Speedometer off by 15 mph ( intermittent )

[cb7 calling]

I'm not going to work on my car in this weather so I might as we'll talk about it. About three days ago it was -6 degrees in the morning, probly colder. As I got to speed on the highway near my house I realized my speedometer read 50 mph. Everything else indicated I was doing 65-70mph. I was riding with traffic and my tach read about 3500. This is the first and only time I have seen this issue on my cb. Ok now the up side. I have been throwing parts at the shakes my car has for years now, nothing has worked. On that day I realized the shakes where basically gone, or at least greatly reduced. Basically the colder it is the smother the ride. I have been curious lately about the vss possibly causing the shakes because it is tied to the power steering. The thing is for the speedo to read incorrect when it's freezing sounds electronic to me, and I know the vss is mechanically tied to the transmission. Does it send a speedo signal via a wire or is it cable? This is the original vss with 350,000 miles on it so I don't remember how it works.

[sonikaccord]

It's electronic. I believe a voltage signal 0-5v.

It could be your cluster as it sounds mechanical to me. Electronics will warm up and temperature doesn't affect them as much as mechanical parts.

[illinois_erik]

read this and be empowered:
http://techauto.awardspace.com/vss.html
I refurbished my VSS 6 years ago and it works fine still
to test you shakes theory, take of the power steering belt and repeat the drive and see if you get the shakes, if you still do its probably inner tie rods or the rack is shot

[cb7 calling]

I hope its the vss, but there isn't much hope anymore. This is the second rack and third inner tie rods. I mean I have done everything regarding shakes. I'll take the belt off soon. Kinda makes since seems like the shakes got worse when I fixed my power steering leaks a little over a year ago. I should be throwing a code if its my vss though right?

[Fleetw00d]

The VSS is geared to the ring gear of the differential in the transmission. The electrical VSS generates an alternating 0 - 5- 0 volt signal that is used by the cluster to operate the speedometer and odometer. The signal is also used to operate cruise control. If cruise works properly when your speedo is losing its mind, then it probably isn't the VSS. I have had problems with corrosion on the gage cluster circuit board causing problems with my speedo and odo, fuel and temperature gages. I just found a corrosion free board in Pull-a-Part in Montgomery, AL for my wagon (the next time it is home or I'm in Galveston).

As for the shakes, the colder the temperature, the lower the pressure in your tires (smoother ride). Have you had your tire/wheels balanced? Check them for straightness or bulges in the tires? Alignment good?

[Losiracer2]

I'm having this same issue too and its not even that cold in the mornings, 55 degrees in AZ.

I tried putting dielectric grease in between the connector for the VSS but its still doing it. My Speedo is off by 10mph at 70mph (reads 80mph), I checked with a GPS to verify. That might also be skewing my fuel economy calculation too since the odometer goes off the cluster's speed reading to keep track of the trip meter, reading about 26mpg mixed 80/20 hwy/city, Auto.

My only thinking is its a mechanical problem within the cluster, related to the gauges.

I'm going to swap my MPH center gauge and see if that fixes it. You do have the ability to swap out the cluster in 3 different pods once you take it all apart, in addition to the odometer stack on the bottom which is nice in case anything breaks.

Its weird, immediately when i start my car, the speedo jumps to a 15mph offset. I drive around for about a mile and then my speedo finally jumps up to the correct speed, or so it thinks. I think my speedo reads right up until 50mph then above that it starts reading incorrectly. Its really pissing me off.

This new daily I got has had the majority of the problems in the cluster.

First the coolant temp gauge was stuck, took it all apart only to find out it wasn't broken, just stuck, so i left it and now its working again. Next, the cluster was about to turn 180k, then 50 miles later it rolled over to 280k. So, luckily I had a spare 93 from my could that happened to be 500 miles off from my DD's cluster, put that in. Then the right side light bulb blew out, had to remove it again (3rd time now). Now i'm having issues with the speedo not working in the cold. I'm tired of taking my dash all apart to fix this stupid thing.

I should've just swapped the entire cluster first time around.

Crap I just realized this was from Feb. 2014 not 2015....oh well.

[johnl]

Basically the colder it is the smother the ride. I have been curious lately about the vss possibly causing the shakes because it is tied to the power steering. The thing is for the speedo to read incorrect when it's freezing sounds electronic to me,

I think that thinking your vibration may be associated with the power assist in the steering system is grasping at a rather thin straw (but I've been wrong before...).

I've often found that many cars handle and steer better in cold vs hot conditions, sometimes quite a lot better. I find most of the cars I've driven are noticeably better controlled and 'stiffer' in colder temps, most noticeably when you drive one half of a commute in the daytime (warm) and then the return trip in the night (cooler), which gives a more or less back to back comparison.

Cold temperature affects at least two things that are related to this:

The stiffness of the dampers increases because the damper fluid thickens up as it gets colder, so the fluid is harder to pump through the orifices, and less will leak past the piston seals. A weak damper may not control the spring adequately when warm, but may when cold. I've noticed cars with marginal dampers that were 'floaty' in the daytime were not 'floaty' at night, and even cars with dampers that are 'OK' are more 'OK' at night...

Rubber in the suspension bushes gets harder as they get colder, so the effect is like fitting somewhat harder bushes everywhere in the suspension. And, if there were to be a significantly softened bush somewhere in the suspension that was (when warmer) allowing an uncontrolled oscillation to occur in some suspension part, then this may decrease in colder weather.

Fleetwood suggests that the tyre pressures will be lower in cold weather, which of course is true. But offsetting this is that the rubber in the tyre casing will also be stiffer, so the tyre will behave as if it had a stiffer casing in cold conditions. I suspect the two effects cancel each other out at least to some degree. It would be worth checking though (cold vs warmer weather pressures), and adjusting if for no other reason than to rule it out as a cause of your problem...

[Losiracer2]

I ended up figuring out what it was.

Previously, I had a problem with one of the odometer reels not staying, specifically the 100,000k far left one. I swapped my 93 EX 2dr odometer reel for the 92 LX 4DR one that the car was born with since i was +/-500 miles from the true mileage.

I guess the calibration between a 2DR 93 EX Auto is different than a 4DR 92 LX Auto.

Found a guy selling one from his wrecked 92 LX 4dr auto and it works perfectly now. Swapped just the odometer section too to verify and same result.

So even 9293 clusters don't perfectly interchange between ABS and non ABS cars, you've got a to pretty much get the exact model trim your car was born with.