Voltage Drop!!!

[Jonvhz]

I have a 1999 Toyota Tacoma running

2 10s 1600 watts

4 sylvester 6.5s

4 sylvester 8s

1800 watt taramps

Sundown sae 400.4

Big 4 upgrade

250 HO Singer alt

Duralast front bat

XSd3400 secondary bat

OfC 0 gauge wiring all around (multiple runs for the backup battery)





The voltage idles around 14.8 but at full tilt while driving it drops down to 12.4 and this only started happening recently. The voltage stays at that number whether I turn the volume down or even at a couple notches before my decks max allowable volume before distortion which is 28 (I usually only turn it to 25). If I turn off the truck and turn it back on it will go back to the 14.8 and idle they’re just fine until I turn it back up. I have checked the grounds for resistance and they are within the .2 range. I have also started to hear a slight squeal on startup maybe couple weeks prior coming from the alternator belt. I am wondering if I should start with possibly replacing that maybe going down a size to reduce any type of “overplay”?

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[Jonvhz]

Im thinking the belt is beginning to slip and therefore the alternator isn't able to constantly provide power at the rate it should be?? If anyone can confirm or has any other ideas id appreciate any type of feedback. thank you

 

[audiobaun 5,000+ posts]

Im not able to confirm 100% without being present. Yet, It does sound like it could be the possible Issue. if you have more than a 1/16" of play to where the tensioner move more than that while running then Id replace it. A new belt is fairly cheap to be replaced rather than most other components. Id also check your tensioner to see if it is actually setting in the proper location on the block. There should be a Tab on the tensioner that will set in the hole on the block so it stays positioned. Deff check that out. You can also give Singer a call to see what belt they recommend for that vehicle with the model # Alt you purchased from them.
I deff . check that tensioner to see of its setting in that groove on the block. Id even remove it to see if that impression for that block setting has broken off on the backside or not and even to see if its setting in there properly or not. That would be my first check. most tensioners are made of Alumin. Cast. I usually change mine every 2-4 years due to sealed bearings that I can grease.. You bdeff should be having that kind of voltage drop with the alt and batt/ect and power running

 

[Doxquzme Premium Member]

I have a 1999 Toyota Tacoma running

2 10s 1600 watts

4 sylvester 6.5s

4 sylvester 8s

1800 watt taramps

Sundown sae 400.4

Big 4 upgrade

250 HO Singer alt

Duralast front bat

XSd3400 secondary bat

OfC 0 gauge wiring all around (multiple runs for the backup battery)





The voltage idles around 14.8 but at full tilt while driving it drops down to 12.4 and this only started happening recently. The voltage stays at that number whether I turn the volume down or even at a couple notches before my decks max allowable volume before distortion which is 28 (I usually only turn it to 25). If I turn off the truck and turn it back on it will go back to the 14.8 and idle they’re just fine until I turn it back up. I have checked the grounds for resistance and they are within the .2 range. I have also started to hear a slight squeal on startup maybe couple weeks prior coming from the alternator belt. I am wondering if I should start with possibly replacing that maybe going down a size to reduce any type of “overplay”?

When you installed the HO alt, did you go down a half size or so on the belt?

 

[Old_Slapper]

I have a 1999 Toyota Tacoma running

2 10s 1600 watts

4 sylvester 6.5s

4 sylvester 8s

1800 watt taramps

Sundown sae 400.4

Big 4 upgrade

250 HO Singer alt

Duralast front bat

XSd3400 secondary bat

OfC 0 gauge wiring all around (multiple runs for the backup battery)





The voltage idles around 14.8 but at full tilt while driving it drops down to 12.4 and this only started happening recently. The voltage stays at that number whether I turn the volume down or even at a couple notches before my decks max allowable volume before distortion which is 28 (I usually only turn it to 25). If I turn off the truck and turn it back on it will go back to the 14.8 and idle they’re just fine until I turn it back up. I have checked the grounds for resistance and they are within the .2 range. I have also started to hear a slight squeal on startup maybe couple weeks prior coming from the alternator belt. I am wondering if I should start with possibly replacing that maybe going down a size to reduce any type of “overplay”?

I have seen this issue quite a few times. Hear are some things that caused it.

• Bad connection at the battery or battery grounding points, even where the battery is grounded to the engine. One of the cars, with this problem, didn't have a ground from the battery to the engine.
• Bad battery
• Bad alternator.

If the belt was slipping, you would hear it scream the entire time.

 

[Firewalker]

You mean 1/2 inch to 1 inch smaller belt. I started out with using a 1/2 inch smaller belt and settled on a 3/4 inch smaller belt when mine was all done.

Also it doesn't always scream when slipping. After close to 40 years working on cars I can say it doesn't always happen like that.

 

[some dude]

The belt might be slipping when the alternator gets loaded up and you wouldn't hear a thing because your audio is full tilt.

 

[audiobaun 5,000+ posts]

The belt might be slipping when the alternator gets loaded up and you wouldn't hear a thing because your audio is full tilt.

Very True to the Nature of it. !!! LOL !

 

[Firewalker]

Guess you guys haven't figured out that you can have someone in the car revving to 2k which is about what you will be driving at with it playing full tilt with the hood popped open while you listen and check out the belt for any sounds and that the belt tensioner is working properly.

 

[audiobaun 5,000+ posts]

Guess you guys haven't figured out that you can have someone in the car revving to 2k which is about what you will be driving at with it playing full tilt with the hood popped open while you listen and check out the belt for any sounds and that the belt tensioner is working properly.

Ive been able to do that by myself by using the throttle cable under the hood, but not absolutely knowing if its up to 2k or better? Ive even used a push-broomstick wedged on the seat and peddle by myself.

 

[spokey9]

Ive been able to do that by myself by using the throttle cable under the hood, but not absolutely knowing if its up to 2k or better? Ive even used a push-broomstick wedged on the seat and peddle by myself.

Both are better than dealing with a dumbazz cousin constantly asking "step on it now?"

 

[Firewalker]

Who uses a dumbazz cousin? Definitely not me! All of mine are in Italy or another state thank god,lol. Thankfully I have a neighbor who has a system or my dad who was doing this stuff before I was born and a machinist and jet engine mechanic to boot!

Or yeah using the throttle under the hood. After as many years as I've worked on engines building a 350 at 8 years old by myself. You get used to tuning by ear with engines and can come close to what the rpm's are.

 

[audiobaun 5,000+ posts]

Both are better than dealing with a dumbazz cousin constantly asking "step on it now?"

!!!