Bad Speedo, Speedo cable, or both?
Thread Starter
Instructor
Joined: Sep 2003
Posts: 160
Likes: 30
From: Auburn WA
Bad Speedo, Speedo cable, or both?
I'm a little sad that the Speedo on my Vette has quit - and not because I cant tell how fast I'm going...
You see - all old cars have their "quirks" since I’ve own the car the speedo never worked well when it was cold - really. It would bounce around from 0-20 when I was only going about ten. After about 30 though it read accurately and the bouncing was less obvious when the car was warm. It was just one of those odd things that I sort of liked......but alas, all good quirks must come to an end.
At some point (the car had sat for about a year - I know, shame on me) something went wrong (or perhaps more wrong). here is what happens now:
- The speedo does not read accurately at all, at any speed
- The needle bounces around - swinging wildly in a general 40 HPH arc - so say from 40MPH to 80MPH. - I'm probably doing 45-ish
-The arc will decrease and increase as I go faster and slower - It gets really funny with on-ramp acceleration, apparently I hit over 100MPH.
- Neither the odometer or trip counter operate.
Its clear that faster and slower speeds have a direct effect on the speedo - so the cable cant be broken, but I suppose it could be bound up or something and so working in jerking motions, but then I'd expect the Odometer and trip counter to work, at least somewhat, but they don’t move at all. If nothing worked, I’d assume the cable was broken and get another - but its alittle confusing and I cant decide if its the cable or the speedo, or both.
Thoughts? (car is a 1978)
Thanks!
You see - all old cars have their "quirks" since I’ve own the car the speedo never worked well when it was cold - really. It would bounce around from 0-20 when I was only going about ten. After about 30 though it read accurately and the bouncing was less obvious when the car was warm. It was just one of those odd things that I sort of liked......but alas, all good quirks must come to an end.
At some point (the car had sat for about a year - I know, shame on me) something went wrong (or perhaps more wrong). here is what happens now:
- The speedo does not read accurately at all, at any speed
- The needle bounces around - swinging wildly in a general 40 HPH arc - so say from 40MPH to 80MPH. - I'm probably doing 45-ish
-The arc will decrease and increase as I go faster and slower - It gets really funny with on-ramp acceleration, apparently I hit over 100MPH.
- Neither the odometer or trip counter operate.
Its clear that faster and slower speeds have a direct effect on the speedo - so the cable cant be broken, but I suppose it could be bound up or something and so working in jerking motions, but then I'd expect the Odometer and trip counter to work, at least somewhat, but they don’t move at all. If nothing worked, I’d assume the cable was broken and get another - but its alittle confusing and I cant decide if its the cable or the speedo, or both.
Thoughts? (car is a 1978)
Thanks!
Instructor
Joined: Dec 2006
Posts: 105
Likes: 0
From: biloxi mississippi
I'm a little sad that the Speedo on my Vette has quit - and not because I cant tell how fast I'm going...
You see - all old cars have their "quirks" since I’ve own the car the speedo never worked well when it was cold - really. It would bounce around from 0-20 when I was only going about ten. After about 30 though it read accurately and the bouncing was less obvious when the car was warm. It was just one of those odd things that I sort of liked......but alas, all good quirks must come to an end.
At some point (the car had sat for about a year - I know, shame on me) something went wrong (or perhaps more wrong). here is what happens now:
- The speedo does not read accurately at all, at any speed
- The needle bounces around - swinging wildly in a general 40 HPH arc - so say from 40MPH to 80MPH. - I'm probably doing 45-ish
-The arc will decrease and increase as I go faster and slower - It gets really funny with on-ramp acceleration, apparently I hit over 100MPH.
- Neither the odometer or trip counter operate.
Its clear that faster and slower speeds have a direct effect on the speedo - so the cable cant be broken, but I suppose it could be bound up or something and so working in jerking motions, but then I'd expect the Odometer and trip counter to work, at least somewhat, but they don’t move at all. If nothing worked, I’d assume the cable was broken and get another - but its alittle confusing and I cant decide if its the cable or the speedo, or both.
Thoughts? (car is a 1978)
Thanks!
You see - all old cars have their "quirks" since I’ve own the car the speedo never worked well when it was cold - really. It would bounce around from 0-20 when I was only going about ten. After about 30 though it read accurately and the bouncing was less obvious when the car was warm. It was just one of those odd things that I sort of liked......but alas, all good quirks must come to an end.
At some point (the car had sat for about a year - I know, shame on me) something went wrong (or perhaps more wrong). here is what happens now:
- The speedo does not read accurately at all, at any speed
- The needle bounces around - swinging wildly in a general 40 HPH arc - so say from 40MPH to 80MPH. - I'm probably doing 45-ish
-The arc will decrease and increase as I go faster and slower - It gets really funny with on-ramp acceleration, apparently I hit over 100MPH.
- Neither the odometer or trip counter operate.
Its clear that faster and slower speeds have a direct effect on the speedo - so the cable cant be broken, but I suppose it could be bound up or something and so working in jerking motions, but then I'd expect the Odometer and trip counter to work, at least somewhat, but they don’t move at all. If nothing worked, I’d assume the cable was broken and get another - but its alittle confusing and I cant decide if its the cable or the speedo, or both.
Thoughts? (car is a 1978)
Thanks!
Thread Starter
Instructor
Joined: Sep 2003
Posts: 160
Likes: 30
From: Auburn WA
my 78 did the same thing last year- it was my cable - cable was not easily removed as it was coming unwound in the center- if you have a verable speed drill and a friend you could take the cable off at the tranny , attatch it to the drill and let the friend watch the speedo (if its a really good friend maybe he can do the drill while you watch.
Le Mans Master
Joined: Jul 2000
Posts: 6,664
Likes: 162
From: columbia city in
on the tips of your speedo cable are square.some times they have little metal square tips on them.these round off as do the plastic that they go into .this can cause bouncing of the speedo or a bad reading .or you cable has broken .on most corvettes what i check is the cable from the trans to the cruze transducer. the transducer binds up and breaks the cable .check and lube all cables .
