumper cable to the top of the fan housing, crank and compare.

I moved my battery to the trunk. So, I am grounded to the ground strap on the transmission.