Losing Voltage at Firewall

[sic71]

While out on the town today, I noticed my car having difficulty starting after a few stops, as if the battery were dying.  I managed to get it home  and upon shutting it off and trying to restart, the battery was dead.  I got my meter out to get some readings only to find out my 20 year old meter has finally bit the dust.  I put the battery on charge while I went to town to get a new meter.  Battery is charged but only reading about 12.9v at the battery while running.  I then measured at the alternator and am getting 14.18v.  I maintain that voltage all the way to where the wire enters the firewall but get 12.9v once it comes back out of the firewall on its way towards the battery.  What do I need to be looking for?  Thanks

Travis

[Chryco Psycho]

fiewall plugs look for signs of heat / melting
 Bad ammeter , you can alway run a 10 ga wire from the alt output to the starter relay battery terminal & take all of the load off of the firewall & ammter

[burdar]

   The bulkhead connector is a weak point in the system as well as the AMP gauge.  Pull the bulkhead connector apart.  If everything looks good(not melted) then give it all a good cleaning.  Plug everything back in and use some dielectric grease to seal out any moisture.  Recheck the voltage.  You can also recheck the voltage on the interior side of the bulkhead.  Also look for signs of heat at the AMP gauge.  If you see a problem there, connect the two ends together to bypass the gauge.

Running a dedicated charge wire(8 gauge) is also a good idea.  In the stock system, the alternator voltage needs to go through the bulkhead "twice" before it reaches the battery.  The dedicated charge wire takes that load off of the bulkhead.  The only issue with adding the charge wire is that the AMP gauge won't work as designed.  With the battery being charged by the jumper wire, the AMP gauge won't read that voltage going through the system.

[YellowThumper]

That weak point at the firewall is a long known issue. It has been the source of many fires. Inspect and bypass if there is visible heat damage. It will only get worse as time goes on. Please be very cognitive of this.

Mike

[BS CUDA]

That week point at the firewall is a long known issue. It has been the source of many fires. Inspect and bypass if there is visible heat damage. It will only get worse as time goes on. Please be very cognitive of this.

Mike

As above - just do the bypass NOW!!!! Takes only a couple hours. I kept putting this task / upgrade aside and it ended up costing me every bulb in the car, my MSD box, my tach, my AFR gauge, my battery shut off switch and a tow truck ride home. Fortunately it stopped short of lighting the car on fire.

[sic71]

fiewall plugs look for signs of heat / melting
 Bad ammeter , you can alway run a 10 ga wire from the alt output to the starter relay battery terminal & take all of the load off of the firewall & ammter

Run an additional wire or eliminate the ammeter wires altogether?

[burdar]

Bypass the meter by connecting the two wires together. The amp gauge is a weak point. The additional charge wire is a separate modification. That mod will take the load off the bulkhead fitting by directly charging the battery. You can upgrade the electrical system even further by installing relays in the headlight circuit. This mod should eliminate the dim lights at idle. Any additional electrical loads should be wired through relays in order to protect the stock wiring.

[Chryco Psycho]

the fastest way to eliminate the ammeter is to bolt both wies to either of the studs on the gauge