Ok heres the deal.. I have put Accel DFI 7 on my car.. all that is working fine.. I have removed the stock ECM.. so now my speedometer doesnt work.. I have done searches, and found to ground the blk/wht wire going to the stock ECM... and that should get the speedometer working.. Can anyone verify this? also i need a input for my wideband O2 data loggers driveshaft input.. so can anyone help with this?

 

If this is the '89 GTA, there should be a 4-out buffer box in the car. The VSS goes to the buffer box, then signals are sent to the speedo, cruise and ECM from there. You may have removed the buffer box or re-routed he VSS signals with the DFI install.

RBob.

 

Well the buffer box is there.. I also checked and made sure that both plugs on the box were plugged in good, and the one on the trans were plugged in.. Can i just ground the BLK/WHT wire and get it going?.. I dont have any manual that shows what those wires are..
also l need to know were to get an input for the accel data logger.. Thanks

 

Grounding the blk/wht wire may do the trick. GM uses that color for ground wires, and if it is the ground for the 4-out buffer, that will fix it.

The 4-out buffer has 4 outputs, typcially used for speedo, cruise, and ECM. Can use the now open ECM output to the data logger. May need to run a 1K resistor from that wire to a power source. Which power source I am not sure, that will depend upon the input range of the data logger. It may need to be 5 volts, or maybe can use +12 v ignition switched, I don't know.

RBob.

 

Grounding the Blk/Wht wire on the 4 out buffer DOES get the speedometer going again I haven't started the loger input yet.. but when i figure it out I will post what I find.. everyone..

 

The data logger can use either a 5 or 12 volt square wave input. There's a dipswitch on the back of the PCB to select between [square wave] and [VR-type] input, I think it's switch #5. Make sure that is set properly and you should be good to go.

 

i have the same thing going on.. i have a t56 and a cal box inline with the speed sensor. before i put the gen 6 on, it worked. now it doesn't seem to work.

anyone know the location of this 4 way buffer box and where the black/gray wire that needs grounded, is at on a 91 camaro?

thanks

 

The "4 out Buffer Box" should be located on the passenger side near where your stock ECM was.. Its probably behind the Trim panel on the front of the dash.. Mine was Yellow in color (I think they all are) and had a Sticker that said 4 out buffer on it.. I spliced into the Blk/Wht wire, and Grouned it to the same location as my DFI 7 is grouned..

Maybe somone should make something fancy for the TECH section on this one being alotta people are going to different ECMs, I know it would have saved me some time.. By the way thanks again everyone.. I've got lots of help here

 

If the '91 was TPI there isn't a 4-out buffer, the ECM did that job.

If the '91 was a TBI, then there is/was a 4-out buffer box.

RBob.

 

hmmm well its a tpi car.


any ideas what I would have to do, to get this one working? I'd like to have my cruise and Speedo back. any way to wire straight to them?

 

Best bet is to get a 4 out buffer box and wire it in. The speedo wires (twisted pair) will go to the box, then 2 of the four outputs can be used for the cruise & speedo. The box also needs IGN+ and ground.

The 4 out boxes were used in TBI & MAF 3rd gens, along with TBI caprices.

RBob.