I took down my ECM and it's an aftermarket replacement and it has a yellow buffer box right by the wiring harness. I'm wondering if its stock, and if I'll need it for my SD swap I'm doing today. Thanks.

 

That yellow buffer box is stock and it is the Vehicle Speed (VSS) Sensor buffer box.

 

If you are switching to SD, no....you won't need it.

 

I didn't see any info on removing it from the website about the conversion.

 

Are you absolutely positive that he won't need the VSS buffer box?

 

I'm having the prom burned so I use my stock VSS so basically I'm just using the pin changes listed on the tech article floating around this site.

 

Ok, I stand corrected. I believe you wiil need it.
I didn't see you were working on an '86.
If you are using a '7730 the brown wire from that buffer will go to pin #C6 on the C & D connector (it probably goes to A10 now).

 

I'm not sure which tech article that you are using, the one that I have seen on this board is for switching 1990 - 1992 camaros to speed density. I haven't seen anything for firebirds.

 

The VSS buffer is used not only for the ECM but also for the CC and speedo. The signal from the gearbox is divided in different ways in the yellow box and then used for different sources in the car

 

Hey Guys I'm hooking up a electric speedometer in my 85 Firebird (with a 88 TBI swap) and have the yellow buffer box.....I have all the wires covered except the two browns....I know one goes back to the ECM, where does the other one route to? Cruise control maybe?

Does it matter which brown goes to which....I figured the output was the same.

 

Wow, talk about resurrecting an old thread.
Look at this diagram, it will tell you which wire exactly goes where. Don't mix them up. http://www.austinthirdgen.org/mkport...SS_V8_vinE.jpg

If you need more diagrams, they are all here: http://www.austinthirdgen.org/index.php?pid=19

Hope this helps.
Lou

 

if the car is tpi, the SD tpi cars didn't have the buffer box. Instead, it was integrated into the ECM circuitry. The 90-92 TBI cars did, however, use the buffer box.

 

I have a 91 RS 5.0 TBI. My speedo is dead and the cruise didn't work also. Check engine light was on and it threw a 24 code (VSS). So I replaced with a new VSS. Speedo is still dead but no check engine light anymore and the cruise control works now. What is the problem now? Buffer box or ECM? Thanks for any help you guys can give me.

 

Big bird, I already replied in your other thread. We'll take it from there.

Lou