Chevy Z71 5.7 EFI->Vortec heads-CFSI-BlackBox PCM conversion. Trans wiring problem((

[Aksl]

Hi there everyone,

So I have now a problem with hocking up my automatic transmission 4L60E I believe, on my 1990 Chevrolet Silverado Z71 5.7 EFI, to my new setup of Vortec conversion withe vortec manifold and CSFI spider injector system and BlackBox PCM. The thing is, my transmission has only one 4 pin connector with 3 wires (one empty), out of the case. And a speed sensor in transfer case (since it is a 4wd vehicle).

So i have a wiring diagram for 1990 Chevy pickup K1500, ECM unit pinout chart for it as well.

I as well have pinout chart for 1996-1999 Vortec BlackBox PCM, Tahoe 5.7 Vortec wiring diagram. (it if the donor I used for my conversion).

Still cannot really be sure, where I should connect the 3 wires from the trans case to. In addition, the 2 wire from the speed sensor, since originally the go to the digital ration adapter.

If anyone has such experience or knowledge, please help and share. Thank you guys, I have been building up this project for three years now, has a lot more to do on it, but at least now the track is ready to run, can’t wait to finally take it out to the road.

[skandolis]

I dont have all the answers (or any for that matter) but it seems when i had a vortec in my el camino (with black box) i still had to use a drac (vss buffer)...(had third gen camaro guages so i used the buffer box behind the speedo) IIRC i took the parking pawl from a late 4l60 and swapped into my 700r4 in order to use the prndl switch from a 98 4l60e .....(maybe you don't need it?) i believe you would want to use the speed sensor in the transfer case (final drive and all) the four pin connector on the trans will be converter lockup control, there may be better ways now,but we just left the lockup control mechanical, wired through the brake switch and a vacuum switch. had to turn off a couple trans codes too ........ (the black box puts out a pwm signal for lockup, no good with 700r4 converter), im sure more knowledgable folks will chime in soon... Good luck, sounds like a fun project.

[Aksl]

Skandolis - i just understood what drac is, could you please specify what IIRC is please?

[Gojira94]

IIRC is "If I Recall Correctly." i.e. something remembered.

Programming your black box PCM, you want the PCM to ignore the auto transmission, as if there were a manual transmission installed. GM cars that have auto/manual versions have programming provisions for both, but with a manual, the only PCM interaction with the transmission is with the VSS in the tailshaft. An example is the F-Body car line from 1993-2002. I have 2 94 F-Bodies; one manual, one auto. They both have provisioning for auto trans features in the PCM's programming. The manual only sends output shaft rotations as electrical pulses which the PCM calculates against the wheel rotations per mile for vehicle speed.

It is not uncommon to do a manual lockup switch for the torque converter/ TCC lockup solenoid. Your 3 pins to your transmission I'm guessing are power, ground, ECM (PCM) signal.

[Aksl]

Ok, thank you for info
Now it starts to get more clear. So for the truck and pcm to stay still when I apply brakes, an have stable engine running I need to install the rrndl from a later model with 4l60e.
And connect the speed sensor through the drac to pcm, just need to know which plug and pin.
If I got it all right, if not please correct.

Thank you!

[Aksl]

Hi again everyone, thank you for your help once again!

Now I have a question of recommendation, what would you recommend me for my truck, should I live the 700R4/4l60 transmission and make all the changes for it to function, or should I install the 4l60E transmission in ?

[Aksl]

I dont have all the answers (or any for that matter) but it seems when i had a vortec in my el camino (with black box) i still had to use a drac (vss buffer)...(had third gen camaro guages so i used the buffer box behind the speedo) IIRC i took the parking pawl from a late 4l60 and swapped into my 700r4 in order to use the prndl switch from a 98 4l60e .....(maybe you don't need it?) i believe you would want to use the speed sensor in the transfer case (final drive and all) the four pin connector on the trans will be converter lockup control, there may be better ways now,but we just left the lockup control mechanical, wired through the brake switch and a vacuum switch. had to turn off a couple trans codes too ........ (the black box puts out a pwm signal for lockup, no good with 700r4 converter), im sure more knowledgable folks will chime in soon... Good luck, sounds like a fun project.

Hello skandolis, thank you for your help! So where am I at now, I connected the prndl switch to the underhood wiring, switched it to D, and it seems that now I got rid of the problem with truck trying to pull all time while I apply brake. I will make an adapter to install the switch to the axle out of the transmission, because if I instal the axle to the gearbox from later l460e, I will have to change all the switching gears system, changing it to cable instead of my, that uses rods.
I didn't yet find the drac, and don't yet know which pin to connect it to in my blackbox pcm when I will, may be when I do that I will get rid of problem I have now, may be you can confirm that my issue now is due to drac not connected. So the issue is, when I drive, and apply brakes and stop, the engine starts to loose idle and work unstable, like it's gonna go off, but it doesn't, it just like seem to choke. Can the issue be that drac not connected to my pcm cause this happening?

https://youtu.be/U51Qe9hKwdc

You can hear how it chokes on the video by the YouTube link above..

[LRT]

my automatic transmission 4L60E I believe, on my 1990 Chevrolet Silverado Z71 5.7 EFI, to my new setup of Vortec conversion with ... BlackBox PCM. The thing is, my transmission has only one 4 pin connector with 3 wires (one empty), out of the case. And a speed sensor in transfer case (since it is a 4wd vehicle) ... where I should connect the 3 wires from the trans case to. In addition, the 2 wire from the speed sensor, since originally the go to the digital ration adapter

The transmission is a 700R4, not a 4L60E. The 4 pin connector (with only 3 pins used) was for the TCC Lockup. A 4L60E has a 20 pin connector (with 13 pins used). The Blackbox PCM won't control just the TCC Lockup. You either need to install an actual 4L60E transmission, or for the purposes of the PCM, treat the current transmission as if it were a manual transmission.

[Aksl]

Thank you both, for a quick reply. And thank you for correcting and specifying the transmission model, i could not find this info.

- Ok, so let me clear out a few things, and get a more clear support from your side. Now when i am in driving mode "D" and i have my brackes pressed, the PCM doesn`t see that I`m in "D", so the car whants to roll, but since I`m pushing brackes and don`t let it roll, the engine is allmost shuting of, lowering and puting up the rpm, so the rpm is unstable. I thought is becouse of speed sensor not connected and transmission, now as I understand it has nothing to do with that, i gues i have to connect something from the dash (gear shifting mechanism neer the dash) to the PCM to fix that, do you know something about it, can you give an advice or some info?

- Ok, you made it clear for me that the blackBox PCM can not only controll my TCC Lockup, and that i can treat the current transmissiom as a manual one. So i have a couple of questions:
1. I don`t realy have a clear picture of what TCC Lockup does, do i need it in normal driving for automatic transmission to make correct gear shifting up or down, or is it used to transfer torque or power to the front axis when i put 4wd. If i only need it for 4wd, than i`m fine with that, just then were do i need to plug it for power, and from wich wires do i need to make a switch for it to work?
2. The speed sensor from the trans case, shall i conect that somewhere, since the all af the transmission generations have that, so i gues i shoul not let it out, and plug it as well, but the question is, should i plug it directly to the PCM (BlackBox), or through the digital ration adapter, as on my wiring diagram? and in eathe way, what wires should go where? ))

Thank you in advance!