i have a 1991 RS 305 Camaro and my speedometer and odometer never work to start off my driving. After a while, sometimes it will start jumping a little bit and then start to work (not sure if it is 100% accurate when it does that though). Once that happens my odometer begins to spin correctly as well. By looking in my Haynes repair manual it looks as though i have a cable driven speedometer, although through searching on the forum most post seem to point toward electric. I have no idea where to begin because there are no pictures or anything for me to go by. Any ideas if this is a worn cable or what? Thank you.

 

Your 91's speedo is electronic. The vehicle speed sensor or it's wired connection may be faulty. I'd suggest you first make sure that the wired connection is good. It's located on the drivers side of the transmission tail housing and has a yellow and purple wire connected to the vss. Start there.

I had this same problem with my 91RS. Once with an open wire at the connection. Once with a bad connection at the back of the cluster inside the vehicle.

If your vss is going bad, go to the GM dealer for your replacment. Take your vin number with you, you'll need it for the correct part as there are a couple to choose from.

Good luck

 

so if all the connections are ok, it would most likely be the speed sensor?

 

You might want to check the connections closer than just visually. Do you have a test set that you can verify continuity with? If so, you can check the wiring from the vss to the computer, one will show full loop and the other with resistance. While the connector is apart and your testing these wires, move the connector and wires around, see if it goes open at any time. I found a problem (intermittent short) at the vss connector that way. Also, closely check any exposed wiring near the vss that may come into contact with the transmission. I've found shiners (or shorts to ground, where the wiring insulation was gone and the copper conductor rubbed against the housing).
While under there testing, put the test leads across the ends of the vss. If it shows a closed circuit, the sensor should be good. If not...well, there's your problem.

Good luck

 

I got the same issue, also on a 91 RS. My VSS is electronic, I replaced the sensor and it wouldn't work at all. Put the old one back in, and it works sometimes. Seems to work better at slower speeds. I have pulled apart the dashboard, everything is good there, all wiring from sensor to computer to dash is good. I have a new sensor and new gears, will get those replaced soon and update you on my findings. With it working good at lower speeds, then not at all at higher, I am expecting to find that the gears are slightly worn out, and slipping at higher speeds.

 

Ok, my problem is fixed. I troubleshot it down, and got the parts, ended up being cheaper than I thought.

If you really want to know exactly what the problem is, this is how you test it. Jack the rear of the car up in the air. Take the sensor out of the side of the transmission. Get a power drill and attach it to sensor shaft. While sitting next to the car and the drivers door open, you should be able to see your Speedo while you use the drill to turn the sensor shaft. If your Speedo registers MPH while doing so, and it is reading it steady, then all your wiring, computer, and Instrument cluster is fine. Your problem will be in the gears for the sensor. I recommend switching both of them out.

Next question, if you ever changed the rear end gears, and never changed the Speedo gears, now is the perfect time to do so. I got both of the gears at the dealership for a total of $14, and a brand new sensor at ORielly's for $35.

You and I had the exact same issue, as by what you had described. I had troubleshot mine down, as no one had given me any advice on what it could have been. I had it in the shop yesterday morning, replaced the gears and sensor, all is fine now. If you have any questions, email me, or reply and I will try to answer it as quick as I can.

 

I have the same problem too in my 91 RS auto trans. One question for you though. While I have my drill spinning the VSS shaft, does the ignition need to be on and the tranny in drive? Thanks.

 

Yes, you ignition will have to be on, car not running of course. Just keep your Tranny in Park. Since I replaced the sensor, the gears and the seals, all has been well. I picked up everything for about $50. It is an easy task for those that have a garage and some knowledge of what to do. I would have replaced mine myself, if I had the garage part.

 

hey my 87 did the same thing..didnt work till you drove it then wobbled then worked.now it dont work at all and i dont have electics,just a cable

 

Just wondering where you got all of the parts for $50 cause just the VSS @ Autozone is $94 here in Cali.

 

interested in thread so just leaving somthign so i can see any replys) my 87 firebird automatic speedometer is jumping like crazy. Chilten manual seeming pretty useless here. VSS looking a 100 dollars i dont have, so opening cluster up to try and look in there and try and clean or inspect cable.

 

There are several different VSS. I got the correct part number from the local Gm dealer with my VIN and then went to auto zone to get the part. I think it was around $95? Of course the one for my car had to be the most exspensive out of the five or so offered. I saved just under a 100 dollars (not including the labor they wanted to charge me), by going to autozone. It was my first time doing this and I had it done in under 15 minutes, its a fairly simple job.

 

edited this post, asked about maybe not havinbg a retaining bolt and clip on my VSS, well I found it had had taken the clip off already . spraying some wd40 around my sensor and going for ride to pick up new sensor, wish me luck. When I had looked at the instrument panel all seemed well in there. Foun d out mines also Electric. Was able to remove the plastic glass over my instrumnet panlel, as over the yrs it looked like poop and the spots didnt seem to want to clean off the glass.

 

I HAVE ISSUE WITH MY WIFE'S 92 CAMARO RS THE GAS AND TEMP WORKING JUST SPEEDOMETER RPM'S AND ODOMETER NOT WORKING NOT A MECHANIC NEED ADVICE WITH PICS PLEASE

 

Does tranny fluid comes out? I went to check my VSS but when I unplug the sensor there was tranny fluid, normal? or sign of replacement?

 

That's normal not much will come out if you are on flat ground or the car is tilted forward.

 

great info I am having some of the same problems with the speedometer jumping around I had the gears in the tail shaft replaced when I went to 373 gears. Ieverything worked fine for a year or so and now my speedo jumps all over the place thinking maybe loose connection or bad sensor.