Need help merging together wirings of 1990 5.7/350 in cabin with 1998 5.7 vortec eng

[Aksl]

drac.jpg

Maybe it's possible to split / splice the VSS into two signals (4 wires)? Have two wires to the DRAC / VSSB to operate the Speedometer and have two wires for the '0411 PCM?

The DRAC / VSSB uses 40 Pulses Per Driveshaft Revolutions (PPR). The DRAC sends the speed signal to the speedometer.

The '0411 uses 40 Pulses Per Driveshaft Revolutions (PPR).

dave w

Hello Dave,

Thank you for reply,

Previously, before i got a new 1998 wiring, becouse the first one i got for free was all cut here and their, i tried splicing in in to the vss two screwed together wires ppl/wht&GRN/black, and connecting to Drac, and what happend is the speedo did not work and the 0411 did not see the vss. That is why i`m thinking of a solution, becouse this schem did not work unfortunately....

Got to find other solution, people say to wire the C50 GRN speed out of pcm wire to speedo directly passing the DRAC, but Cruise uses DRAC on older vehicles and abs as well, i wonder if these modules can use the C50 signal out of PCM as well...

If the DRAC sends 4k to Cruise, as the schem you have attached sayes, i can wire the it from C50 0411 speed signal, what wories me is that the speedo it says uses 2k at some vehicles..

Thank you.

Sincerely.

[dave w]

I've successfully split the 4L60E 40 PPR for both a '0411 PCM and Dakota Digital Electronic Cable Drive Speedometer Control Unit ECD-100: http://www.dakotadigital.com/index.c...rod/prd886.htm

Maybe the Dakota Digital SGI-5E will be a solution: http://www.dakotadigital.com/index.c...rod/prd126.htm

Perhaps the SGI-5E has the ability to supply multiple outputs from one single 40 PPR (VSS) input; which would eliminate the need for a DRAC?

Additional information on the SGI-5E http://www.dakotadigital.com/pdf/SGI-5e.pdf




dave w

[Aksl]

Thank you Dave,

Yeh i gues with the Dokota Digital SGI-5E, you can 'not splice to the vss wires' but plug them to the Dakota module, and from there everywhere else PCM, Speedo, ABS, Cruise, and set each one at pulses they need. That is an interesting module, can`t say it costs a lot, it doesn't, but i know people manage to connect all that from the C50 0411 PCM pin with speed out signal, i just have to find out how. If i dont manage to, i will surely be using your solution with Dakota module.

Thank you for your help!

[lionelhutz]

The VSS sensor signal should be capable of driving both inputs. I'm thinking you're just seeing a ground issue between the circuits. I'd try connecting only the high side of the VSS to the DRAC. That should be pin 21 on the '0411 to pin C12 on the DRAC picture Dave posted. Both should be ppl/wht wires.

If that doesn't work, then ohmmeter the VSS wires into each module and see which ones are connected to the ground terminals.

The ppm for each signal is listed on the DRAC pictures. Speedometer is 2000ppm, cruise is 4000ppm and the RWAL is 128,000ppm. So, the speedometer would read double and the RWAL would not work if you used the VSS output on the PCM. You could fix the speedometer with a frequency divider circuit, but the RWAL would be lost.

[Aksl]

The VSS sensor signal should be capable of driving both inputs. I'm thinking you're just seeing a ground issue between the circuits. I'd try connecting only the high side of the VSS to the DRAC. That should be pin 21 on the '0411 to pin C12 on the DRAC picture Dave posted. Both should be ppl/wht wires.

If that doesn't work, then ohmmeter the VSS wires into each module and see which ones are connected to the ground terminals.

The ppm for each signal is listed on the DRAC pictures. Speedometer is 2000ppm, cruise is 4000ppm and the RWAL is 128,000ppm. So, the speedometer would read double and the RWAL would not work if you used the VSS output on the PCM. You could fix the speedometer with a frequency divider circuit, but the RWAL would be lost.

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Hello Lionelhutz,

Thank you for your input, i`m not sure i have the DRAC on my truck, haven`t found it, it seems that I don`t have it.

I was thinking of changing the RWAL module to a full 4 wheel ABS module of the same 1998 Tahoe i got the wiring from, and getting the hubs, sensors, and sensor plates for the front wheels. Then i gues i will be able to use the PCM C50 speed signal to run it...

Before i have paralleled the VSS signal right out from the sensor to PCM and speedo, and unles i dropped one of either of them would work, i will try using just hi side, all thaw, i have to measure, in my 1990 schematics the Hi signal is YEL (not PPL/WHT) and on the 1998 Hi is PPL/WHT, that is where the problem could have been hiding, that is probably the reason the cluster didn`t work in parallel with PCM...

I will try connecting the wiring back to the vehicle this weekend and see if it all works out fine or not, i`d bother splice to connect the speedo at the fender, under the hood, then splicing in under the car at the trans...