Swapping from tbi to sd tpi, I was told I need a vss adapter to go from my current 2 pulse signal to a 4 pulse for the 730 ecm, first off I emailed DD and never got a response, so which one do I need? I was told it should be a "pass through" style, and how exactly would that be wired in? My motor swap is being forced up to this next weekend and I gotta have the adapter like asap along with the basics on it

Any info would be appreciated!

 

half of my question was answered by calling dakota digital, i need a sgi-5, im keeping my t5 (for now) it will be swapped for a t56 later, would it be better to just use the sgi5? Ive been told you can move a wire (brown i believe it was) not sure where, and then change the prom settings to optical output instead ( like my 89 is running currently) I have to burn myself a prom anyway, so would buying the sgi-5 be a waste or is it absolutely necessary for the t56? I might as well do something to benefit me later if it is worth it but right now i just wanna do the dang swap ive been waiting around far too long now im getting ancy!

 

Whew, what a jumbled mess

First, you dont need a converter box for the ECM change. Just bypass the buffer box and run the VSS directly to the ECM. The VSS outputs the proper signal already, then the buffer box has to "dumb it down" to a signal the ancient ECM can understand. The 730 ECM is fully capable of doing this internally so a simple two wire bypass will suffice

Next, swapping the T56 in WILL require the converter box because the signal type is totally different, not just a simple ratio like 1/2

The T5 outputs 4000 pulse per mile
The T56, depending on the year outputs 11 or 17 pulse per revolution

Totally different. Newer LTx/LSx PCMs have no problem with different signals as they have a user defined conversion factor, so you just change the number. Old ECMs like the 730 have a fixed value that cannot be changed, so you change the VSS drive/driven gears in the tailhousing to gear up/down the VSS to match what the ECM is expecting. Since you cant do that to the extent the ECM is expecting with the T56, a conversion box is required

Clear as mud?

 

Yeah pretty much lol now bear with me on this, since the t56 is next would it be wise to just throw the converter box in instead of doing a bypass? If the bypass isnt something I have undo later ill just do it, my ultimate goal with everything is to prevent un doing my work ya know?

Also as a side note where could I find a pin out of the interior harness connectors for 89 and 90? I wanna make sure theres no difference and I can just plug into my current one, if not re pin it, would that link you gave me to austin thirdgen have them?

Thanks for all your help pocket I know how it can be aggitating explaining things when someones not quite on point

 

To bypass the buffer box, you unplug it and connect pins C and F. This can be accomplished by using a short piece of wire bent into a U and stuck into those pins. Hardly permanent and irreversible

http://www.austinthirdgen.org/mkport...SS_V8_vinE.jpg

Regardless, youd need to modifiy the wiring for the box later. Been a while since I looked at one but IIRC the high signal was teed into, low signal grounded, buffer box ignored completely, and output signal spliced to the cluster feed. Dont take that as 100% because its just off the top of my head

Which interior harness connectors are you looking for? If you plan to just plug in a 90-92 harness to an 89 car, there are pins to switch. Yes, check ATGO

 

Here u go ...