Need HELP with a 99 tahoe 5.7

[mattp]

ok so i cant get my volts up any higher then 13.8={ I have 3 xs xp3000 in back one xs d3400 up front. and hade a dc power 270sp that would only charge at 13.8.. now i just put a dc power 300 spx in and nothing as changed, well the alt is charging at 14-14.1. when i called dc they said they should be charging at 14.8....I WISH

any body now what could be going on

oh and i have two guns of (+) and two runs of (-) from front to back...... idk im lost

[mattp]

Bump

[gredysra]

i thought i told u my story but more grounds help a lot or its the batts but i think a ground or two could help

[Loslam]

You can

1. Take off alternator and the bracket holding it, and clean off the metal contacts to engine block

2. Moar wire

3. Moar grounds to engine block or alternator/bracket

Edit:

When I put a new crate motor in my truck I took off the alt bracket and painted it black and it covered the metal where the bracket connects to engine block.

I removed it again and cleaned the paint off and got a nice clean metal finish and just that along with my current wiring jumped me from 14.6 to 14.9v

Edited April 27, 2012 by Loslam

[AMI CUSTOMS]

Here what you can do instead of listening to people who are just guessing at what to do, actually test for the problem....

Follow these steps

1. Get a DMM

2. disconnect your rear batteries, just have the one batt underhood

3. Put DMM to DC voltage

4. Read voltage at front battery- write down number or remember it(TRUCK OFF)

5. Keep POS probe from DMM on the battery

6. Put Neg probe from DMM to the alt case

7. Is voltage is different then reading direct at battery - Yes or NO

8. If step 7 is Yes - you have a ground problem add more grounds

9. If step 7 is No - you have a possible weak alt regulator or very bad connections

10. You are done report back here

This best I can give without actually being there and seeing what is going on, could be something simple you are overlooking.

[mattp]

Ok thanks guys I'll try this out tomorrow. And let you know what I find

[Iraggi Alternator]

Where are you checking voltage and at what rpm? I would check at the alternator and at 1500 rpm for starters

[mattp]

At alt. At idle

[mattp]

Here what you can do instead of listening to people who are just guessing at what to do, actually test for the problem....

Follow these steps

1. Get a DMM

2. disconnect your rear batteries, just have the one batt underhood

3. Put DMM to DC voltage

4. Read voltage at front battery- write down number or remember it(TRUCK OFF)

5. Keep POS probe from DMM on the battery

6. Put Neg probe from DMM to the alt case

7. Is voltage is different then reading direct at battery - Yes or NO

8. If step 7 is Yes - you have a ground problem add more grounds

9. If step 7 is No - you have a possible weak alt regulator or very bad connections

10. You are done report back here

This best I can give without actually being there and seeing what is going on, could be something simple you are overlooking.

Ok so I'm reading 12.56 at both

[Iraggi Alternator]

are you trying to get a higher resting voltage or just less of a drop? Im assuming your amp is 7500 watts... Your not gonna get much bettter voltge drop with one alternator and that much current draw. You can start off with higher voltage but it will fall to just about the same thing.