Speedo/Odometer Problems

[steel]

Speedometer tends to peg out at 160 mph with odometer tracking like I'm really going 160. I disconnected the VSS and it makes no difference. Once in a while I'll get a surge/spike and the speedometer will read actual speed (if I have the VSS plugged in) or 0 and I'll lose the radio for a few seconds then it goes back to 160. I'm trying to chase down any chaffing wires and everything looks good. Any ideas? I'm getting a sore back looking under the dash, am I stuck with taking the dash apart? Can this be a problem with the speedometer itself?

 

[steel]

Update... the speedometer is bouncing around a lot more now and my radio is turning off then on more frequently. On my way home from work while slowing down at a stop sign the car stalled and would not start, in fact it would not even turn over. Luckly I was on a down hill grade so after letting all the other cars go by I was able to slowly build up speed and bump start it. For the next few miles the car acted like there was never a problem, the speedo ran true without a hitch, then it came back with the same bouncing problems and what not. I'm not sure, now it sounds like a ground, the battery is only a year old but I'll check to see how the alternator is doing. Crossing my fingers to at least find a common thread to all of this. Is there a tie in with the radio and the speedo? I'm trying to figure out if they share a circuit somewhere.

 

[Tony2005]

You have wiring harness issues. Check the wiring on top of the Passenger Compartment Fuse Box (left of steering column, under the dash) and the wiring under the Power Distribution Box next to the battery.

 

[steel]

Wow, Thanks Tony, two out of the four wires coming from the positive feed of the battery were just a mass of corrosion under the PDBox. I replaced them today and I'am sad to say that it didn't make a difference. I still have a speedo that bounces and mostly stays at 160 mph with the odometer keeping pace and my radio turned off/on twice on the way to work. Anybody have any other places I should look? I'm running out of time and patience.

 

[steel]

Problem fixed

Problem fixed

Just thought I'd through out the solution for anyone else that searchs and is looking for some answers. I took out the battery again last night to look under the fuse box and started playing with most of the wires (not a particularly good thing). Anyway I decided to cut the tie that was holding the positive and negative cables from the battery together (just zipped tied to keep out of the way) when I noticed that the negative connector screwed into the engine was moving. Well, that's why god created the rachet and wouldn't you know it but it was as tight as can be sooo...... I took off this two or three inch bolt and put some washers on and tightened it back down. Put the car back together and no more speedo or odometer problems, no more radio turning off. So, the long and short of it (no pun intended), it was the main ground for the battery which runs right to the engine block. I hope this helps someone before they replace the VSS or open the instrument panel up. Good luck.