hey, here is the deal, i have a trans am, vin and reg says 86 ,but vin also says cengine code h and from what i read it means
H = 305 ci V8 LG4 MFI w/AT (1985-1986)

but my car is manual t5 trans ,and the hump for shifter is factory so doesnt make any sense as far as when they say its at , but for motor,what was in there when i bought it was a 350 carbed,not stock,but there was a computer,with everything unhooked behind the dash,everything exept the orange wire that feeds the ecm,the grounds,and the four wires comming from the trany,2 for back up lights,and a purple and yellow for speedsender cause my car doesnt have a speedo cable,so i cut every other wires but left those in,my speedo was still working in the car,,,now 7 years after i took it all appart, im ready to drop a tpi from a 87 iroc,and i wanna keep my trany,so i want to still be able to run my speedo like it used too,but here is the problem, i traced the purple and yellow wires from the trany into the car,then i plugged it back in the connector at passenger underdash,but that connector is going to another connector,then nothing! i cant find my old computer but, i cant sse a 2 pin plug being on the ecm,is there supposed to be a yellow buffer box there? and if so,from it,where would the signal go?i have the whole dash facedown on a couch,and i cant figure out how to bring signal from trany to speedo,does it have to go in a buffer box,then to speedo? or from buffer box,to be processed by the old ecm then speedo? or directly in old ecm to speedo?sucks that i lost the ecm cause i have no clue wich one it was,i know it wasnt tpi,could be 305 tb or electronic carb or v6 mpfi,,,i just dont know.please someone explain to me how to get my speedo back with those 2 wires! the tpi ecm im puttting now is from auto trans car,needs vss signal for tcc,but i go manual so i would assume there is no other reason why it would need that signal right,like i said,it was working before but i dont remember how it was set up,there is no empty connectors at the cluster,but maybe it comes in by the pluggin that goes from the ecm to the aldl and guages and fuse and whatever goes to driver side. if i could id just like to make it still work like it was independently fron the tpi harness,even if i have to hook up the old computer just to run that,id have to find out wich computer it was though,the whole bracket is gone so if there was a vss buffer close to it,its gone as well.please help

 

the signal goes from the trans vss 2ppm to the yellow box (4 out speed buffer) from the speed buffer to the ecm stock ecm took a 2ppm signal. the light green and red went to the speedometer and and pin f went to the ecm. If you are going to tpi maf vss in put to pin a10 of the 1227165, if you are going to sd use pin b10 1227730

 

more info on the subject here

http://chevythunder.com/speed%20dens...n%20manual.htm

 

ok so if i understand well,the connector i have now has 3 pins but only 2 are used, purple,and yellow,that plug would hook up in a yellow box,right?
,and from that box,wich i still have to find cause i took it out i guess,there is none,there issupposed to be a green and red wire going to the speedo? do i tap these in the plug that connects outside harness to ecm and goes to guages? ill check if there are green and red going to clusters there cause there is no other wires other thant that main harness, ok,and then the ''f'' pin going to ecm is the f pin on the yellow box?
,and it would go on pin a10 of my 165? so i dont need the old ecm anymore right? you might get frustrated trying to get me to understamd but this is all first time for me that deep behind a dash!! one thing i would have to know is the pinout on my cluster,would tell me exactly where those red and green wires are,and i could follow them to see where to tap into them,please dont let me down,im getting there!lol , ill also go look in one of my parts car for another one of those yellow boxes. by the way,what could be the lil blue box behind the dash at the same spot?

there is a light blue greenish box,with bunch of wires going to one side of it,and there is a lil door that opens at the other end so you can see resistors or whatever they are in there,just curious

 

oh! thanks buddy, i took so long to re reply that i havent seen the link!!! good stuff, im printing it and i goin hide in the shop for the night!!!! thanks 1000 times

 

see the link, if that's not like yours maybe you need to get a schmatic. If you had a car had a tbi ecm you cannot use it for tpi.

 

yes well the link is for map(sd), i have maf , i have the whole harness and the 165 ecm off the donor car, but my car was another motor,probly tbi i dont know,all i know is there was a computer,but i dont have it anymore to tell wich one it was,althoug the 2 connectors are still there,maybe i could identify by the number of pins

 

i have all kinds of schematics for the tpi maf im installing,but it was limited to the tpi harness,i didnt have any info on speed buffer vss whatever exept the pinout that said,one wire was comming from or to it.didnt know until a bit of research here that i needed a yellow box.

 

https://www.thirdgen.org/forums/tran...-location.html

 

so is the vss buffer box only used for an electronic speedo? i'm working on swapping to an lt1 and i read about bypassing that, but i have a manual transmission and an mechanical speedo. this may be dumb questions, but i didnt know anything of the vss buffer until i started my swap and read about bypassing it