I don't know if any one has done this but I have installed a Holly DFI and I still need the stock pcm to run the 4L60E. I think it can be done if I supply the pcm with the needed information. I think it will only need the RPM and MPH input to be able to shift the trany and it did before going to the dfi.

My question is where does the stock pcm pick up the rpm signal? Is it from the opti ? What pin on the pcm connection do I need to supply the signal to.


Thank, Rick Abare

 

The PCM uses the data from the Opti to measure the RPM, but its not a "simple" signal.... its using the low resolution pulse pattern. Do you still have the Opti, or did you delete it? If you deleted it, you may have a problem, since the PCM shuts the fuel system down when it can't find the low res pulse pattern. Not sure if the rest of the system like the 4L60E controls continue to function. I would also think the PCM needs throttle position to control the tranny, and maybe even MAP, but I could be wrong. It is possible to wire the TPS and MAP in parallel to both computers.

 

Check with Mac at Fast track performance you will have to share some sensors... other option is a t-com tranny controller from TCI

 

I've done this before in a 95 chevy truck. The guy just ran the two computers parrellel with the major sensors (TPS, MAP, etc)

 

I did this once a long time ago. I remember right, if PCM is still getting an rpm signal (from the Opti), a VSS signal, and TPS voltage it will work. Try it and see. If it doesn't, as Fred suggested, it may need a MAP signal. To get full funtionality, it also needs ECT if I recall right.

FWIW, if for some reason I wanted to run the 4L60E with a setup that needed an aftermarket ECU (which is really an odd duck, IMHO) I would just get a manual valve body and lock up switch and be done with it. But the whole combo sort of escapes me, so you are probably thinking of it differently.

Rich

 

Not sure but you may be able to swap in a 92-93 non electronic valve body and as Rich suggested use a lockup switch of some sort...Just another option ofcourse..

 

Then you would also need to put in a hole for the T.V. cable or change cases.