Those electrical woes -__-

[Det_Riot]

So maybe this is Karma for not informing @Prokiller ahead of time but I'm need if some serious help here. I've been chasing this for two days and I am at my wits ends trying to figure this out.

For those who don't know:

Car is a 94 gt, stock ecu, mild wire tuck with the fuse box relocated to underneath the back seat. Everything functioned fine after I did the work last year. Cluster is custom made, so I spliced the resister required in series with the two wires from the connector. Everything else is OEM

I just finished swappping in a new motor, everything runs, idles, etc, the car just doesn't want to charge.

I've gotten three alternators this weekend, all with the same result. I also replaced the resistor in the dash for shits n gigs.

With the connector plugged into the alternator, and key on, the ignition wire to the alternator is only getting 1.5V. From power distribution block, to the cluster, it's seeing a full 12v. As soon as it passes through the resistor, it drops to 1.5.

With the connector unplugged from thr alternator, it gives out voltage as youd expect. 12v up to the connector.

Both of these situations are key on, and with key off, the wire is dead as it should be.

I tried testing the system off my battery while the alternator was off the car. Everything holds at 12v until you ground the alternator case. Then it drops to 1.5v

@kbscobravert I know you just had wiring issues, any ideas?

I'm absolutely stumped and have no idea where to start

[ttocs]

how are you running the alternator ungrounded? 

[kbscobravert]

So maybe this is Karma for not informing @Prokiller ahead of time but I'm need if some serious help here. I've been chasing this for two days and I am at my wits ends trying to figure this out.

For those who don't know:

Car is a 94 gt, stock ecu, mild wire tuck with the fuse box relocated to underneath the back seat. Everything functioned fine after I did the work last year. Cluster is custom made, so I spliced the resister required in series with the two wires from the connector. Everything else is OEM

I just finished swappping in a new motor, everything runs, idles, etc, the car just doesn't want to charge.

I've gotten three alternators this weekend, all with the same result. I also replaced the resistor in the dash for shits n gigs.

With the connector plugged into the alternator, and key on, the ignition wire to the alternator is only getting 1.5V. From power distribution block, to the cluster, it's seeing a full 12v. As soon as it passes through the resistor, it drops to 1.5.

With the connector unplugged from thr alternator, it gives out voltage as youd expect. 12v up to the connector.

Both of these situations are key on, and with key off, the wire is dead as it should be.

I tried testing the system off my battery while the alternator was off the car. Everything holds at 12v until you ground the alternator case. Then it drops to 1.5v

@kbscobravert I know you just had wiring issues, any ideas?

I'm absolutely stumped and have no idea where to start

If you want my solution. I would stop going through the cluster and dash wiring for the command signal.

Run a relay that is triggered by key on/run.

I just had to do this exact same thing. Except I just used the power out side of my fuel pump relay to trigger the alternator on. Fuel pump on - alternator on. The alternator shouldn't draw any amps to speak of.

[Det_Riot]

how are you running the alternator ungrounded? 

 

It wasnt on the car running, It was basically bench testing to verify 12v at the switched terminal

 

If you want my solution. I would stop going through the cluster and dash wiring for the command signal.

Run a relay that is triggered by key on/run.

I just had to do this exact same thing. Except I just used the power out side of my fuel pump relay to trigger the alternator on. Fuel pump on - alternator on. The alternator shouldn't draw any amps to speak of.

 

hmmmm worth a shot. does the system not really need the resistance from the dash to function? @Prokiller just had that same issue. I guess I'm confused that if you're wiring in a relay, you're still going to just be getting 12v without the resistance inline?

[ttocs]

the chassis of the alt is grounded to the block is why I am confused when you say its good till you ground the alt.  What wattage resistors are you using I the dash and did you test the old one to see if its ok?

[Det_Riot]

the chassis of the alt is grounded to the block is why I am confused when you say its good till you ground the alt. What wattage resistors are you using I the dash and did you test the old one to see if its ok?

Because I tested the alternator and resistor off the car. I used another 510 ohm resistor off the back if a spare cluster. Tested out at 510ohms on the money

[Prokiller]

the karma is only for busting my chops about it after the fact Bryan.  don't think i blame you for anything.  I slept on it and i still can't think of any reason why if you have everything connected and wired in with the resistor that it shouldn't be charging.

[Det_Riot]

Here's a plot test. Everything works today

[Zach]

It's charging fine now?

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[Blackmage]

wiring gremlins doing their best work!