My speedo quit working in my 91 RS 305 TBI. Where do I start to find the problem. I crawled under the car today and the wires to the trans are all connected. Would it be the tranny part or the dash gauge itself? Thanks for any help you can offer. I just got this car about a month ago. i know nothing about working on it.

 

Any noises as if the wire in the back is loose? My speedo cable was working but it was making a racket; seems my speedo was broken. Switched it with a 145 speedometer and replacement cluster. Not sure if my speed is accurate but it seems to work!

Get a chilton book but if you end up having to, there are 2 bolts underneath the steering column that hold it up, first remove your plastic pieces around that area, this should let you drop the column to work with the area easier. You'll need a torx screwdriver (forgot the size) to take the faceplate off, you'll then need a metric 10 long ...
Found a link that I went off of to fix my headlight switch, same thing on removing the cluster which holds the speedo.
https://www.thirdgen.org/forums/elec...switch+removal

Like one of the guys there, my book said that I could possible remove the speedo from the top but it was blocked off, I had to remove the faceplate, unbolt the two 10mm bolts that hold the gauge cluster, that left the cluster held by the speedo cable. I had to wiggle my hand in there and push down on the clip while tugging a bit and it came out. Scratched up knuckles!

I've actually had to move things there quite a bit since, my speedo went out -fixed it. Then my headlight switch went out =fixed it and had to refix it several times when I kept finding small electrical gremlins.

 

does your cruise control work?
If not it may be the speed sensor.
If you don't have a cruise control it still may be the speed sensor. do you get any codes??

 

I haven't tried the cruise control in a while. No check engine light at all. My tranny just lost 3rd and 4th gear. It is up on jack stands in the back yard now awaiting a new tranny so I can test out the cruise control. Would the fact that my tranny went out cause the speedo to quit working? 1st and 2nd gears still work fine and the speedo doesn't work at all. Thanks.

 

You could have a problem with the drive or driven gear for the speedometer in the transmission, but that should cause the check engine light to come on. You won't get the check engine light for a vehicle speed sensor problem until after the car is moving for a minute or so.

My speedometer didn't work when I got my car because the driven gear (what the speedo cable hooks to on the transmission) was chewed up and was not connecting to the drive gear. It quit another time on the freeway after a nice clunk noise because the speedometer cable came loose (my fault ) and sheared off the end of the cable. I got the check engine light for that time, but I don't think it was on the first time around.

You have an electronic speedo (any camaro after 89) so you couldn't have a speedometer cable problem but you do still have the drive and driven gears in the transmission. I would start by checking on the driven gear to make sure its teeth are in good shape, its located on the transmission tail where your speedometer wires are hooked up.

 

I'm not sure the check engine light comes on at all for the VSS. My VSS is out so is my MATS. Check engine light comes on only if I get on the gas real hard or drive it for 15 to 20 miles, I almost never go that far I have two entire towns that fall 100% within 10 miles of me, so a twenty mile trip one way is a real road trip lol. Anyway I think that in my case the check engine is from the MATS but when I checked the codes to see what it was I found the VSS fault code and that splained to me why the speedo wasn't working. The cruise also for that matter.

 

my speedo dropped on me yesterday, one of the clips was loose and the cable was laying on the edge of one of my headers for a few seconds too long. heh, it was burned and cause the speedo wire to lock up. so I disconnected the old speedo cable and installed the new one...still nothing.
took out the threaded gear insert for the speedo cable on my tranny and the speedo gear, expecting it to be shaved, but it's in perfect condition, so I am at a loss. I'm not sure what the gear looks like inside the tranny that drives the speedo gear. and I'd hate to have to drop the tranny just to check.

any suggestions?

 

Status update!!!

I got my new tranny installed and now have all 4 gears. Still no speedo. Got it up on the freeway and the check engine light came on after about 3-4 miles. The code was for the VSS. I installed a new VSS from Auto Zone ($50) and now the cruise control works but still no speedo. So I bought a used gauge cluster from ebay ($40) and installed it. The speedo works great now. Finally I can see how fast I am going. Now everything works. One side note on the VSS. There are 3-4 different ones. You have to check your RPO code sticker to see which one your car came with. On Auto Zone's website they list the 3 digit codes when you look up the VSS for your car. My car is a 1991 but I had to look up a 1990 camaro to find the one I needed. Good luck with your cars guys. God Bless.