DC power dropped out - TCCoA Forums

 
LinkBack Thread Tools
post #1 of 11 (permalink) Old 05-18-2017, 07:30 AM Thread Starter
4th Gear Poster
 
Join Date: Feb 2013
Location: Fuquay-Varina, North Carolina
Posts: 204
DC power dropped out

This morning driving into work the cruise control just shut off. This happened twice and I noticed the second time the radio turned off and back on. The accelerator pedal poped up & the snap it made caught my attention.
The car never sputtered or shut down. It's like the power just dropped out real quick. I did a quick check before walking into work, battery is 12.4v; the connectors were tight with no corrosion. Looking for any ideas or experience. It's an aftermarket radio installed by the PO, so that's where I'm going to start checking.
Kidd-7 is offline  
post #2 of 11 (permalink) Old 05-18-2017, 04:26 PM
Seasoned PostWhore
 
S4gunn's Avatar
 
Join Date: Dec 2010
Location: SF, CA
Age: 38
Posts: 2,059
Garage
My guess is the alternator and/or voltage regulator on the back of the alternator is going out (so it's running only on battery power) or there's a loose connector/corrosion at the battery (so it was running on only alternator power).
I had something similar happen with an old commuter car. When the car is no longer providing as much power as needed for all the electrical accessories, stuff starts acting weird even if the car continues to run.

-g

My TCCOA iTrader Rating: (44 / 100% w/ 50+ transactions)
S4gunn is offline  
post #3 of 11 (permalink) Old 05-19-2017, 10:14 AM Thread Starter
4th Gear Poster
 
Join Date: Feb 2013
Location: Fuquay-Varina, North Carolina
Posts: 204
-g: Thanks for the insight. Battery terminals are clean and tight. I'll check out the alternator and do some voltage readings and check fuses. I pulled the radio last night and drove in w/o it. The wiring is all crimp connectors and not pretty. The cruise control would not work at all. I also noticed that the clock is dark, it did light up some for a few minutes, but went dark again.
Side note: Since I bought the car the volt gauge bounces when the blinker is on. I never really though much of it b/c the blinker indicators are on either side of the volt gauge, but maybe in fact that current draw is causing the voltage to dip.
Kidd-7 is offline  
post #4 of 11 (permalink) Old 05-19-2017, 11:14 AM
Seasoned PostWhore
 
S4gunn's Avatar
 
Join Date: Dec 2010
Location: SF, CA
Age: 38
Posts: 2,059
Garage
Quote:
Originally Posted by Kidd-7 View Post
-g: Thanks for the insight. Battery terminals are clean and tight. I'll check out the alternator and do some voltage readings and check fuses. I pulled the radio last night and drove in w/o it. The wiring is all crimp connectors and not pretty. The cruise control would not work at all. I also noticed that the clock is dark, it did light up some for a few minutes, but went dark again.
Side note: Since I bought the car the volt gauge bounces when the blinker is on. I never really though much of it b/c the blinker indicators are on either side of the volt gauge, but maybe in fact that current draw is causing the voltage to dip.
1) This all sounds like an alternator/voltage regulator issue to me.
2) most auto shops have a testbench in which they can test your alternator but keep in mind that the load on a testbench is "simulated" so a marginal alternator could pass the testbench but still fail in real world. These items do wear out.

Depending on how frugal you are, you can rebuild an alternator fairly cheap yourself (kits are on eBay). I've done it before and would do it again if you find the issue are voltage spikes (uneven voltage when measured at the alternator output.
Regards,
-g

My TCCOA iTrader Rating: (44 / 100% w/ 50+ transactions)
S4gunn is offline  
post #5 of 11 (permalink) Old 05-19-2017, 03:25 PM
No, Mr. Lemmywinks, No!!!

Moderator
 
Grog6's Avatar
 
Join Date: Jun 2005
Location: Harriman, TN
Age: 54
Posts: 8,285
Check the connections at the megafuse, below the outside fusebox; that's a common spot for problems.

Checking the voltage at the fusebox and tracing back while the blinker is making the voltage vary makes it easy to troubleshoot; when the voltage stops varying, the problem is between the last two points.

If it varies more than a volt at the battery itself, even with the engine off, your battery is wasted, or barely charged.

Charge the battery and check again; that's a sure sign of a cell that's slowly dying.

If charging the battery fixes the variation, the alternator isn't charging enough, and needs rebuilt; I've used "Victory Lap" kits from amazon with no issues. ~$20.

You may end up replacing the battery too, if the Alt has been undercharging for a long time.

Red '96 Cougar XR-7 240k mi. '02 4R70W, PST DS : '03 PI engine, 04 maf, 24lb injectors, 2.5" exhaust, '02 4r70w + Jmod, DirtyD0g TC + cooler + 3/8" lines, 255 walbro fp. Alpine system.
Black '96 Cougar XR-7 (Lazarus) 210k mi PI Intake, '02 4R70W, Jmod, PST DS, GrogTune, Konis, Mark LCA+Poly, racecougar Custom Engine Chain, and JL and racecougar Bracing.
Black '97 Tbird Limited Edition, '02 4R70W, 255 walbro, PST DS, PBR Brakes&SS lines, Toicko Blues & Springs, GrogTune.

I'm not Human enough to be human; but I'm trying to fit in, and I'm learning to fake it.

"Never said Hibbity..." - Brian Williams
Grog6 is offline  
post #6 of 11 (permalink) Old 05-19-2017, 03:38 PM Thread Starter
4th Gear Poster
 
Join Date: Feb 2013
Location: Fuquay-Varina, North Carolina
Posts: 204
Good advice thanks Grog6; didn't think of the mega fuse, but that thing is open to the elements. I'll run some voltage tests when I get home and see.
Kidd-7 is offline  
post #7 of 11 (permalink) Old 05-19-2017, 07:50 PM Thread Starter
4th Gear Poster
 
Join Date: Feb 2013
Location: Fuquay-Varina, North Carolina
Posts: 204
Checked the mega fuse, very slight green corrosion, but northing major.
Checked the voltage after work today. with the engine running I've only got 13.4v; Even reving the engine the voltage doesn’t climb. The battery voltage does drop about 2v when starting, so that battery is dying.
The battery is a 2 year old wally world batt. I may try swapping the battery with one of my other cars and see what happens.
Kidd-7 is offline  
post #8 of 11 (permalink) Old 05-20-2017, 12:20 PM
No, Mr. Lemmywinks, No!!!

Moderator
 
Grog6's Avatar
 
Join Date: Jun 2005
Location: Harriman, TN
Age: 54
Posts: 8,285
The limit of voltage drop on a battery during starting is to about about 8V, depending on what your engine is built to.

A 2V drop while turning the headlights on is a battery problem, not a 2V drop while starting.

I'd buy a rebuild kit for the alternator, and check the rest of the wiring; there's a problem somewhere.

Check the ground side out; I'd bet the heavy wire to the starter is going bad.

Look at the Sticky for the "Big Three" mod.

Red '96 Cougar XR-7 240k mi. '02 4R70W, PST DS : '03 PI engine, 04 maf, 24lb injectors, 2.5" exhaust, '02 4r70w + Jmod, DirtyD0g TC + cooler + 3/8" lines, 255 walbro fp. Alpine system.
Black '96 Cougar XR-7 (Lazarus) 210k mi PI Intake, '02 4R70W, Jmod, PST DS, GrogTune, Konis, Mark LCA+Poly, racecougar Custom Engine Chain, and JL and racecougar Bracing.
Black '97 Tbird Limited Edition, '02 4R70W, 255 walbro, PST DS, PBR Brakes&SS lines, Toicko Blues & Springs, GrogTune.

I'm not Human enough to be human; but I'm trying to fit in, and I'm learning to fake it.

"Never said Hibbity..." - Brian Williams
Grog6 is offline  
post #9 of 11 (permalink) Old 05-20-2017, 10:33 PM
Rob
Seasoned PostWhore
 
Rob's Avatar
 
Join Date: Jul 2002
Location: Hubbard, TX
Age: 35
Posts: 3,852
Send a message via AIM to Rob
You don't think maybe it's a cruise system problem rather than voltage supply? Perhaps it's a intermittent switch or failing cruise actuator? The reason I mention this is your only symptom is the cruise turning off, right?
Rob is offline  
post #10 of 11 (permalink) Old 05-21-2017, 06:50 PM
Seasoned PostWhore
 
S4gunn's Avatar
 
Join Date: Dec 2010
Location: SF, CA
Age: 38
Posts: 2,059
Garage
Quote:
Originally Posted by Rob View Post
You don't think maybe it's a cruise system problem rather than voltage supply? Perhaps it's a intermittent switch or failing cruise actuator? The reason I mention this is your only symptom is the cruise turning off, right?
He also mentioned the radio cutting out.
-g

My TCCOA iTrader Rating: (44 / 100% w/ 50+ transactions)
S4gunn is offline  
post #11 of 11 (permalink) Old 05-22-2017, 07:16 AM
Rob
Seasoned PostWhore
 
Rob's Avatar
 
Join Date: Jul 2002
Location: Hubbard, TX
Age: 35
Posts: 3,852
Send a message via AIM to Rob
Well damn, I missed that. Yeah I would also be suspicious of a big voltage drop/loss somewhere.
Rob is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the TCCoA Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome