Need some help here from any of you knowledgable SS/SC folks that have monitored (or can decipher) the PCM's datastream....or if you have a set of ~'07 Helms Service Manuals that list out the circuitry & normal data values...

Basically in a very brief nutshell, I am grafting the OEM SS/SC boost gauge into a custom non-Cobalt application (supercharged Trailblazer SS). I've chosen this gauge because the bezel and front face / colors match the rest of my gauge cluster, and I've already been unsuccessful in having Autometer make me a one-off mechanical gauge using the SS/SC's face/needle. To me, factory appearance is very, very important, and aftermarket gauges stick out like sore thumbs. Hence the reason why I "just haven't used a mechanical aftermarket".

Nevertheless, here's my questions that I hope someone can provide me with some help. The SS/SC OEM gauge (shown below in the two images) has four pinouts. Pink, Gray, and Black/White are easy to connect for my application. However, the "boost gage signal" (Tan, circuit 891) remains a bit of a mystery. Basically, I'd like to know what datastream is being fed to the gauge via Circuit 891 from the PCM? Is it a PWM signal? 0-5v linear? Other? My initial guess is that it has to be taking the data from the MAP sensor, and my hope is that this data is strictly passed-through the PCM without manipulation (of which it'd make it really easy to graft onto my vehicle....but since nothing is ever 'easy', I'm not putting much faith into that logic).

My plan is that once I know what data is being fed to the gauge in a factory SS/SC situation, that I can pull this same data from my PCM or ALDL (or hack the PCM to generate a new output via a new pinout...with the help of a local renowned tuner) and feed it to this gauge.

Those of you that use HPTuners / etc should be able to see what is being fed to the gauge. Just as good, if you have a set of Helms Service Manuals those will certainly show the Circuit 891 schematics, as well as the values (data-range) being fed on that circuit - if anyone could look this up for me and/or scan those appropriate pages, it would be IMMENSELY useful & appreciated.

Thanks for the help guys.... Getting this gauge to work in my application will be the icing on the cake!

 

on our cars it is connector 1 the bottom gray plug on the pcm and is pin number ten. im installing this in my redline and have all the wiring diagrams thats why i know that lol im not that good, i will say this tho do not go off the write up on redline forums it is not correct. let me know if that helps

 

redline87 - what's the name of pin-10?

 

boost signal, on the diagram its boost signal connector 1 the bottom one pin 10 that is where the wire runs to

 

Thanks for the info; unfortunately it doesn't help me too much. I was hoping the designation of the pinout was labeled as something different, but unfortunately not. The location & connector aren't the same between the Cobalt and the LS2 in the TB-SS.

Others?

 

And why exactly didnt you call me on this? LOL Call me dork!

 

LOL, who do you think is my local tuner?

You've got enough on your plate, I didn't need to bother you with also trying to figure out the required datastream as well!

I'll dial your # tomorra'.

 

Call me I tried to call you tonight LOL TTYL!