4.3 PCM Pinout and VSSB/DRAC Wiring

First post but I've been using this forum as a resource all winter while doing my swap of a 1993 4.3 CPI (W Vin) out of an S10 Blazer into the my 1986 Toyota 4 runner. I did all the harness stripping myself using diagrams I found on google (mostly autozone).

In the final stages of this swap and test driving it, when I discovered the trans wont shift. I have ALDL Droid so I can see I also dont have "RAW OUTPUT SPEED" and "Vehicle Speed". They both read 0. So I started digging and it turns out I never swapped over the DRAC/VSSB and I cut all of that out of the harness. Stupid me... I know.

So I bought one off ebay that says its for a 95 tahoe. I made a few assumptions that this will work because its an early 4L60e as well and its a 7 pin not a 14. I've been using this reference for PCM Pinout (https://troubleshootmyvehicle.com/gm...in-out-table-2) and the F-12 and F-13 match the colors (BRN and DRK BLU) for the wires the DRAC/VSSB I bought for "Trans Output Speed" and "VSS Speed". So straight forward right? NOPE

I went to install the DRAC/VSSB last night and my F-13 is BRN (not DRK BLU) and my F-12 is BRN/WHT (not BRN). The diagram from autozone's site doesn't show F-12 at all but calls F-13 out as BRN (correct to my vehicle) and connecting to the VSSB. So I hooked up the BRN wire from the VSSB to F-13 last night and still no speed. Not surprising.

I also found this awesome repair bulletin (https://atracom.blob.core.windows.ne...ear/atb302.pdf) that said its applicable to S-10's and Jimmys 93-95 but has F-12 and F-13 as DRK BLU and BRN.

I'm pretty sure the issue is most this literature is for the TBI motors and mines a bastard so I'm coming up empty handed in my search. Should I trust that the pinouts of the PCM's didn't change (because why would they print a different board for such a minor change in the fuel system) and ignore the wire color? Doesn't anyone have a comprehensive PCM Pinout for a W Vin CPI motor?

Any help would be seriously appreciated. I have a trip coming up next weekend and I'd like to have more than 1st and 2nd gear.

Maybe the information in this thread will help: http://www.gearhead-efi.com/Fuel-Inj...Information-0D

dave w

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Originally Posted by dave w

Maybe the information in this thread will help: http://www.gearhead-efi.com/Fuel-Inj...Information-0D

dave w

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Thanks for the link, I have read through that and I dead ended.

It says A10 to F13 BRN wire is "VSS NOT FROM DRAC SET" Not sure what that even means. My F13 is BRN, but the diagram I have shows speed into it FROM the DRAC. And, the BRN wire from the DRAC into F13 is what I did.

So I drove around the neighborhood with the brown wire (C13) from the DRAC connected to the F13 pin on the computer no shift, no speed. Did another few laps with the Blue wire (C11) hooked into the F13 pin... No shift no speed.

Hooked an ohmmeter up between the two VSS pins and got resistance at stop and OL at 10MPH which I think means it's doing it's thing.

I have power and ground to the drac. I did hook up a voltmeter to the Blue and Brown wire off the DRAC and got no output. I think I read you're suppose to get 5-7V out of those?

I've been reading nonstop, and I'm starting to second guess I bought the right DRAC/VSSB or installed the right reluctor ring onto the output shaft

I have a 93 4.3 Vin W out of a S10 Blazer and the F12 is Brown and F13 is Brown/White. The tag on the DRAC as large letters CBJ but the part number is not readable maybe last 4 are 4375???

Here is a document that shows how the speed sensor and drac connect to the ECM. There are diagrams in this document which tell what each pin is on the drac.

Hope this helps.
Brian

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Originally Posted by 4.3JeepYJ

I have a 93 4.3 Vin W out of a S10 Blazer and the F12 is Brown and F13 is Brown/White. The tag on the DRAC as large letters CBJ but the part number is not readable maybe last 4 are 4375???

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My F13 is brown and my F12 is brown/white haha. What a mess. What color wires come out of your DRAC? If you did the swap do you maybe remember if the DRAC did in fact connect to both F12 and F13? My diagram only has F13 listed

I found this thread when searching for more info
http://www.gearhead-efi.com/Fuel-Inj...Information-OE

Is it safe to say all computers with the same service number will have the same pin out? I know the PROM can change what i/o's do, but did GM do that?

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Originally Posted by tgelles

My F13 is brown and my F12 is brown/white haha. What a mess. What color wires come out of your DRAC? If you did the swap do you maybe remember if the DRAC did in fact connect to both F12 and F13? My diagram only has F13 listed

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My lysdexia switched what I meant I thought I said. F12 is brown and white, F13 is brown. We must have the same diagram mine only shows F13 to the PCM.

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Originally Posted by 4.3JeepYJ

My lysdexia switched what I meant I thought I said. F12 is brown and white, F13 is brown. We must have the same diagram mine only shows F13 to the PCM.

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You gave me the confidence I needed to hook up a wire I wasn't sure what it did into the PCM. Well it worked. So thank you very much.