hey guys i switched to carb and i have no computer now and i need to know if my speedometer is gonna work or not. i have an 89 firebird formula with a 305 tbi and a 5-speed transmission

 

On the '86 Firebird I pulled a full gauges dash from, the yellow VSS buffer was piggybacked onto the ECM bracket. (In '86, full gauges got an electric speedo, but the idiot light dash got a mechanical speedo.) Wires split from the VSS to the cruise, computer, and speedo- so it looks like the VSS can run without an ECM.

Did you try driving? My guess is the VSS will feed it's signal just as normal, but the computer won't be listening (or connected). Did you have the yellow VSS buffer in the same spot as I found it (on the ECM bracket)? Did you remove the ECM completely?

 

well i got rid of the computer today and spend all day sorting otu wires and the only wires goin ot the comp that i needed was one on the fuel pump relay, one on the a/c compressor, and one one the powersteering pump. there is a yellow box under my dash near the comp. but there were no wires goin from it the the comp so i guess i'm ok. well with the compressor and power steering pump do u know if they will still work? i guess the pump will cause it doesn;t need electronics but with the a/c compressor i am not sure. well thanks

 

ok well heres an update, my speedometer and odometer do not work at all. now wut can i do to fix this cause i just go tm y licnese and i need my speedometer so i don
't gegt pulled over

 

NO! I have the same car with a 305 TBI. The speedo never worked. I have been search for a answer for 8 months. In your case your screwed. That computer is what controlls your speedo . It goes from the VSS on the tail of the trans to a Buffer (yellow box connect to the ecm) to the speedo. With out the computer in the middle your screwed so. Do what I'm doing get a mechanical gauge, speedo cable, speedo gear and there is one more gear that you have to put in the tail end of your trans. Its a different kind then the one you have now. Just Gears it its. The electric one is magnetic(it reads the magnetic pulses as it spins, more pulse the further the speedo goes up). Go to www.autometer.com and get some nice gauges. For about 100.00 you can have one that works and looks better. That might not include the other stuff you need. I think thats just the speedo. Well there is my story about a pos speedo that I have.

>hack at it!

 

Just keep with the flow of traffic. You will learn to use the tach to tell how fast your going. Its easy once you have been staring at it for long enough.

 

well i figured out wut i had to do and it was easy. i just took one of the wires from the yellow box and ran it into my fuse panel on something that only had power when my key is on and now the speedometer and the odometer works great. if u need to know wut wire it is let me know and i will look it up cause i don't reemember rigthj now

 

Bringing this one back from the dead! lol I have the same problem I swapped from TPI to carb and also put a TKO 600 in now. My speedo doesnt work. I removed the ECM so im not sure if the Buffer Box needs some type of hook up to work or not. The buffer box is still in the car. I know it was mentioned in the last post that a wire might just need a 12v power but im not sure if thats my problem or not. Anyone have same problem or know how to fix it???? Thanks a lot guys!

 

What color wire?

 

yea bump. If anyone knows how to get speedo working after you take out ECM it would be greatly appreciated. Thanks for the help!