speedometer stuck at 40 km

[tybuff]

hey

noticed today on my way to work that the speedometer is stuck at 40 km in my 85 cutlass supreme brougham.

It moves up fine from 40 km when accelerating, however it will not go any lower than 40 even when stopped.

I have recently installed a new amp and subwoofers in the car, so im not sure if this may be a voltage problem. Or something completely different.

Any help is appreciated.

 

[pontiacgp]

your speedo is mechanical so it's got to be a problem in your head unit...was your speedo making any unusual noise lately?

 

[tybuff]

no strange noises, all of a sudden

the speedo hasn't been acting up or anything. No strange noises.

the only thing that comes to mind is a front end problem that i have yet to solve. I'm getting ready to do a brake job this weekend and check everything out. Could these problems be linked by some sort of sensor in the wheel or anything?

as for the electronic root of it, i didn't think that would be the problem, as everything else in teh car is working fine since the stereo installation. This really has me stumped. Thanks for the help.

 

[pontiacgp]

the speedo head is driven by a cable that has a square shaft at the end to fit into the speedo gear located near the back of the transmission on the driver's side....the cable could not be the cause of the problem since the speedo does appear to the working...it's a problem in the speedo head so I would remove it and take a look at it. When it's removed the back of the speedo is open and the gears are clearly visible.

 

[tybuff]

thanks

thanks ill check that out this evening when i get off work. Thanks again for the insight.

Tyler

 

[Silent viewer]

i dont see any issue, just means you can go as fast as you want and you technically are not speeding! lol check the speedometer cable, i have heard of them going bad but still catching a little so it would half work.

 

[pontiacgp]

i dont see any issue, just means you can go as fast as you want and you technically are not speeding! lol check the speedometer cable, i have heard of them going bad but still catching a little so it would half work.

I don't think a defective cable would stop the speedo head from returning to 0....

 

[megaladon6]

ditto it sounds like something is blocking the needle from dropping.

 

[85 Cutlass Brougham]

It may be a problem with the return spring.

 

[Silent viewer]

i do not think that there is a spring that pulls it back but i could be wrong. i thought it was a weighted assembly type of thing in there..... i think i read th above wrong, it wont drop under 40? i was thinking it stopped at 40 and would not go any further....