At Ryan's suggestion I updated my new engine to include a Moroso water pump and HHR fan. The current rundown of electric parts would be:

Mallory 685 box
Moroso WP
HHR Fan
Aeromotive 11203 pump

All are run via relay. Before I put the new engine in I also took in my alternator to determine it's output and have it refurbished. The Alt shop told me that it put out 90 amps and went through it completely.

The car currently still has the original front wiring harness and is still going through the factory ammeter. I realize this needs to be changed as well and wondered if most just put both wires on one lug of the ammeter to bypass it. That's something I'll fix soon as well.

Anyway this is what I am seeing as the car runs. I get a constant 14+ volts out of the alternator and with everything but the HHR fan running I see around 13.5v at the battery. The ammeter guage reads about two-three clicks to the north during this. When the HHR fan kicks on the ammeter will go to one click south of maxed on the gauge and runs fine but measuring voltage at the battery it will be about 12.95 volts. My assumption is that the HHR fan is pretty much running off the alternator at this point? When the car is powered off the battery reading is around the same 12.8 to 12.9 volts. I was thinking maybe I should run another 6 gauge wire and fusible link directly from the alternator back to the starter relay lug etc. to possibly help the situation out? What have others done or am I fine with the 12.95 volts during HHR operation?

Thanks!

Running the fan on the factory through-the-bulkhead-connector circuit is a recipe for an electrical fire. The fan needs its own 10 ga. wire from a relay off the battery or alternator main leads, and use a small switch and wire to trigger it. The factory ammeter circuit cannot handle the amps for any sustained amount of time.

I'm sure the 90 amp alt is enough BUT you need the
larger wiring to handle the amps... the small(stock)
wiring will eat up the amps as in heat in the wiring

The fuel pump, water pump, and HHR fan are setup through relays that come off the battery to a 50 amp breaker and then to the relays where each relay powers a device. I used a three relay bundle from painless and they assured me they would handle the setup. I am not sure it's 10 gauge wire though to each device and is why i contacted Painless to verify.

The original wiring harness is still used though for the main car circuits including the ammeter wire that does run through the bulkhead etc and the gauge and then I would get back up to the starter relay.

I have no problem running the extra wire from the alternator directly to the battery but just wonder if i unhook the factory wire from the alternator will the regulator still work correctly on the exciter wires to turn it on?

So i guess give me the full synopsis of what I should do. I am guessing unhook the original heavy lead from the alternator and then just run the separate wire across with a fusible link?

madelectric.com has a whole write up on bypassing the amp gauge. Basically, take a large wire from the alternator output, through a fusible link, and to the starter relay.

Everything else should work the same (regulator wires), but your amp gauge won't work anymore.

That's a great article thanks!

I was having similar issues and ditched the amp meter years ago, soldered the wires together and installed a volt meter. I have batteries in the trunk and ran a welding cable to the statrer and #4 battery cable to a ford relay and a #6 from the relay to the alt. The stock alt. sucks so I installed a 60 amp denso and what a difference. Good luck...........

I rewired my buddies bracket car using info from the MADD electric articles. Used a 3 wire Alternator (high output)and all his wiring suggestions. The alternator keeps 14.5-14.8 volts everywhere when the car is running and the battery never goes down a lick.

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