Gunny Highway

iTrader: (1)

OK guys, I just got done doing a motor swap (305 TBI -->350 TBI), but now the voltage is reading low. We think this is what is causing the car to sometimes to start choking after reving her up real quickly. ??? She starts up perfectly, just so you know.

Anyways, she's reading between 8-10 volts.

Of course after 2 months of being apart the battery was low, but we recharged that. Also, we had the alternator checked out, and 2 out of 4 places said it was ok. The alternator is a 1 year old AC Delco one FWIW.

My father (who help me put it in) thinks that it's a wiring issue, but I'm still skeptical about the alternator. Any ideas guys?

Thanks.

Trickster

It sounds like it is 50 - 50, what did the other 2 out of 4 places say about it?

IROCaholic

Get the car started and let it run for a second then get a screw driver and touch the round piece of metal on the back of the alternator that spins while the alternator moves. Be sure not high wire on the back of the alternator or youll short it out If you feel it pulling the screw driver like its magnitised then your alt is charging if not its not. I bet its the alt. if anyone says its not working and no one said the batt is bad then I would blame the alternator.

Vader

Gunny,

Are you reading voltage via the dash-mounted meter, or verifying a low voltage condition with a separate handheld meter?

If the voltage is truly low, check it directly at the alternator output stud to a known good ground, like the alternator case. If the voltage is normal (13.8-14.5VDC), read the voltage between the alternator case and battery negative post, and then to the chassis ground. If there is more than 0.2VDC, you have a ground connection problem. Ideally, there should be zero volts.

Do the same test between the alternator output stud and the battery positive terminal. Then check between the output stud and a chassis power node, like the fusible link connetor at the RR of the engine bay. Again, more than 0.2VDC indicates a connection problem. Again, zero volts is preferable.

If the alternator is not generating 13.8-14.5VDC at the stud, you may have an alternator or regulator problem. You can briefly test teh maximum alternator output by shorting the test tab in the rear case of the alternator.



Grounding that tab just long enough to get a voltage reading is all that's necessary. The alternator should output upwards of 17VDC for this test, and you'll likely set a DTC as a result (code 53). Not a problem. Just clear the code if it sets. If the alternator does not develop 17VDC+, you either have a failing battery (shorting cell) that is holding voltage down or a failing alternator.

If the alternator does produce the higher voltage when the test tab is shorted, start looking at the regulator connections, regulator itself, and ignition switch and the resistance wire from the seitch to the alternator field connector.

Gunny Highway

iTrader: (1)

Gunny Dad here...

Took alt to Auto Zone...good.
Took alt to Pep Clowns...bad.
Took alt to different Auto Zone...bad.
Took alt to Advanced Auto...good.

They all used the same brand tester and looked like the same model as well.

Battery was low. Had it charged.

Couldn't find my VOM so I could test further.
Either I have way too many tools...
Or...
Everything is where it should not be.
Either way, a Saturday and a case of cold beer should help me get orgainzed, again.

Anywho, I think the big red wire from the alt is in the harness going towards the starter. It should be going to the junction block that is along side the battery and attached to the radiator support frame.

I plan to look at it later today.
But I have to check my cold beer supply first.

Gunny Highway

iTrader: (1)

Gunny Dad hear, again...

Update.

Thanks to those who helped in this issue.

The problem was a wire was on the wrong screw stud. The big red wire from the alternator was attached with the purple wire on the starter solenoid. But, hey, it fit like it belonged there. It was supposed to attach to the junction block that is near the battery. But, hey, it fit like it belonged there too. OK, i'm up to 1 minor error.

Now that it is attached where it belongs, the battery and alternator are working like a team. Yea!

Still have TBI problems, those are posted in that arena.

Thanks again for ya'lls help.