Alternator?
Thread Starter
|
Cross-Country
Joined: Jul 2003
Posts: 95
Likes: 2
Alternator?
2004 Excusion LTD, 6.0 PSD. Driving home the radio head goes blank/comes back several times. Cluster gauges die/come back. Back home truck won't start after shutdown, lots of flashing dash lights/clicking etc.
Batteries read 10.1V after shutdown. Reconnected the batteries and jump started. Then the votages across the poles of both batteries and alternator to ground are ~14V, and then the goofiness starts again. Now the voltages at the batteries and alternator have dropped to 10V, engine running.
Bad alternator? Is the voltage regulator internal to the alternator?
Batteries read 10.1V after shutdown. Reconnected the batteries and jump started. Then the votages across the poles of both batteries and alternator to ground are ~14V, and then the goofiness starts again. Now the voltages at the batteries and alternator have dropped to 10V, engine running.
Bad alternator? Is the voltage regulator internal to the alternator?
Certified Thread Hijacker
Joined: Aug 2001
Posts: 14,441
Likes: 59
Test the voltage at the power terminal on the alternator.
Back probe the "A" circuit on the alternator plug, engine off and engine on. Both readings should read the same as battery voltage at the battery terminals.
Sounds like corroded wiring or terminals to me.
Best thing to do is to charge both batteries and then have them load tested seperately and also the alternator tested.
Josh
Back probe the "A" circuit on the alternator plug, engine off and engine on. Both readings should read the same as battery voltage at the battery terminals.
Sounds like corroded wiring or terminals to me.
Best thing to do is to charge both batteries and then have them load tested seperately and also the alternator tested.
Josh
Postmaster
Joined: Jan 2005
Posts: 4,424
Likes: 12
From: BC Canada
Likely bad alternator but best way to test is to load test at store. What is charging voltage ad the big red cable after startup and about 10 minutes after start. Should be 14.4 to 14.8 charging. Batteries should be above 13.0 when idling after batteries charged up. 10.1 definitely a problem. You may also have a bad battery, replace in pairs, after charge they should read 12.6 to 12.8 volts, better still measure specific gravity of each cell. Should be greater than 1.025, preferably all 1.030 for each cell. Any one cell off from the others you have a bad cell, need two new batteries.
Hotshot
Joined: Apr 2010
Posts: 19,055
Likes: 235
From: Saratoga Springs,UT
I had very similar problems when my alt died
When the Key was in On position or Cranking Major power drain All gauges went crazy even the clicking sounds
But I could NOT get it to start even with a Jump start
Charge the Batteries and Unhook the alternator and start it and see if it runs Normal with the Alternator unhooked if it runs ok this way you likely found the Culprit
It could be caused by lots of things though so I would investigate more before alternator replacement
When the Key was in On position or Cranking Major power drain All gauges went crazy even the clicking sounds
But I could NOT get it to start even with a Jump start
Charge the Batteries and Unhook the alternator and start it and see if it runs Normal with the Alternator unhooked if it runs ok this way you likely found the Culprit
It could be caused by lots of things though so I would investigate more before alternator replacement
Logistics Pro
Joined: Feb 2005
Posts: 3,952
Likes: 117
From: Upper Left Coast
howdy,
Any time I have intermittent voltage readings, etc, I start with ground (strap) , battery and other connections related to power distribution before assuming an alternator is bad.
You still driving a HRK?
Any time I have intermittent voltage readings, etc, I start with ground (strap) , battery and other connections related to power distribution before assuming an alternator is bad.
You still driving a HRK?
Former Vendor
Joined: Feb 2010
Posts: 1,803
Likes: 4
Completely concur with the consensus here. Check (cleanup) your grounds and see if the issue resolves itself. Of course, you can (and really should) just pull the alternator to have it bench tested.
If it's shot, the general and common consensus here is that the stock alternator is just too small for the application. We can hook you up with a DC Power alternator that is a huge improvement over anything that came off of the factory floor, saving you a couple nickels off of the price on the DC Power site in the process.
Check those grounds first, though. Easy and free fixes are always preferred.
If it's shot, the general and common consensus here is that the stock alternator is just too small for the application. We can hook you up with a DC Power alternator that is a huge improvement over anything that came off of the factory floor, saving you a couple nickels off of the price on the DC Power site in the process.
Check those grounds first, though. Easy and free fixes are always preferred.
Trending Topics
Hotshot
Joined: Apr 2010
Posts: 19,055
Likes: 235
From: Saratoga Springs,UT
This is Excellent Advice^^^^
power problems can do weird stuff
And I can confirm what FICMREPAIR.COM is saying about the DC Alternator huge improvement over OEM
Only read about a couple DC Alts failing compared to some chain parts store alts Iv seen guys go thru 3 alternators before they get 1 that works and its sad but that's kinda common. Or they have to change it once a Year But its fine as long as you watch it and stay on top of it. Its hard to beat the chain store Lifetime warrantee
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Top 10 Ford Trucks Coming to Mecum Indy 2026
Brett Foote
5 Best / 5 Worst Ford Truck Wheels of All Time
Joe Kucinski
Ford Super Duty: 5 Things Owners LOVE, 5 Things They LOATHE!
Joe Kucinski
Every 2026 Ford Truck Engine RANKED from WORST to FIRST!
Michael S. Palmer
The Best F-150 Deal of Every Trim Level (XL through Raptor)
Joe Kucinski
Thread
Thread Starter
Forum
Replies
Last Post
Coccyx
Pre-Power Stroke Diesel (7.3L IDI & 6.9L)
14
Nov 15, 2017 11:10 AM