I need to know what vss # i need for a 92 z28 with a 5 speed and 3.08s in the rear. if you have this same setup please help me. i need it. it could be D8I, D8A, D8B, D8N, D8M

 

The VSS part # is 10456087, electronic speedo for T-5 with 3.08 gear. Not sure what rpo code it is but that part number is the one you need.

 

YOU SURE THAT IS FOR TPI?? OR IS THAT FOR THE RS????

 

When I changed from an auto to T-5 , the t-5 came from a 92TPI GTA Firebird with a 3.08 rear. My car is an RS. After researching, pulling out hair screaming and kicking trying to find the part number for "TBI cars"(Because most parts houses including GM go by the RPO code which diddnt help me because my rpo said auto trans)it turns out that this part number that was in the trans to begin with was ok and will work with TPI or TBI w/T-5.The confusing part is the RPO codes because some different rpo codes will use the same VSS , just different Spedo gear(which diddnt come with my VSS anyway) The only difference with the TPI cars and the TBI cars as far as the vss wiring is concerned with your year car is the purple/yellow wires on tbi cars goes to the speed buffer then to ecm,speedo,cruise,etc. On TPI cars the Vss pl/yel wires go to the ecm first (Speed buffer is built into the ecm on 7730,speed densityTPI)then the ecm will send it to the speedo, cruise etc... So yes I believe that is the part number you need.Hope this helps , sorry to be winded but I really had a tuff time finding out what your looking for and dont want to see you go through what I went through.

 

WOW thanks i noticed that, when i did a search for vss and your name came up like 10 times. I thought that the difference was that one is two pulse and the other is four pulse. I have a speed sensor in there already and it is for 3.08 but it is the one i had on ther when I had tbi on there and it doesnt work at all. this is what is confusing me.

 

TBI=VSS signal to VSS buffer out of buffer to ECM,Cruise,and ABS if equiped.

TPI=VSS signal to ECM (7730) out of ECM to speedo., Cruise,and ABS if equipped.

What you need to do is find the wire from the ECM that sends the signal to your speedo and connect it to the wire that came from the VSS buffer for the speedo.

 

WHERE DO I FIND THAT AT? sHOULD I JUST FALLOW THE VSS WIRES BACK TO THE ECM? WHERE IS THE BUFFER LOCATED AT?

 

I think I have read that they are a little yellow box behind the passenger side kick panel.
You can actually eliminate it and connect its out-put wires to the ECM just get a factory manual and follow the diagrams.
Someone on here knows for sure on the location of it though.

 

The Vss Buffer is just to the left of the ecm under the dash, its a small square type thin electrical component you cant miss it. There are 2 screws that hold it in that are on the bottom of the dash right were you took the screws out to lower your under the dash kick panel to access your ecm. There will be 2 connectors going to it, one will be the VSS harness yel/purple and the other connector will have a 5 or 6wire harness. The pin out on the VSS buffer are: first conn. A and B yel/purple = VSS. second connector: A=ground Black, C=speedo green , D (not sure mine isnt used could be for additional accessory) E= Cruise control (if equipped) Red, F = goes to ecm Brown, H= ignition feed mine is pink/black stripe. Being that you switch to tpi, your vss wires go to the ecm now. your speedo wire will go to the ecm output now(4000 pulse output). If you have cruise it will go to the 2000 pulse out put on the ecm.That it . If you wired it right and your vss is ok everything shoud work. I have the pinouts for the 7730 ecm if you need more info. Hope this help you a little

 

Just to add a little note, The vss generates an AC signal from what I understand.Its the speed buffers job to make the signal useable for the speedometer and cruise control.The whole pulse thing is what the speedo reads and what cruise control reads.Speedo needs 4000 pulse per mile to function and cruise control reads 2000 pulse per mile (all of which the speed buffer sends out from info it gets from your speed sensor) When you wire it up to your tpi set up you will actually be eliminating your original Buffer and useing the buffer that is built into the 7730 ecm.

 

Ok im not quite sure whats going on but here is how I interprit it. Since I have swapped in the tpi now the vss wires the purple and yellow now go straight into the ecm so the computer knows how fast I am going. but the speedo isnt hooked up cause the wire is still hooked into the tbi buffer. So I need to take the wire that goes to the speedo from the buffer and hook it straight up to the ecm output for the vss and take the other one and hook it up to the cruise control. then i will rip out the buffer **** on it and burn it cause of all the personal anguish.
is this right??

ohh yea i have the tpi wiring schematic too so dont worry bout it.

 

That sounds about right but, I don't think I would burn it.
Hell you could probably sell it.

What I think is going on, even though it really don't matter is that the VSS buffer has no signal so therefor can not send a signal to your speedo or cruise.

You should have a connector in the TPI harnness that has the out-put wires for the speedo and cruise so just take them and connect them to the correct out-put wires from the buffer and you should be good to go.

 

do you know where those wires are or what color they are??
I know the ones for the tpi but not the tbi buffer wires.

 

Yes , you are going to eliminate your old speed buffer because the tpi ecm has the buffer built into it. Your on the right track.Once your vss is wired into the vss high and low inputs on the ecm, the ecm will know your speed. Now take the speedo wire which should be green/ terminal "C" on your old buffer (colors may vary)and wire that to your 4000 pulse per mile output on your TPI ecm.If you have Cruise control take the red wire terminal "E" and wire that to your 2000 pulse per mile output on the TPI ecm.If you dont have cruise control disreguard the last instruction for the red wire. Now unplug your old Speed buffer and your done. Thats it.Were you able to find your old speed buffer?When you find the speed buffer you will see the terminals are all marked with letters.Do you have the pinouts for the 7730 ecm so you know where to put your wires?Im going to look it up and I will give you the pinouts you need.I gave you all the colors and terminal identification in my previous post for the buffer.

 

7730 ecm = speedo(green) wire needs to goto pin- BB 11 on the ecm . If you have cruise (red) it goes to pin- BC 1 on the ecm. VSS purple goes to vss low pin- BB-9 Yellow goes to VSS high pin- BB 10. Let us know how you make out.

 

I have the issue solved. Last night i started taking things apart unfortuanatly had a little trouble finding the buffer and accidentally took out some ac control box but i realized pretty quick that it wasnt it cause none of the wires matched up. But I cut the green wire off the buffer due to the fact that it goes to the speedo and I took the speedo signal wire off of the bulk connector right by the ecm and hooked it up. IT WORKS not exactally right but it did work unfortunatly it was only calculating half of my speed. to fix this i realized that the cruise control still works off of the 2000ppm signal so i just hooked it up to that seeing how i never use cruise control. Now everything works perfect. NO worries. Later i might get the right speed sensor but probably not seeing how it works just great. just one more question though. if I hook up both the speedo and the cruise control to the 2000ppm vss output will i hurt anything or will this be alright. I will need to hook up the c.c. befor i sell it so Im just wondering. Thanks for all your help guys. couldnt have done it without you.

 

Im telling you , you have the correct speed sensor..... You have your speedometer wire going to the 2000 pulse per mile out put. that output is for the cruise, leave the cruise wire there.... that is why your speedo is not reading correctly. Pin B-11 (on the 24 pin black ecm connector) This is the speedo output .Put the speedo wire there and solve your problem. Dont wire the cruise with the speedo on the same pin , you may overload something and its just wrong, do it right and you will be much happier.

By the way my old speed buffer is white , not yellow I think the older cars had yellow ones.

 

I tried hooking it up right and it only read half of my speed and that is why I have it hooked up this way.