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1990-91 *factory* wiring schematic...anyone?

dyeager535

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I'm SURE I've seen links posted on here before, but I couldn't find one.

I need the factory one so *hopefully* the VSS is "explained" like it is here: Example Diagram

Making slow progress on the 1991 465/205 swap, which of course means no speedometer cable, which means I'm going to use the '91 Instrument cluster I have.

Anyways, for clarity, I am needing to compare the output of the 205 VSS to the above diagram, since it looks like the easiest path to do the swap in all regards might be to get away from MAF, and use the '730 SD ECM, which as the above diagram shows, has an output for the Speedo, and cruise if I want it.

Only thing I'm not absolutely clear on yet, is if I can re-program the PROM to get the speedo to read correctly. It doesn't appear it's that easy, but wiring in the DRAC isn't painless either, and is just more wiring and things to go wrong. I may anyways though, because if I can get a diagram that pins out the DRAC, I should be able to determine what the ECM sees for pulses from the DRAC, and whether that will work. I'm really unclear on that last part, because it's a 40 tooth reluctor ring, which is a lot more than the early two puls cable drive system, which is what the '165 MAF ECM uses, which is what I have.

Only problem with using this system on a truck is that thirdgen.org doesn't like you talking about trucks. :(
 
I have the wiring diagram but I can't put my hand on it right now. The drac is modifable? for the the different gears and tire combo. Look for the post I made here when I done the nv4500 swap on my truck. I used the 90-91 dash in my 80 model dually to get the speedo to work. It isn't that bad of a swap if you have the wiring diagram.
 
Thanks for offering info on the DRAC, but I need to know what the actual outputs are...the problem is that the ECM is looking for a particular signal. (whether 2 pulse, 2000 pulse, 4000 pulse per mile, or something like 1 pulse for every .7 inches, if I've got it right)

Since I'm not using a 90-91 truck ECM to control my injection, using the DRAC is probably not an option, unless I change to some other ECM. Apparently trucks were the only ones to use the DRAC, except some of the mid 90's cars, but they use a USSB or something like that. Similar, but not the same I guess.
 

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