Hello, I have a 1991 camaro that had a 305 TBI, the 305 was switched for a ZZ3 carbed, the computer is out of the car has been. I have a 700R4 tranny. Well my speedometer and odometer were working fine when I parked the car yesterday and when I got in the car this morning neither one worked. They dont move at all just dead. Now what do I need to check first to try and figure this out. I hope I got all the information you need, Im just looking for a little direction so I know what to look for and so I can get this resolved. Thank you for your time and hope you can assist me!!

 

I have the exact same car as you, i also had this exact same problem. I'd say your best bet is to first check the VSS (vehicle speed sensor). Its located under the car on the side of the transmission, its fairly easy to get to. There should be a gear attached to it, most likely red, take the gear off and see if the shaft of the vss seems loose, if its easy to shake around (mine was) then you need a new one. Its also possible the electrical part of the vss stopped working, so even if the shaft of it isnt flimsy, that could still be the problem. If its not that id guess something in the cluster. If you do invest in a new vss make sure to get the part number for the original, I know first hand that there was like 5 different models for the 91 RS. Good luck.

 

ok before i get under there i just wanna make something sure... the gear should just come off and there should be a shaft ? sorry man never messed with that area of car but see if the shaft is loose and more then likely it is the vss... electricl failure... ??

 

From what i can recall, you unplug the wires connecting the vss (very simple obviously) and then take off the bolt holding it in (10 mm...i think). You might need a flat head screwdriver to pry it out a bit after you remove the bolt. After that be careful because when you take it out, some transmission fluid may come with it, not much at all, but have a small oil pan ready or a rag or something. After that, take off the gear, yes it just pulls right off very easily. Then you can test it to see if thats the problem.

Oh, you can do something i did just to be 100% sure. This might be a little hard to describe, but hopefully i can make it so you understand. Take a drill and fit it around the shaft of the vss after you take it out. Plug the wires to the vss back in. Then have the friend turn the electricity in the car on, make sure not to turn it on all the way. When the car has electricity, start spinning the drill, this will obviously spin the shaft of the vss as well. If your friend sees the needle on the speedometer working, then you know thats the problem, if the needle doesnt move, you may have a loose connection somewhere.

 

Hey man thank you. You explained that stuff perfectly. I wont get a chance to do it till this weekend or early next week, but thanx for the help. Ill let you know how it goes.

 

Not a problem, hope you get it fixed. I know how bad it is not having a speedometer, i got pulled over the very first day i got my license just because of that.

 

Ya i know how that goes i got an owi awhile ago and i have a month and a half till i get my full license so i can not get a single ticket otherwise i lose my licesnse for 6 months again so i can not stand driving without knowing how fast i am going.

Hey do you remember about how much the vss cost ?? Just so I have an idea of the cost. Thx.

 

The first one i got was about 60 dollars, but that turned out to be the wrong model, the one i got after that was 45 dollars.

 

hey man i need some new ideas... I put in the new vss today and it didnt fix the problem still no speedometer or odometer !!! Man nothin can ever be fixed on the first try... damnit that **** pisses me off... need some new ideas whats next to fix ??

 

come on admins and moderators someone please give me some help... im a college kid and i dont wanna spend money on taking it to the shop but i cant go without my speedometer so someone help me out plz.. thx

 

My best guess would be you either got a different kind of vss from your first one (there are 2 or 3 very similar models) or theres a problem in your cluster. Other than that i can't be sure, sorry, hope you get it fixed.

 

ya i took the part number off the one that was in and got a matching one so it must be in my cluster... what would have to be replaced or i guess ive never takin it apart ... dang it this sucks

 

There is a yellow box near your ECM, it is called a VSS buffer. This could be your problem. They are cheap in salvage yards. If you have access to a scan tool you can check VSS function. Most scan tools vave a vehicle speed function where you can see vehicle speed. Other possibilities are the gear on the output shaft in the transmission or the printed circuit on the back of the cluster.

 

If you were any closer, I'd gladly help ya track it down. But it's kinda far from Texas to Iowa.

We just had the same problem on a 1992 LS1 conversion. Turned out to be a loose ground that we missed after taking the original ECM out.

Pull your gauge cluster and check the left connector, lower rightmost pin is +12V (with ignition), upper 2nd from right pin is GND. If you don't have these two connected, your speedometer won't work.

You can also put your rear end on stands, connect a voltmeter to the upper rightmost pin and see if you get any voltage when you turn the car on, put it in gear and the tires turn. That's your VSS input wire.

Let us know what you find.
Lou

 

I've had this problem more than once... The wire connection at the vss must be fully and correctly engaged even if it snaps in and looks okay. Try recrimping the vss wire ends and test the loop from inside the car to ensure that the circuit is completed. Disconnect the two wires (yellow and purple) from inside the car and put your ohm meter across the leads. If the circuit is open, no speedo. If circuit is closed, move on to the cluster connections and test back.

 

alright thx for the new list of things to check.. im a college kid and am going back home this weekend i will see if i can get some of those things checked and figured out... thx alot... will inform you of results

 

I have a very similar problem to this one. I took out my VSS and hooked up a drill to it as suggested (awesome idea, by the way) and the speedometer worked extremely smoothly, correctly. The shaft on the VSS feels pretty flimsy though, does a flimsy shaft cause it to fail because the gears don't seat correctly causing the VSS to work intermittently? I don't wanna go spend 75 bucks on a speed sensor if its not the problrem, cause hooked up to a drill, it works perfectly.

I also checked out the gear in the tranny, and it looks good, was worried maybe the drive gear was broke. So if the drive shaft on the VSS is even a little flimsy, it needs to be replaced? (cause it is, it doesn't really even feel like anything is holding it in place) And as the guys were talking about before, how can you tell if you're getting the right sensor? there's 3 part numbers each with different option codes, like 8 or 9 different sensors, and they all look the same :P

Oh, and as a side note to any other dummies like me who have this problem.. if you have the car up on ramps, its gonna drain more than just a little tranny fluid glad i had the oil pan ready.

 

THe shaft on my VSS is very sturdy, no play at all.
This could be possibly the cause of your problem.

Let us know what you find out.
Lou

 

Although I'm not fully convinced its going to fix the problem, I at least got some information regarding which of the many sensors I needed... the RPO code D8_ denotes which kind you have.

 

I put in the new VSS today, and it works like a charm. So what they said earlier is very true, the slightest bit of play in the VSS shaft probably means its shot.

 

ya i checked my wires and believe its my guages.. working on trying to get one off ebay... last one went for 61 dollars and i missed the last bet... hopefully i get this other one..

 

yes finally... my used gauages from ebay showed up today and i put them in and everything is working thx for all the help all the ideas its all good again... thx