Eratic Speedometer
 

I have an 88 Special Service Car with the 140 mph "certified calibration" speedo. Well I dont think it will pass certification anymore since it moves around like a damn polygraph needle and goes all over the place. I'm hoping its just the cable. Or does this sound like an internal problem with the speedo.

Do I have to have a specific cable for it, or can I use any 140 mph cable from a regular 140 mph speedo.

Also my fuel gauge always reads empty.... You guys have any ideas of what may be wrong or how to troubleshoot the problem?

Thanks all!

Always remeber that the factory gauges are junk. Sounds like you need a new speedo cable and a new fuel gauge. I am in the process of changing from an 85 speedo to a 140. I am going to use my 85mph cable. I have been told here on this site that it can be done. I can't see where it won't work. Just as long as you have the right trans and speedo gears, it will be pretty accurate.

Pull the cable outta the trans. Its a 7/16" bolt, and just jiggle to get it out. The speedo gear on the end of the cable should be "square" like a soupcan, not like an hourglass.
Thats an easy check/$15gear fix.

Ya, my bet would be on the speedo gear particularly if you or the previous owner changed the rear end gears (some of the different speedo gears are notorious for breaking apart).

No one had said anything about the speedo its self!!! You dont think it could be that? I am just asking cause I have the "SAME DAAMMM PROBLEM" Looks like it wants to spin around acouple of times.

What do ya think??:confused:

You'll have no problem with that.

Mine's erratic as well, I haven't checked the gear.

9 outta ten times the speedometer itself is perfectly fine and its the speedo gear or the cable thats the problem. Just check the gear first and then maybe spray some good ol wd-40 on your cable to make sure its not sticking anywhere. As for the fuel gauge, get an aftermarket one.

Well here is my update on the crappy speedo problem. Try'd to lube the cable..NO LUCK same problem..I guess I will try to replace it.

I'll keep ya posted.

The speedo probably has a bad cable.
The fuel gauge is probably a bad sending unit. Thats in the tank of course, and if you have my luck the tank is full:rolleyes:

Well theres no reason you can't drive it until you run out and then change the sending unit... I would just advise staying within a few miles of home until you do run out.