Yes, blame GM for that one, lol. They called them DRACs or VSSBs in different years and models. Most people with TBI vehicles seem to call them a DRAC.Originally Posted by dale
Yes, blame GM for that one, lol. They called them DRACs or VSSBs in different years and models. Most people with TBI vehicles seem to call them a DRAC.
94 Blazer, Turbo'd 350 TBI - DD
1991 2500 Suburban Adventure truck - 4wd conversion, 4-link F/R, 582ci CNP Big Block with Terminator X EFI backed by a 6L90 and twin stick'd NP205 t-case
2012 Porsche Panamera Turbo - Date night car :)
1979 16' Action Marine/"Johnny Cash" Merc Bridgeport Champ Motor - Metalflake Maniac
The "White Box"
1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
-= =-
Yes the vssb is also known as a drac module. Thats what i learned at as. And vehicle speed is kinda important to proper fueling and spart timing. Trust me on this. Had a pickup that would stumble and or die when coming to a stop, fixed the vss signal and all is well.
If it don't fit force it, if it don't force fit f&%@ it!
My diagrams call is a VSSB, so that's what I'm calling it
I know the speed reading effects a lot. I've played with some OBD2 tuning. But I just want it to get a reasonable reading. But Ive also thought this evening. Since I will need to get a mechanical speed reducer to make the reading in my dash correct. If I screw that inverter in after that, wont it be close for the ecm?
Correct me if I am wrong, but I thought the 4L60E, and 4L80E both put out a 40pp(revolution) signal to the DRAC/VSSB, which converts that to all of the required signals for PCM, Cruise, RWAL, etc. Notice that Pins C7, C12 are inputs and C13 is a 1:1 signal (40ppR) on a single line. What PCM are you using? Can you set the Flag "Vehicle Speed Not From DRAC"? If so then you don't need the DRAC/VSSB and can send the 4Kppm directly from the sensor to the PCM.
Last edited by gregs78cam; 10-31-2013 at 02:39 AM.
1978 Camaro Type LT, 383, Dual TBI, '7427, 4L80E
1981 Camaro Z-28 Clone, T-Tops, 350/TH350
1981 Camaro Berlinetta, V-6, 3spd
1974 Chevy/GMC Truck, '90 TBI 350, '7427, TH350, NP203, 6" lift, 35s
Greg, i believe your theory should work. But be prepared for smoke just in case ;)
If it don't fit force it, if it don't force fit f&%@ it!
My understandings from reading the lovely web, was that it was 40ppm tell they went to the 4l60e, then it changed... and that's what I cant find.
Also, that whatever pcm I am using(I forget at the moment) could take a 2000 strait from a vss (assuming axle, tire, gear ratio, etc etc did provide a true 2000).
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