Parasitic Drain

When I hook up an ammeter between the positive battery termal and the connector, I'm reading about a 4 amp drain. I pulled all the fuses one by one, but no difference. Does anybody have an idea what is normal? Alarm fuse is pulled, as I won't be using it. This seems really high to me, and I think my battery will go flat fairly quickly with that kind of draw on it.

Normal is much lower than 4 amps! You should be around 0.04-0.06 amps. There must be a circuit fuse that you missed (under the dash aftermarket radio, alarm, seats, etc). Or, something is wired directly (sans fuse).

Alternator? Are you positive it's wired correctly? Unplug it and see if the draw is still there

Thanks LT-1 and Spence, I checked the alternator, no go. Will look for more fuses, it"s really making me mad, getting close to driving it out of the garage this weekend.

I had a similar problem... was the FANs

Radiator fans? They are not on at all?

Ok, just realized I did not take off the power line from the alternator, will try that next. Power is applied to the white wire as per the GTO schematics. Charges fine when the enigine runs.

OK, removed the wire form he charging post, draw dropped down to 0.4A. This was a similar problem to what Dan J had, except mine is wired correctly, once hos was wwired like mine, his drain went away. So, is my alternator toast? I hope not, these GTO jobs are not cheap.

Sounds like a diode is gone in the alternator.

I'll take it out and test them, thanks Spence.

Ok, this is screwy, apply voltage to the charging lamp wire and the current drain goes down to 0.4A, just like the when the alternator charge wire is disconnected. I thought this just needed voltage when the engine is running to activate the charge circuit.

Final item on this, it appears there is some circuitry that responds to a voltage, if I just touch the brown lamp wire to +12v and remove it, the drain stops. So, I think I have put this one to bed.

That was quick. Nice job!

So is your alternator wired different from the other GTO alternators?

Hi Spense, no, it is the same. I found am 80 ohm short in the ignition side of the Porsche harness, this was causing the 0.4A current draw, the 4.0A current draw goes away when the brown wire from the alternator gets voltage. I've fixed the short, and now when I hook up the battery there is only an 86ma draw!

I did not measure any voltage on the blue Porache alternator wire, I will hook it up later today to the brown wire and see if the alternator charges. This is the last item for the engine harness. Next will be to charge the A.C and get that squared away.

OK, so, this has been a royal pain in the butt. After I fixed the short, things were looking up, dash gages came to life. However, I reported incorrectly about the brown wire turning off the current when connected to a positive voltage. I swapped batteries, and their terminals were reversed, so I was actually grounding it . So, when the engine is off, if I ground the brown alternator wire, my system is fine, no hot alternator, no battery drain. When I run the engine with the brown wire hooked up to the blue Porsche alternator wire, everything is happy, charges at 14.2 volts, within spec. So, what I am going to do is put a relay in, that grounds this wire when the engine is off, and connects it to the blue Porsche wire when the engine is running. I'll let you know how this works out. I realise this is a small subset of conversions out there, but if you want a beefier alternator, that does not need to be tied into the ECM, here you go! GTO alternators are 140 amos, and bolt in to the f-body accessory setup.

Do you have the idiot light bulb in the gauge cluster?

Yes, it has been fine for the last few weeks, with the engine off. Battery has maintained voltage. When I am back out there this weekend I will try it without grounding the idiot light wire with the engine off. I found some really good schematics of the regulator and diode setup. If it drains again, with the brown wire to the idiot light, and the white wire directly to plus 12, I have a voltage regulator or diode issue. The brown wire to the Porsche blue idiot light wire is perfect, that will work properly. This alternator is a nice upgrade for the 90-110A setups. The regulators and diodes are readily available and not expensive.

There is a bigger version of the truck alternators too (148amp?). I ended up with a 105amp truck alternator and the ECM is controlling the charge.

I thought the blue wire went to the idiot light. I just read it goes to the alternator light. Where on the dash is the alternator light?

At the very top of the voltmeter, when you first turn on the engine, you will see it light up red/orange depending on your perception of color. I call the alternator lights idiot lights.