I have a 91z28 and I just put a new Auto Meter electrical speedo gauge in it. I also have a T56 trans so I am having issues with the VSS working correctly. my question is which brown wire behind the dash goes to the ECM for the VSS signal? I looked at chevythunder.com and it shows that there is actaully 3 VSS pins in the ECM. 1 is low 2 is high and the 3rd is VSS output(brown wire). I need to know how to hook this gauge up so that my SES light wont give me a faulty VSS signal like before. I have an OUT and SIG on the back of the gauge. the plug that was plugged into my T5 trans has a yellow and purple wire on it .there is a wiring diagram that states that the yellow wire is VSS input and the purple wire is ground. it also shows both of these wires going to the ECM. it shows that there is also a brown wire at the ECM that is lableled VSS output to the gauge cluster. Now, do I just take the correct brown wire that goes from the ECM to the gauge cluster and plug it into the SIG on the new gauge? I could have swore that I would have to take the yelow wire(signal) on the VSS plug and hook that to the SIG. then ground the purple wire. then take the brown wire and hook it up to OUT. What has me stumped is which direction the speed signal takes. does it go from trans to ECM to gauge or trans to gauge to ECM?

 

Check out this diagram and see if it helps you any.

 

that does nothing for me. my car dont have a buffer box. I have a 91 with a VIN F.

 

That ain't a problem, look at it now!!!!!!!!

 

what is different? Maybe I am wrong and my car does have a VSS buffer but I could have swore it didnt. I just need a straight anwer onhow to properly hook up this speedo so that my ECM sees a signal and its the right signal. I took the cruise control out of my car if that has anything to do with. I need this hooked up right before I fire up my new engine for the first time. The last time I had the stock dash and the SGI 5 box, i could never get it right and I ended up disconnecting it and it caused the engine to idle at 1000RPMS all the time and I cant set the timing like that.

What would happen if I just plugged the yellow/purple wires into the VSS on the T56. what would that do with the ECM?

 

ahhhh. its fixed now. thank you. i think I drank too much cuz I think that pic was different a sec ago

 

ok it shows that a gray wire is the wire I need to find that goes to the gauge cluster. Now is this the wire that is feeding the speedo the corrected speed?

Im still confused about how to hook the speedo up

 

It was..........that's why I'm The Trickster!!!
I cheat!!!!!!!!!!!!!!!

 

take a peek at this wiring scematic for the 90-92 cars. it shows that pin location B 11 is brn and not grey. where there 2 diff clors used on the 90-92 cars

http://chevythunder.com/fuel%20injec...ts.htm#1990-92 speed density f-body (ecm#1227730)rs

 

Well either that link is wrong or the 92 GM service manual I'm using is wrong. Take a look at this schematic.

 

hmm, thats interesting. Wel at least the same PIN location right. I will take a look at that on my car this weekend and try to trace it back to the wires behind the cluster. It is possible to use a multimeter and trace wires right?

Now with these diagrams being up, does it look all I have to do is hook the SIG terminal on the back of the Auto MEter gauge to the correct wire from B11? remember, this speedo is programmable I just hope it is still programable hooked up like this

 

this comes off the Auto Meter site:


NOTE: This speedometer provides an output (OUT) terminal that can
be used with late model vehicle installations using the existing Vehicle
Speed Sensor (VSS). In these installlations, the VSS signal wire should
be connected to the SIG terminal of the speedometer only. The OUT
terminal should then be connected to where the VSS output was
originally wired. This will provide a buffered VSS signal to the
PCM/computer in the vehicle.

Now with that beig said, how you someone go about hooking this up per those above diagrams. I am lost here. Auto meter says "the VSS signal wire" should go to SIG. Isnt the yellow AND purple the signal wire(s)? Am I gonna be doing some splicing here to hook this up

 

Do you have a link to their web site?

 

here is the link to the page that lets you click on the desired gauge. I have the 510.pdf gauge.


http://hp.autometer.com/instruction_...edometers.html