Speedometer very inaccurate, reads low... How to fix?

  • Thread starter Thread starter Cory Dunkle
  • Start date Start date
C

Cory Dunkle

My speedometer read about 5 MPH slow when I'm actually going 25-30 MPH and
about 10+ MPH slow when I'm actually going 60+ MPH. I got a speeding ticket
for 62 MPH in a 50 MPH zone a couple days ago because of this. I was doing
dead on the speed limit as far as my speedometer was reading, but allegedly
two cops got me with two radars at 62 MPH. In any case, how do I calibrate
the speedometer? Is it as simple as it is on old Fords where it's just a
little gear with different numbers of teeth that you cahnge on the
transmission/speedometer cable? Also, the speedometer needle bounces a bit
at slower speeds and steadies out to almost solid at higher speeds... Don't
know if that tells you anything or now. So if anyone could tell me how to
fix this I'd appreciate it.

Cory
 
Cory Dunkle said:
My speedometer read about 5 MPH slow when I'm actually going 25-30 MPH and
about 10+ MPH slow when I'm actually going 60+ MPH. I got a speeding ticket
for 62 MPH in a 50 MPH zone a couple days ago because of this. I was doing
dead on the speed limit as far as my speedometer was reading, but allegedly
two cops got me with two radars at 62 MPH. In any case, how do I calibrate
the speedometer? Is it as simple as it is on old Fords where it's just a
little gear with different numbers of teeth that you cahnge on the
transmission/speedometer cable? Also, the speedometer needle bounces a bit
at slower speeds and steadies out to almost solid at higher speeds... Don't
know if that tells you anything or now. So if anyone could tell me how to
fix this I'd appreciate it.
Click to expand...

Whoops... The car is an '86 Prelude 1.8 dual carb 5 speed.

Cory
 
Cory Dunkle said:
My speedometer read about 5 MPH slow when I'm actually going 25-30 MPH and
about 10+ MPH slow when I'm actually going 60+ MPH. I got a speeding ticket
for 62 MPH in a 50 MPH zone a couple days ago because of this. I was doing
dead on the speed limit as far as my speedometer was reading, but allegedly
two cops got me with two radars at 62 MPH. In any case, how do I calibrate
the speedometer? Is it as simple as it is on old Fords where it's just a
little gear with different numbers of teeth that you cahnge on the
transmission/speedometer cable? Also, the speedometer needle bounces a bit
at slower speeds and steadies out to almost solid at higher speeds... Don't
know if that tells you anything or now. So if anyone could tell me how to
fix this I'd appreciate it.
Click to expand...

Whoops... The car is an '86 Prelude 1.8 dual carb 5 speed.

Cory
 
Cory Dunkle said:
My speedometer read about 5 MPH slow when I'm actually going 25-30 MPH and
about 10+ MPH slow when I'm actually going 60+ MPH.
Click to expand...

Are you using the correct size tires?
 
Cory Dunkle said:
My speedometer read about 5 MPH slow when I'm actually going 25-30 MPH and
about 10+ MPH slow when I'm actually going 60+ MPH.
Click to expand...

Are you using the correct size tires?
 
Whoops... The car is an '86 Prelude 1.8 dual carb 5 speed.
Click to expand...

You don't mention whether you are using the standard size parameter
tires and rim on the car. A larger profile tire, or bigger diameter
rim would cause a higher speed reading.

As for the needle bouncing, from the Hondas I've been in (most late
80's early 90's) seem to do it. I think it's just a Honda thing. My
friend has a '84 Prelude XX 1.8 dual carb 5 speed as well, and his
speedometer reads 100km/h when he is actually doing 111km/h. His tires
are 195/60R14 on 14" rims which appear to be standard. It could also
just be a prelude thing. My Mitsubishi seems to be pretty accurate
with the speedo, I think it is about 3km/h out at 100km/h. My needle
doesn't seem to bounce either.

HTH,
Phil
 
Whoops... The car is an '86 Prelude 1.8 dual carb 5 speed.
Click to expand...

You don't mention whether you are using the standard size parameter
tires and rim on the car. A larger profile tire, or bigger diameter
rim would cause a higher speed reading.

As for the needle bouncing, from the Hondas I've been in (most late
80's early 90's) seem to do it. I think it's just a Honda thing. My
friend has a '84 Prelude XX 1.8 dual carb 5 speed as well, and his
speedometer reads 100km/h when he is actually doing 111km/h. His tires
are 195/60R14 on 14" rims which appear to be standard. It could also
just be a prelude thing. My Mitsubishi seems to be pretty accurate
with the speedo, I think it is about 3km/h out at 100km/h. My needle
doesn't seem to bounce either.

HTH,
Phil
 
Phillip Weston <[email protected]> decided to join the
conversation on 25 Oct 2003 with message
As for the needle bouncing, from the Hondas I've been in (most late
80's early 90's) seem to do it. I think it's just a Honda thing.
Click to expand...

The needle in my 91 civic bounced at low speed... until the cable broke ...
After replacing the cable.. it's as smooth as a baby butt. :)



--
-Chris

http://www.ChrisGarcia.com <- My Homepage
http://www.chrisgarcia.com/cars/ <- *NEW* My cars
http://www.chrisgarcia.com/dogs/ <- *Sort-of NEW* My dogs
http://starwars.chrisgarcia.com/ <- Centerpoint Station, the "ghost-town"
of the Star Wars Universe!
 
Phillip Weston <[email protected]> decided to join the
conversation on 25 Oct 2003 with message
As for the needle bouncing, from the Hondas I've been in (most late
80's early 90's) seem to do it. I think it's just a Honda thing.
Click to expand...

The needle in my 91 civic bounced at low speed... until the cable broke ...
After replacing the cable.. it's as smooth as a baby butt. :)



--
-Chris

http://www.ChrisGarcia.com <- My Homepage
http://www.chrisgarcia.com/cars/ <- *NEW* My cars
http://www.chrisgarcia.com/dogs/ <- *Sort-of NEW* My dogs
http://starwars.chrisgarcia.com/ <- Centerpoint Station, the "ghost-town"
of the Star Wars Universe!
 
Phillip Weston <[email protected]> decided to join the
conversation on 25 Oct 2003 with message


The needle in my 91 civic bounced at low speed... until the cable broke ...
After replacing the cable.. it's as smooth as a baby butt. :)
Click to expand...

That would make sense. The cable could deteriate prematurely.
 
Phillip Weston <[email protected]> decided to join the
conversation on 25 Oct 2003 with message


The needle in my 91 civic bounced at low speed... until the cable broke ...
After replacing the cable.. it's as smooth as a baby butt. :)
Click to expand...

That would make sense. The cable could deteriate prematurely.
 
Phillip Weston <[email protected]> decided to join the
conversation on 26 Oct 2003 with message
That would make sense. The cable could deteriate prematurely.
Click to expand...

Yeah.. It had bounced for the first 2 years i had the car (almost 3 years
ago).. and about 3 or 4 months before it broke, you could hear it rubbing
against something under the dash (like the housing for the cable had
broken open) at high speeds..

running without a speedometer is a very educational experience.. i had to
do it for about 3 or 4 months, since i couldn't afford to have it
replaced.. having to guess how fast you're going... i actually got VERY
good at it .. the city police have a "radar trailer" ... basically, it's
a radar gun on a trailer with a numerical display that tells you how fast
you're going.. i always nailed it within 3-4 mph..

--
-Chris

http://www.ChrisGarcia.com <- My Homepage
http://www.chrisgarcia.com/cars/ <- *NEW* My cars
http://www.chrisgarcia.com/dogs/ <- *Sort-of NEW* My dogs
http://starwars.chrisgarcia.com/ <- Centerpoint Station, the "ghost-
town" of the Star Wars Universe!
 
Phillip Weston <[email protected]> decided to join the
conversation on 26 Oct 2003 with message
That would make sense. The cable could deteriate prematurely.
Click to expand...

Yeah.. It had bounced for the first 2 years i had the car (almost 3 years
ago).. and about 3 or 4 months before it broke, you could hear it rubbing
against something under the dash (like the housing for the cable had
broken open) at high speeds..

running without a speedometer is a very educational experience.. i had to
do it for about 3 or 4 months, since i couldn't afford to have it
replaced.. having to guess how fast you're going... i actually got VERY
good at it .. the city police have a "radar trailer" ... basically, it's
a radar gun on a trailer with a numerical display that tells you how fast
you're going.. i always nailed it within 3-4 mph..

--
-Chris

http://www.ChrisGarcia.com <- My Homepage
http://www.chrisgarcia.com/cars/ <- *NEW* My cars
http://www.chrisgarcia.com/dogs/ <- *Sort-of NEW* My dogs
http://starwars.chrisgarcia.com/ <- Centerpoint Station, the "ghost-
town" of the Star Wars Universe!
 
The needle in my 91 civic bounced at low speed... until the cable broke ...
After replacing the cable.. it's as smooth as a baby butt. :)
Click to expand...

A bouncing baby's butt?
 
The needle in my 91 civic bounced at low speed... until the cable broke ...
After replacing the cable.. it's as smooth as a baby butt. :)
Click to expand...

A bouncing baby's butt?
 
Phillip Weston <[email protected]> decided to join the
conversation on 26 Oct 2003 with message


Yeah.. It had bounced for the first 2 years i had the car (almost 3 years
ago).. and about 3 or 4 months before it broke, you could hear it rubbing
against something under the dash (like the housing for the cable had
broken open) at high speeds..

running without a speedometer is a very educational experience.. i had to
do it for about 3 or 4 months, since i couldn't afford to have it
replaced.. having to guess how fast you're going... i actually got VERY
good at it .. the city police have a "radar trailer" ... basically, it's
a radar gun on a trailer with a numerical display that tells you how fast
you're going.. i always nailed it within 3-4 mph..
Click to expand...

Yeah we have them here too. Ours also show the fine you'd get if you
were travelling above the speed limit.
 
Phillip Weston <[email protected]> decided to join the
conversation on 26 Oct 2003 with message


Yeah.. It had bounced for the first 2 years i had the car (almost 3 years
ago).. and about 3 or 4 months before it broke, you could hear it rubbing
against something under the dash (like the housing for the cable had
broken open) at high speeds..

running without a speedometer is a very educational experience.. i had to
do it for about 3 or 4 months, since i couldn't afford to have it
replaced.. having to guess how fast you're going... i actually got VERY
good at it .. the city police have a "radar trailer" ... basically, it's
a radar gun on a trailer with a numerical display that tells you how fast
you're going.. i always nailed it within 3-4 mph..
Click to expand...

Yeah we have them here too. Ours also show the fine you'd get if you
were travelling above the speed limit.
 
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