I'm helping a friend transplant a 5.0L TBI out of a 91 Camaro and have run into a slight wiring issue.

No, not a vats issue that seems to be popping up a lot here lately:p:p, I simply replaced the ECM with a spare 88 one I had hanging around:D

I am trying to use the stock 4 output vehicle speed buffer to keep the costs down on the swap(my friend is a cheap bastard:p)

Anyways, the buffer has 7 wires coming off it 4.5 of which I've identified as follows:
- purple (to sensor at tranny)
- yellow (to sensor at tranny)
- pink/black (to +12v in run source)
- black/white (to ground)
- brown (to ecm???)
- tan (to ecm???)
- red???

The .5 wire is due to my wiring diagrams all say a brown wire is supposed to supply the VSS to the ECM. My confusion stems from the fact that I have a brown wire and a tan wire on the buffer.

Assuming my diagrams are good and the brown wire I do have on the buffer goes to the ECM, where do the tan wire and red wire go to? Are the tan wire and red wire both speedometer related?

I didn't xerox any of the non-TBI related stuff from my Hayes Camaro manual before I got rid of the 89 5.0L TBI I once had:p

Any help would be appreciated.

Anyone? Surely someone has some useless knowledge on this topic :p

I just did a tbi conversion. Never heard of a vehicle speed buffer onlY a vehicle speed sensor. It is a one wire sensor on my 89.

Charlo

Charlo,
The Camaro used an electronic speed sensor instead of a cable to drive the speedometer.

At the transmission, instead of a cable, it has a two wires(purple and yellow) that go to the vehicle speed buffer. One wire comes out of it to go to the ECM. There are two mystery wires that I'm confused about.

In most cases, I'd just buy an aftermarket VSS but the guy I'm doing some work for is trying to do things on the cheap. He doesn't want to have to pay for the VSS or the parts to convert the tranny to use a cable speedometer:(

I had to go up to the chevy dealership and get the exact diagram of the buffer for the vehicle mine was coming ou of because the haynes was wrong. Even when you get it wired right if the gear ratio and tire size is different which I am sure it is it won't shift or run right, it will run and shift but not at its peak. I am working on mine at the time trying to find a way to fool the computer into thinking I am running a 3.08 gear and 225 tires! when I am actually on 37s and 4.88's...

Originally posted by COFFEYC
I had to go up to the chevy dealership and get the exact diagram of the buffer for the vehicle mine was coming ou of because the haynes was wrong. Even when you get it wired right if the gear ratio and tire size is different which I am sure it is it won't shift or run right, it will run and shift but not at its peak. I am working on mine at the time trying to find a way to fool the computer into thinking I am running a 3.08 gear and 225 tires! when I am actually on 37s and 4.88's...

Thanks for the info... I might check the stealership tomorrow:p

FWIW, the guy I'm doing the work for will be using the stock axle and probably tires that are 225. The target vehicle is a 38 Ford pickup, I believe. It won't be 4 wheel drive. It is just something he wants for tooling around town:p