Notices
6.0L Power Stroke Diesel 2003 - 2007 F250, F350 pickup and F350+ Cab Chassis, 2003 - 2005 Excursion and 2003 - 2009 van

Voltage readings??

Thread Tools
 
Search this Thread
 
Old Jun 30, 2016 | 08:41 AM
  #1  
redraider25's Avatar
redraider25
Thread Starter
|
New User
Joined: Sep 2014
Posts: 16
Likes: 0
From: Dallas
Voltage readings??

Quick question

My Insight CTS seems to be giving me inaccurate voltage readings when running. About 2 weeks ago I replaced the alternator on my truck due to low readings, had it tested and it was bad. Now my CTS is showing volts when running between 13.2 and 13.8 fairly consistantly. When I got home yesterday I parked the truck and I was showing 13.5v on the CTS. I got out my handy multimeter and tested the volts and the batteries and both read 14.1v. I have read that that due to loss in wiring and connectors that and gauge could read as much as +/- 5% which would make my CTS reading correct. Just makes me wonder what other readings on the CTS are inaccurate.

Any thoughts? Thanks in advance
 
Reply
Old Jun 30, 2016 | 09:06 AM
  #2  
TooManyToys.'s Avatar
TooManyToys.
Hotshot
Photogenic
Photoriffic
Shutterbug
Joined: Dec 2014
Posts: 17,829
Likes: 3,114
From: Jersey Shore
Loss in wiring and connections may not reflect the voltage at the batteries, but the readings may be reflective of the voltage at the components due to loss in wiring and connections.

There will always be some drop in voltage, but the goal is to reduce those drops by improving connections, cleaning any that haven't been touched in years. What is the voltage at the power port? Is it close to that at the batteries?
 
Reply
Old Jun 30, 2016 | 09:31 AM
  #3  
redraider25's Avatar
redraider25
Thread Starter
|
New User
Joined: Sep 2014
Posts: 16
Likes: 0
From: Dallas
Not sure what you mean by "power port"??
 
Reply
Old Jun 30, 2016 | 09:36 AM
  #4  
bobv60's Avatar
bobv60
Fleet Mechanic
Joined: May 2011
Posts: 1,866
Likes: 84
From: Rainier OR
Both my edge and my SCT Livewire read about a half volt Less that actual batt volts. The OBD port volts are often lower than the the battery, nothing to worry about.
 
Reply
Old Jun 30, 2016 | 09:39 AM
  #5  
redraider25's Avatar
redraider25
Thread Starter
|
New User
Joined: Sep 2014
Posts: 16
Likes: 0
From: Dallas
Kind of what I thought, just wanted to ask the question.

Any reason to worry about other readings with a CTS? None of the numbers seem out of the ordinary but just wondering?
 
Reply
Old Jun 30, 2016 | 09:40 AM
  #6  
texastech_diesel's Avatar
texastech_diesel
Token Redneck
15 Year Member
Liked
Loved
Community Favorite
Joined: Jun 2007
Posts: 9,337
Likes: 346
From: Breckenridge, TX
Club FTE Silver Member

Originally Posted by redraider25
Just makes me wonder what other readings on the CTS are inaccurate.
Does it really matter? There's no reading you can get from the PCM that has to be so accurate that the cumulative errors the components really matter. I bet most of the sending units themselves aren't better than +/-3%, they don't need to be just to make sure coolant at the t-stat housing is within 5* of 190*f. Consistency over the long term is more important than if a single PID is highly accurate.

Originally Posted by redraider25
Not sure what you mean by "power port"??
The 12V plugs on the dash, one is a cigarette lighter and the other just has a plastic plug stuck in it.
 
Reply
Old Jun 30, 2016 | 10:01 AM
  #7  
redraider25's Avatar
redraider25
Thread Starter
|
New User
Joined: Sep 2014
Posts: 16
Likes: 0
From: Dallas
I will check the power port at lunch just to settle my curiosity.
 
Reply
Old Jun 30, 2016 | 10:10 AM
  #8  
r2millers's Avatar
r2millers
Postmaster
Joined: Sep 2010
Posts: 3,472
Likes: 2
From: Southern Cal
Club FTE Silver Member

Wanna bet that your last alternator wasn't bad after all. You Must test not only at the batteries, but at the rear post on the alternator for the most accurate reading due to line resistance.
I see the same 13.5 v on my Dashboss through the OBD port, approx 1/2v diff.
Hope the forum can save you a few bucks in the future.
 
Reply
FTE Stories

Ford Trucks for Ford Truck Enthusiasts

story-0

10 Ugly Ford Trucks That We Still Kinda Love

 Joe Kucinski
story-1

10 Things Every Truck Owner NEEDS (2026 Edition)

 Michael S. Palmer
story-2

Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath

 Verdad Gallardo
story-3

Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer

 Joe Kucinski
story-4

2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)

 Brett Foote
story-5

Top 10 Ford Truck Tragedies

 Joe Kucinski
story-6

AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make

 Brett Foote
story-7

Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!

 Michael S. Palmer
story-8

Ford's 2001 Explorer Sportsman Concept Looks For a New Home

 Verdad Gallardo
story-9

10 Best Ford Truck Engines We Miss the Most!

 Joe Kucinski
Old Jun 30, 2016 | 10:23 AM
  #9  
redraider25's Avatar
redraider25
Thread Starter
|
New User
Joined: Sep 2014
Posts: 16
Likes: 0
From: Dallas
That is definitely a possibility. On the last alternator the CTS read low 12's and with engine running it read mid 12's at the battery. To compound everything my FICM was reading in the low 30's when driving so before I fixed the FICM I put an alternator on it. When the CTS was a little low on the Batt volts I started checking everything to hopefully prevent frying another FICM. Both batteries test good when cranking. Looks like I can check this off my to do list....for now...
 
Reply
Old Jun 30, 2016 | 10:28 AM
  #10  
TooManyToys.'s Avatar
TooManyToys.
Hotshot
Photogenic
Photoriffic
Shutterbug
Joined: Dec 2014
Posts: 17,829
Likes: 3,114
From: Jersey Shore
Work in progress, posted before. About as good as your going to get.

 
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
KDAVID1
6.0L Power Stroke Diesel
20
Feb 19, 2015 08:04 PM
bigred66
6.0L Power Stroke Diesel
21
Jan 21, 2013 09:51 PM
amdriven2liv
6.0L Power Stroke Diesel
25
Sep 8, 2011 02:34 PM
jetact
6.0L Power Stroke Diesel
5
Aug 13, 2010 01:56 PM
RangerTuff05
1973 - 1979 F-100 & Larger F-Series Trucks
6
Dec 30, 2008 01:29 AM




All times are GMT -5. The time now is 03:11 AM.

story-0
10 Ugly Ford Trucks That We Still Kinda Love

Slideshow: 10 ugly Ford trucks that we still kinda love.

By Joe Kucinski | 2026-06-03 09:51:16


VIEW MORE
story-1
10 Things Every Truck Owner NEEDS (2026 Edition)

Slideshow: the best gifts for dads & grads

By Michael S. Palmer | 2026-06-03 15:43:58


VIEW MORE
story-2
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath

Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.

By Verdad Gallardo | 2026-06-03 11:38:36


VIEW MORE
story-3
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer

Slideshow: 10 most expensive Ford trucks ever sold on Bring a Trailer.

By Joe Kucinski | 2026-05-27 16:24:34


VIEW MORE
story-4
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)

Here's everything that has changed for the latest model year.

By Brett Foote | 2026-05-27 16:17:28


VIEW MORE
story-5
Top 10 Ford Truck Tragedies

Slideshow: Top 10 Ford truck tragedies.

By Joe Kucinski | 2026-05-18 19:34:33


VIEW MORE
story-6
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make

And it might be even better than that.

By Brett Foote | 2026-05-18 19:26:42


VIEW MORE
story-7
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!

Slideshow: Does lowering an F-150 Lobo RUIN the ride quality?

By Michael S. Palmer | 2026-05-18 19:20:37


VIEW MORE
story-8
Ford's 2001 Explorer Sportsman Concept Looks For a New Home

Slideshow: Ford's bizarre fishing-themed Explorer concept has resurfaced after spending decades largely forgotten.

By Verdad Gallardo | 2026-05-12 18:07:46


VIEW MORE
story-9
10 Best Ford Truck Engines We Miss the Most!

Slideshow: The 10 best Ford truck engines we miss the most.

By Joe Kucinski | 2026-05-12 13:09:47


VIEW MORE