Notices
1987 - 1996 F150 & Larger F-Series Trucks 1987 - 1996 Ford F-150, F-250, F-350 and larger pickups - including the 1997 heavy-duty F250/F350+ trucks

Speedometer problem

Thread Tools
 
Search this Thread
 
Old Dec 17, 2010 | 05:55 PM
  #1  
ravens fan's Avatar
ravens fan
Thread Starter
|
Senior User
Joined: Jun 2010
Posts: 408
Likes: 0
From: Curwensville,PA
Speedometer problem

my speedo has been acting very strange lately..... sometimes its reading at least 20 mph off, sometimes 10, but sometimes its right on,,,,, does anyone know what the problem could be? thanks
 
Reply
Old Dec 17, 2010 | 06:26 PM
  #2  
jim henderson's Avatar
jim henderson
Postmaster
20 Year Member
Joined: Mar 2001
Posts: 4,968
Likes: 3
From: So Cal
Tell us more about your truck. Year, model, tranny etc.

The speedo is driven one of several methods but without the above info we are just guessing.

Jim Henderson
 
Reply
Old Dec 17, 2010 | 09:28 PM
  #3  
ravens fan's Avatar
ravens fan
Thread Starter
|
Senior User
Joined: Jun 2010
Posts: 408
Likes: 0
From: Curwensville,PA
it is a 91 f-150 with the E4OD
 
Reply
Old Dec 18, 2010 | 09:07 AM
  #4  
raptor1971's Avatar
raptor1971
Senior User
Joined: Feb 2005
Posts: 165
Likes: 0
From: covington, ky
My speedo was jumping around. I changed the pickup sensor in the
rearend. It got worse, so I put the old one back in. I then disconnected
the rear abs box behind the glove compartment and it works know. I
do not care if I do not have rear abs. It locked the rear tires up when it was connected. Now I can use the cruise control again.
I know this is not the right way, but it worked for me.
My truck is a 1993 f150. If your speedo is the same setup you can try it.
You can do a search for speedo. There are other members with the same
problem.
 
Reply
Old Dec 18, 2010 | 09:37 AM
  #5  
Conanski's Avatar
Conanski
FTE Legend
15 Year Member
Photogenic
Photoriffic
Community Builder
Joined: Jun 2006
Posts: 31,930
Likes: 1,499
From: Ottawa, Ontario
That '91 likely has an all mechanical speedo and I'd say the speedo itself is on the way out, time to go shopping for a replacement cluster to pull the speedo out of.
 
Reply
Old Dec 18, 2010 | 02:13 PM
  #6  
xxshine's Avatar
xxshine
Senior User
Joined: Dec 2010
Posts: 295
Likes: 1
From: Ca.
Go digital w / a new 3 1/4 inch full face gauge. The speed sensor at the back of the trany should be O.K. It's just a magnet spinning around. I went all digital w / my 89.
 
Reply
Old Dec 18, 2010 | 03:02 PM
  #7  
ravens fan's Avatar
ravens fan
Thread Starter
|
Senior User
Joined: Jun 2010
Posts: 408
Likes: 0
From: Curwensville,PA
thanks guys i will prob have to start looking for a new speedo then
 
Reply
Old Dec 18, 2010 | 06:46 PM
  #8  
kd7ptn's Avatar
kd7ptn
New User
Joined: Dec 2010
Posts: 16
Likes: 0
I have had a problem with my mechanical speedometer jumping and not reading properly. I have seen this problem in the past growing up in my Dad's shop. Remember, here the speedometer works through a flex shaft that is connected to a gear at the tail end of the transmission. the flex shaft itself is dry and binding inside the the cable housing. disconnect the speedo from the instructment cluster and spray some lube down the shaft.
 
Reply
FTE Stories

Ford Trucks for Ford Truck Enthusiasts

story-0

Top 10 Fords at 2026 Carlisle Ford Nationals

 Joe Kucinski
story-1

3 Best / 3 Worst Parts of Modern Ford Ownership

 Brett Foote
story-2

10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches

 Pouria Savadkouei
story-3

Every 2026 Ford Engine Explained

 Brett Foote
story-4

10 Ugly Ford Trucks That We Still Kinda Love

 Joe Kucinski
story-5

10 Things Every Truck Owner NEEDS (2026 Edition)

 Michael S. Palmer
story-6

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

 Verdad Gallardo
story-7

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

 Joe Kucinski
story-8

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

 Brett Foote
story-9

Top 10 Ford Truck Tragedies

 Joe Kucinski
Old Dec 21, 2010 | 01:20 PM
  #9  
jim henderson's Avatar
jim henderson
Postmaster
20 Year Member
Joined: Mar 2001
Posts: 4,968
Likes: 3
From: So Cal
Maybe too late, but if you haven't bought anything yet...

I am not sure when the electronic speedos came in, my 94 F250 does have electronic. Don't know your model year.

Crawl under the truck for a minute or two and look at the top of the differential.

If you see a walnut size thingie on top with a couple of wires on it then you probably have an electronic speedo. Usually erratic speed reading with the electronic speedo are from a bad speed sensor(VSS). Replacing that and maybe checking the inside of the diff for metal fragments might be the cure. Sometimes when the VSS dies, junk gets spread on the ring that sends a signal to the VSS, so then you have to clean the inside of the diff. Usually this isn't needed since the VSS just dies or gets corroded connections.

If you have a mechanical speedo then I would suspect a sticky cable or bad speedo or gear in that order. The lube down the cable is a useful fix in many cases, cheaper and slightly easier than a new cable.

Good Luck,

Jim Henderson
 
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
MarauderV8
1997 - 2006 Expedition & Navigator
4
Mar 5, 2015 09:39 PM
GR$$N$
Excursion - King of SUVs
2
Nov 18, 2008 12:39 AM
JCastellaw
1966 - 1977 Early Broncos
29
Jan 6, 2008 02:37 AM
DanClarke
Ranchero & 1961 - 1967 Econoline
5
Nov 15, 2002 02:21 PM
AaronW
1973 - 1979 F-100 & Larger F-Series Trucks
3
Aug 23, 2001 11:45 PM




All times are GMT -5. The time now is 03:27 AM.

story-0
Top 10 Fords at 2026 Carlisle Ford Nationals

Slideshow: Top 10 Fords at 2026 Ford Nationals

By Joe Kucinski | 2026-06-09 11:10:08


VIEW MORE
story-1
3 Best / 3 Worst Parts of Modern Ford Ownership

Based on years of owning multiple modern Ford products.

By Brett Foote | 2026-06-09 10:53:36


VIEW MORE
story-2
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches

SPONSORED: From muddy boots to rain-soaked cargo, these upgrades address some of the most common frustrations Ford truck owners face every day.

By Pouria Savadkouei | 2026-06-08 18:50:34


VIEW MORE
story-3
Every 2026 Ford Engine Explained

Here's everything you need to know about every Ford engine available for the 2026 model year.

By Brett Foote | 2026-06-05 12:58:01


VIEW MORE
story-4
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-5
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-6
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-7
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-8
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-9
Top 10 Ford Truck Tragedies

Slideshow: Top 10 Ford truck tragedies.

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


VIEW MORE