Chad Were Wolfe

I have a 91 camaro rs with a v6 and the speedometer isn't working. Occasionally it will jump around like it's trying to work but most of the time it's just dead.

Let's go over what I've done so far to try and fix this. So my first instinct told me it was probably the vss but I took it to the garage next door so the mechanic could hook it up to his diagnostic tool and tell me if the signal was getting to the cluster. He tells me that the ecm is getting the signal from the vss and that someone tried to install a security system and the wiring under the dash is a mess and that that's the problem and I would need a new wiring harness.

I was fortunate enough to find an untouched dash in the same year and model camaro in the junk yard so I nabbed that one and swapped it with mine since I was told it would be easier to do that rather than switch just the wiring. I left the original cluster in to keep the mileage the same. Once I got the old one out I realized the wiring wasn't that bad but there was somethings spliced in and some of the wiring under the driver's seat was chewed on by mice I assume. Well, that didn't fix it but at least I have piece of mind that all the wiring is good in the car.

So today I put the other cluster in hopes that it would work but alas it does not.

What do you guys think? The speedo does work very sporadically, is it possible that it just happened to be working when the mechanic tested it? Could it be the wiring from the vss to the ecm? How should I go about testing to see if the vss works?

Sorry for all the questions but I just really want to get this thing fixed. Any suggestions or advice is greatly appreciated. Thanks in advance!

Berlyn0963

iTrader: (4)

check the capacitor on the small board inside the guage cluster. if that isnt it then try checking resistors. also try to get a known good working cluster from another camaro to swap into it. your vss should be tested for a good signal but i dont know how , i just used a new one since they werent terribly expensive. dakota digital sgi-5 is something worth looking up if ur ECM is crappin out, it replaces it with converted signal from vss to the speedo cluster (this is for 89-92)

1983Chimaera

If your system uses the yellow VSS buffer box, you can send this output directly to the back of the speedo on the cluster. Look up the tech article on thirdgen.org for installing an electronic speedo, this is what I used on my 83 Z28. This will let you rule out the ECM as the problem and diagnose the speedo head at the same time.

The buffer box takes the 4000 ppmsine wave output of the speedo sensor and clips the signal into a digital 2000 ppm input to the speedo. They can be found in junkyards in the 86 up Firebirds fairly easily.

Chad Were Wolfe

There are two small boards in my cluster. I'm thinking the one on the left is the one for the speedo?

Yes, mine uses the yellow VSS buffer box which was replaced with the new dash I put in. I doubt that I'm unlucky enough to have found two bad ones. I'll try and find that thread but if you could provide me with a link to it, I'd be very grateful.

Thanks for the responses!

Chad Were Wolfe

This is what the one board in the my original cluster looks like. It's ugly and I'm thinking it's the problem. I suppose the cluster that I pulled from the junk yard (which is currently in the car) must look similar to this one. Anybody have any schematics for this board?





Ignore my cat in the background. She likes to help me work on things sometimes.

1983Chimaera

http://www.angelfire.com/mt/psh/speedo.htm

There ya go. Worked great when I installed my electronic unit. If you go directly to the back of your speedo there should be 3 screws that you can run the signal to. The article tells you which wire goes to which terminal. This will bypass the computer and the rest of the circuit cluster entirely, giving you a direct link between just the VSS sensor, buffer box, and speedo itself. I'm running a 1995 Camaro Z28 speedo this way now, and it has been verified as accurate. I've also run 3rd gen speedos the same way.

mrhorton28

Im having a problem with my speedo and odometer...both have stopped working. all other gauges work. just replaced the speeo cable...worked for about an hour of driving then just stopped again. I NEED HELP!!!!