Toyota Tundra Discussion Forum banner

1 - 8 of 8 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter #1
Ok guys I need some help here,

2008 SR5 Dbl Cab, 130k, only electrical aftermarket mod is H/U installed over a year ago.

Driving truck and motor starts to stall when not under load (coasting or stopped), take it to repair place where we've had my wifes car worked on and they say the alternator is going bad and needs to be replaced.
I buy an OEM alternator from Toyota (ouch.) and do it myself. Get everything back together and same issue is still occurring, batter slowly looses charge and truck will start to die. Take the battery to the store I bought it from (advance auto) they test it and say the battery is fine.

The battery gauge slowly starts going down after I drive it for about 5 mins but the needle will jump back up when I accelerate.

Any ideas? Could the battery be dying and the store just not be seeing it on their tester? Anyone ever had an alternator from Toyota be bad when first installed?

Thanks in advance for any ideas or help. I NEED my truck.
 

·
Registered
Joined
·
7,071 Posts
Check all your electrical connections. There's either a short, or you have a connection that isn't tight. Take the aftermarket radio out completely and see if the trouble goes away...most likely its in your aftermarket radio something isn't hooked up properly seems this is extremely common with people who install stuff there's always something that goes wrong it seems like LOL.
 

·
Premium Member
Joined
·
1,004 Posts
Could the battery be dying and the store just not be seeing it on their tester?
A bad battery is unlikely to cause the symptoms you describe. It would have to have an internal short to draw more current than the alternator can produce. Rare, but I have seen that once before.
When you hook up the terminals to the battery, is there an arc welder type spark, or is it just a small spark?
Do the battery cables get hot to the touch?
Does the battery die if the truck just sits there or does it have to be driven for the battery to discharge?

Anyone ever had an alternator from Toyota be bad when first installed?
Unfortunately, yes.

Ok guys I need some help here
Do you own a multimeter and know how to use it? If yes, I should be able to help you figure your problem out. If no, you could buy one for about $30, much less than what you paid for the alternator (that you may or may not have needed).

Even without a multimeter, first things to check are:

5 Amp fuse called "ALT-S" in the fuse box on driver side under the hood.
7.5 Amp fuse called "LH-IG" in the fuse box on driver side beside the steering column inside the truck.
140 Amp (or 180 Amp) large fuse called "ALT" in the fuse box on driver side under the hood.

If those are all fine, get a multimeter to narrow down the problem. Good luck.

Viktor
 
  • Like
Reactions: RIjon

·
Banned
Joined
·
5,396 Posts
It is most likely the 180a alternator fuse. Take a set of jumper cables and connect one end to the + on the battery and the other end to the + on the alt. This will tell you if it is the fuse or not
 

·
Registered
Joined
·
6 Posts
Discussion Starter #5
Alright update time, checked the fuses and they were fine.

Called a couple mechanic buddies and tried some things. Come to find out my throttle body was so damn dirty it wasn't shutting all the way so my truck was couldn't reset itself after the battery had been off. Basically it was falling into limp mode. Cleaned it up and no more problems.

Appreciate everyone's imput and ideas as this has definitely been a learning experience for me.
 

·
Registered
Joined
·
2,967 Posts
Thanks for the follow-up on this.
 

·
Registered
Joined
·
1 Posts
This post just saved me! Put in a cheap HU with Bluetooth so I can enjoy my stories and blast Moana with the kids. Reconnected everything and my Grey Goliath (08 DC SR5 5.7) was doing the limp mode. I went through checking all the radio shite, battery testing, even got a remanufactured 150amp alternator and put it in myself and same limp mode. Bout to pull my hair out and found this post, wiped the crud off my throttle body and It evened out. Thanks man!
 
1 - 8 of 8 Posts
Top