Speedometer Tech??

[Black1986Beast]

Hey..Well purchased my GN with the aftermarket 145mph speedo already installed..Well the problem is that it doesn't go past 40mph..and I dont even think it reads correctly.
I have the Scanmaster 2.1 and That and the Speedo read the same mph up to 40..but the problem is I KNOW I'm going faster than I actually am..and since I get my license in a week, I dont want any speeding tickets, especially for a stupid reason such as this..
Does anyone know what I can do or how to fix it?
Thanks

 

[cturboaddict]

Is it digital or anaolg

is this the digital or the analog speedo?????????????

 

[Wht87T]

I think Dennis Kirban can take care of that for you. kirbanperformance.com

 

[Steve Wood]

Most larger towns have a speedometer repair place....

 

[Black1986Beast]

Re: Is it digital or anaolg

Originally posted by cturboaddict
is this the digital or the analog speedo?????????????

Analog--I don't know of any places around here that are known for fixing speedometers...but maybe I should start looking!
Unless someone knows what my problem might be and how I could possibly fix it myself..My friend thinks it may be the speed sensor or something..and it must be something like that since the scanmaster is reading the same MPH as the speedo up to 40MPH..but we're definately not going as fast as we are..I'd say it's prolly off by about 10MPH

 

[dpok69]

Hey!

I have the same exact stupid problem with my digital dash. If i go a 100mph it will read 50. i have never seen it pass 52mph. And the SM reads the same mph.

This could also be screwing with our fuel parameters that the ECM controls. I have poor gas economy,even though my car is in tune.

I would have just replaced my VSS sensor, which i think is behind the radio, but my freind pointed something out to me in the engine compartment.

There is this weird square coupling connecting a black cable i think that heads down to the tranny (speed reducer gears?) Maybe this coupling is there to maybe lower odometer reading to keep up resale value of car from previous owner?

Anywayz my friend told me to fix that with one cable running down to the tranny i think.

So check if you also have this coupling (grey box with black cable), if not it is probably the VSS sensor.

 

[blackbuick87]

The VSS sensor is behind the speedo I believe, not behind the radio. To find the cable just look along the drivers side under the hood next to the master cylinder. If it is directly coupled to the tranny cable there is no reducer.

 

[dpok69]

Would the reducer lower the mph figure?

 

[cturboaddict]

VSS

the vss is connected to the speedo with one screw and is connected to a green square box ( the vss buffer) that is behind the radio. Just to let you know. you would have to take out the dash and the radio to remove it. But i think the speedo reading has nothing to do with the analog dash just the digital. my dash reads blank but i just cant figure it out. every now and then it works. but you have to remember that my vehicle is a 85 s-10 with an 85 regal t-type motor in it. i put the digital dash in it and it worked for a day or so but since then nothing with the exception of maybe two times it worked for and hour or so.

 

[dpok69]

On the '87 model, the ground for the digital dash is by the passenger valve cover area. It is attached to a bolt with other grounds as well.

i used to have problems with overheating and the fan not turning on cause of a bad ground wire there. (GM made the wire very short and when i had bad motor mounts it somehow pulled on the wire). I relocated the gruond for the fan to the rear of the firewall.

Sometimes when i hit a bump, my dash goes crasy with all types of symbols and letters cycling through. It is probably also caused by a bad ground. I am eventually gonna have all the grounds relocated to a safer place and hopefully that will solve the problem.

What should i do? Replace the VSS or take out reducer?