Searched and didnt find anything that helped.
My Speedometer isnt working. The car is an 89 Firebird it was a TBI 305, auto when I got it. The 305 wouldnt run, and was mechanically shot (not sure how you get a cam to have that much pitting from rust but it did), So since the car was in better shape than my 86 I put the carb'd 350 in and swapped in my manual tranny, havnt got around to putting my 3.23 rear in it (blew chunks of my posi 3.43 all over the road a while back) so I have 2.73 atm. All my gauges worked except the speedometer and the gauge lights didnt work either. First swapped in gauges from my 86 which didnt fix any of my problems... Tested for an open circuit from the speed buffer to speed sensor; from speed buffer to ecm; and speed buffer to Gauge cluster all good. tested speed sensor with a multimeter while spinning the tires it is good. changed speed buffer with the one from the 86 (speedo worked when I pulled the motor and trans, but I guess that doesnt necesarily mean its still good) Test drove it and the speedo worked for a lil bit and the service engine soon was on, which I thought should have been on the entire time since I swapped to carb. the service engine soon light went off and the speedometer quit working so I turned around to go back to the shop and it started working again so figuring on a loose connection I pulled back in and unconnected and reconnected everything and made sure it was making a good connection. Restarted the car no service engine soon light or speedo function drove the 48 miles back home and still dont have a speedo.

Now that your up to speed on my issue I need help
The pins that go to the speedo are all in the bottom connector in the dash and are the ones labeled

9- Goes through one of the fuel gauge mounting screws, service engine soon light, shift up light, voltmeter screw, and connectes to speedometer at the screw labeled IG

14- only goes to the speedometer screw S

2- Goes through 4 gauge lights and turn signals and hi beam indicator and connects to speedometer screw labeled E

I'm at a loss so any suggestions/advice that isnt get a new car, or aftermarket gauges, or mechanical speedo is appreciated

 

Check the drive gear on the output shaft is firmly attached.
If / when the gear retaining clip breaks you can get intermittent drive of the VSS if the gear slips

 

Did and its good

 

bump

 

two years later and its back again aint entirely sure what fixed it last time so... any suggestions?

 

are you getting the code 24 as well ?

 

Well thats a good question I took out the "mil" since it was always on with the carb and t-5 swap

 

Time to start doing some testing to see where your loosing your vss signal or if its the buffer or speedometer.

 

Hate that I keep reviving old threads but in case anyone else has the same problem, in my case it was a weak ground.