Trying to figure out wiring for 88 Iroc with TPI. Haven't pulled cluster yet but since it has stock transmission and cable have question about VSS signal and VSS.


From research the speed signal goes through the yellow
buffer on the back of the cluster and outputs 2000 pulse per mile. That signal then goes to the cruise and ECM.

My question is what does the ECM do with the VSS signal?

 

Tcc lockup, iac control, fueling based off load /speed, speed cut off. Why ?

 

Was hoping if I could ignore it Doing a Dakota install so looks like I need to tap back to the ECU the speed signal since it actually matters.

I am looking through the wiring book as to which pin it is on the ECM as looks like a brown wire.

 

If you have an automatic transmission, the ECM uses road speed as one of the deciding factors of deciding when to lock / unlock the torque converter clutch.

 

And again, TP beat me to the post by mere minutes, lookin like Imma gonna hafta be quicker on the draw here.....

 

Oh that was what I was trying to figure out if it mattered and appears it does. I will wire it up so the speed output from the Dakota box gets fed back to the ECM connection.

 

Now I need to figure out how to get at the ECM lol. These projects never can be simple.

 

Here ya go, for controlling a lockup converter without an ECM, this is one company that offers a solution;

https://www.tciauto.com/tci-universa...-gm-700r4.html

OOps, just noticed the one I linked is out of stock, but if ya search around I'll bet you'll find one for sale somewhere, like Amazon, who claims to have 3 kits in stock;

 

What was the first year they started using magnetic/electronic speed signal instead of the cable? Don't want to get a surprise when I get under the car and find now cable lol.

 

I'm sorry, I know the last year for speedo cables in the 'Birds was 87, cause my 87 TA was cable, and my 88 parts car had the VSS on the transmission like my 89 does, but I don't know the answer for the Camaro.

 

Your '88 will have a speedometer cable between the trans and cluster. The optical pickup on the back of the cluster creates the VSS pulse stream.

The Camaro's went to the 4-PPM magnetic trans mounted VSS in '90.

RBob.

 

Thanks, hopefully no suprises as a dig into this.