Charging question on my 3.4

[cardana24]

I have a 3.4 engine from a 94 camaro in my Jeep Cherokee. Just last night I put in a volt meter because I thought that I may have a charging issue. So I watched the volt meter on my 20 mile drive to work this morning. When I cranked the jeep the volt meter showed 13.8ish volts. When I would push the gas the voltage would drop slightly then return to the original voltage. After the jeep warmed up at idle it was running around 13 volts. When I turned the heat on the voltage dropped down to around 11 volts then came back up to 12volts and stayed around that much the whole time I was driving. When I turn the light on the voltagage would drop to around 9 then come back up to 12. Are these the reading I should seeing? I figured when I reved the engine the volts would go up, as opposed to going down, also I did not think it would run ~12 volts with the heat on. I plan on having my charging system checked today, but I would like to see what you guys think.

[bszopi]

Sounds like the regulator inside the alternator isn't working properly. When driving, the alt should be putting out between 13.5-14.1v. And yes, when you rev the engine, the voltage should go up or remain at a higher level.

[cardana24]

Sounds like the regulator inside the alternator isn't working properly. When driving, the alt should be putting out between 13.5-14.1v. And yes, when you rev the engine, the voltage should go up or remain at a higher level.

Do you think a sipmple charging system check at Advanced Auto would be able to detect that?

[robertisaar]

if it doesn't, i wouldn't trust their machines anyway. you quite obviously have a charging issue, if they say the alt is good, their machine is junk.

[cardana24]

They said it was fine, said under no load it showed 14.06V, under load is showed 13.89V. Who knows.

[Ed_Mc.]

Check the voltage right off the alternator lead then check voltage off the battery (+) terminal. If there is a significant difference between these (2) reading you've got some sort of wiring problem.

Check all your grounds, also many rigs have a fusible link connection between alt and the rest of the system; if the fusible link wire is burnt out or broken, you'll get a very high output out of your alternator but no charge effect to the rest of the system.

One easy way to check for this is to run a jumper between the output wire of the alt, over to the battery (+) terminal. Then see if battery voltage increases with rpm.

If it does, most likely that fusible link is bad.

Word of caution when running this jumper, take special care to observe proper polarity, if you don't you're gonna burn something out!

HTH...........ed

[cardana24]

Check the voltage right off the alternator lead then check voltage off the battery (+) terminal. If there is a significant difference between these (2) reading you've got some sort of wiring problem.

Check all your grounds, also many rigs have a fusible link connection between alt and the rest of the system; if the fusible link wire is burnt out or broken, you'll get a very high output out of your alternator but no charge effect to the rest of the system.

One easy way to check for this is to run a jumper between the output wire of the alt, over to the battery (+) terminal. Then see if battery voltage increases with rpm.

If it does, most likely that fusible link is bad.

Word of caution when running this jumper, take special care to observe proper polarity, if you don't you're gonna burn something out!

HTH...........ed

Thanks for the advice I will check on that later. What would you consider a
"significant difference" in voltage, when checking the output on the alternator and battery?