Well, I've been having some issues with my speedometer since I first bought my car. Nothing too serious, but tonight was the final straw. Now I want to get this stupid thing fixed.

To start things off for any relevance, shortly after I got the car the ECM threw a VSS code at me but it hasn't given it again in weeks since I cleared the codes.

Here is the problem. When I first bought the car, I could tell something was out of whack with the speedometer. until I hit about 15 MPH, it would always read 0. I always got the feeling that it was 3 - 5 MPH off and sometimes the needle liked to drift and do the jitterbug.

Well tonight while I was sticking on the new gauge faces for my glow gauges, I broke the needle to the speedometer. So I went into the trunk and fetched the one of the battered speedometer the guy I bought the car from threw at me ( The car originally had a 90 MPH I believe
and it was swapped with a 145). I popped this new needle on and decided to take the car for a quick drive. Oh what is this? I am driving 10 MPH down my street and my speedo actually reads 10 now. 5 MPH? No problem. Hey even 15 and 20!!! So about half an hour later I realize I needed some double sided tape to fine tune these gauge faces. but it was almost midnight so I hop onto the interstate to head to Walmart. I'd guestimate I was doing about 70 MPH, but my speedo insisted on telling me I was doing 90 - 100. It gives accurate readings up to about 30 - 35. Anything after that and it loses control. I'm almost positive that the exaggeration gets worse the faster I go. Any idea what the problem is here?

 

cable driven speedo or electronic?

 

Providing the make, model, and year of your car is helpful in nearly very question you might have, for example in Camaros the speedo is mechanical from 82-89, electric from 90-92.

JamesC

 

Can't believe I forgot to emntion that. It's an 85 Z28 Camaro.

 

Several possibilities: The speedo head has gone south and requires replacement; the cable and cable housing may require cleaning and lubing; the cable itself has bid adieu. Start by removing the cable and thoroughly inspecting it. If all's well, clean and lube. If that doesn't produce positive results, I'd say the speedo head is the culprit.

JamesC