computer / tbi / 4l80-e info help

[sweetk30]

i have a 87 tbi system in the truck now with all 87 parts. was c10 donor truck with 350 auto 700r4 and non a/c .

i have a few computers from 93 and 94 g30 1ton vans with 350 and 4l80-e in them. worked when pulled.

i also have a stand alone harnness with custom burnt chip from a place years ago that let me run this with 4l80-e via piggy backing few signals from stock tbi.

so basicly you get 2 computers in the vehicle .

i am looking to redo the setup and there was someone here that does update harnneses or modifyed stock harnness.

if i got the harnness out of the truck fro tbi and the stand alone unit and newer than 7747 computer is there a cost effective way to make it all one and work for my needs ?

 

[eagle mark]

Yeah but I'm a little lost, what is the final setup? 4L80e trans?

You'll want to run the 16197427 or 16196395 PCM with an $0E mask for the 4L80e trans. The TunerPro definition files are here:
http://www.gearhead-efi.com/Fuel-Injection/showthread.php?337-16196395-PCM-Information-OE
There's some hacks in there to run 700R4 as well.

You can do the changes to your harness in the 1987 truck to newer PCM. Dave W did a writup about it here:
http://coloradok5.com/forums/showthread.php?t=270253

There's also some updated info here:
http://www.gearhead-efi.com/Fuel-In...ersion-PCM-Swap-with-Wiring-Pinout-Directions

 

[sweetk30]

in the end i want tbi harnnes for better faster computer and also run the 4l80-e in 1 package.

 

[eagle mark]

Then it's all above.

You'd have to add the 4l80e wiring from trans to PCM along with the plug change to PCM from your harness.

There's not much other work, just removing the ESC becuase the knock Module is in Memcal with chip on the newer PCM. So knock sensor wire goes to PCM.

 

[dave w]

in the end i want tbi harnnes for better faster computer and also run the 4l80-e in 1 package.

I'm doing this exact thing this weekend. I'm working on a 1990 K3500 7.4 / TH400, that is being upgraded to a 16197427 PCM and the wiring for the 4L80E is also being wired. The donor transmission and trans wiring pigtail was from a 94 K2500 Suburban. I am wiring the new PCM exactly like a 94 K3500 with a 7.4 liter. So far I'm into the project about 4 hours and the truck is up and driving again. The first data log is done, and the second chip is burned and installed. I need to add the 4L80E wiring, including a brake switch wire for the Torque Converter. The 1990 K3500 is a TBI truck already, so the Vehicle Speed Sensor is already in the transfer case from the factory.

If you want more information, send me a PM.

dave w

 

[dave w]

Here are some pic's of the 4L80E harness I put together. The TISS and VSS are factory twisted wire pairs with a ground to suppress noise, good stuff to include in a 4L80E retro-fit! A few wires need to be connected inside the cab; ground, brake switch to power the TCC, and ignition power. This is a 4WD application, so I might need to add a TOSS connector also? The VSS is in the NP241. I'll also need to install the DRAC / VSSB. All in all, about 20 wires. The wire colors don't match, but the pin locations from the 4L80E to the ECM pin locations obliviously do!

dave w

 

[dave w]

More pic's of the VSSB / DRAC. TBI Chips has a good write up on the VSSB / DRAC here: http://www.tbichips.com/drac/

dave w

 

[Tnsejed]

I'm in the middle of doing all the wiring right now for this exact setup. Just like DaveW is..haha.

I'm running a 2wd G30 4l80e utilizing the 1996 motor as well.

1996 G30 1 ton van 2wd, 350 TBI with 4l80e into 1989 Blazer.

7747 to 7427 pcm.

Utilize existing blazer harness and repinout ecm harness to new pcm. Add in transmission harness an tcc circuit from brake switch. Remove VSSB harness from interior harness and splice into new transmission harness.

I'll be incorporating the VSSB into my transmission harness only.

TCC lockup circuit for the 1996 G30 shows Brake fuse > TCC/Brake Switch> Brake Transmission Shift Interlock Relay> PCM E13 Brake Switch input.

Also remove Ground 455 PPL from MAP sensor (g30 exterior harness run) and go directly from trans to PCM. Remove Batt feed circuit (pinout E on Trans connector) from injector harness (g30 exterior harness) and run to a batt feed on the blazer. (all G30 van runs as far as I know). This circuit powers the TCC solenoid, both shift solenoids, and 3-2 control solenoid.

I'm not utilizing any vss on the 241 as I have the input and output VSS on the 4l80e. This would be the difference from what it looks like Dave is doing.

 

[GMC Truck]

More pic's of the VSSB / DRAC. TBI Chips has a good write up on the VSSB / DRAC here: http://www.tbichips.com/drac/

dave w

dave, what do the little "dip switches" do in the DRAC module? I have never seen one opened up before....

 

[eagle mark]

Well there's a DRAC that has one set of jumpers and when you see one with 2 sets of jumpers it's a VSSB.

Dave installed the Dip switches so he can turn on or off each jumper. This is how you modify the DRAC or VSSB to correct VSS readings after a gear or tire change.

 

[GMC Truck]

Oh, so those dip switches are not there from the factory. Those are installed for calibration changes? Does that mean that the factory has "many" diffrent modules, cause the same truck could have 3-5 diffrent gear ratios available.

 

[eagle mark]

Yup, the stock one that comes in the truck has wires in certain spots. dip switch makes it possible to turn on or off that spot.

 

[dave w]

I'm in the middle of doing all the wiring right now for this exact setup. Just like DaveW is..haha.

I'm running a 2wd G30 4l80e utilizing the 1996 motor as well.

1996 G30 1 ton van 2wd, 350 TBI with 4l80e into 1989 Blazer.

7747 to 7427 pcm.

Utilize existing blazer harness and repinout ecm harness to new pcm. Add in transmission harness an tcc circuit from brake switch. Remove VSSB harness from interior harness and splice into new transmission harness.

I'll be incorporating the VSSB into my transmission harness only.

TCC lockup circuit for the 1996 G30 shows Brake fuse > TCC/Brake Switch> Brake Transmission Shift Interlock Relay> PCM E13 Brake Switch input.

Also remove Ground 455 PPL from MAP sensor (g30 exterior harness run) and go directly from trans to PCM. Remove Batt feed circuit (pinout E on Trans connector) from injector harness (g30 exterior harness) and run to a batt feed on the blazer. (all G30 van runs as far as I know). This circuit powers the TCC solenoid, both shift solenoids, and 3-2 control solenoid.

I'm not utilizing any vss on the 241 as I have the input and output VSS on the 4l80e. This would be the difference from what it looks like Dave is doing.

I wanted to update this tread with new information. The original 1990 K3500 VSS is needed by the instrument panel. The plan going forward is to use the use both TISS and TOSS from the 4L80E. The TISS is wired to the PCM, the TOSS is wired to the DRAC. The DRAC will provide vehicle speed to the PCM. The original wiring from the 1990 NP241 T-Case VSS will not be modified.

Reference Note:
The 1990 K3500 NP241 T-Case has a 40 tooth / per driveshaft revolution reluctor ring.

The 4L80E TOSS has a 40 tooth / per driveshaft revolution reluctor ring.

The wiring diagrams for the G, C, K vehicles vary, do the homework to get the wiring correct!

dave w

 

[Tnsejed]

You are correct Dave. It does pay to do your homework.

Also everybody you need to double check everything. I looked at that one spreadsheet referenced above and just double checked against my data and I see a few discrepancies. But this is of course predicted as there are manufacturing changes and sometimes 'short cuts' in the production line. So you need to use your factory diagrams and check against pinouts of the actual vehicle in your shop!

Take it FWIW... I only have 11 posts.

For the PCM to accurately control you're 4l80e you need to use the output VSS (TOSS, I always called them input and output vss: bad habit I guess) on the 4l80e and have it routed through the correct VSSB and input into the PCM. The VSSB will also need power and ground.

Without the VSSB the wave signal will be different. Now I have not scoped any of these parts so I can't tell you for certain what it looks like but this is my understanding of the unit.

Also For Information. The 1990 to 1991 K5's did use an electronic VSS in the transfer case. 1989 was mechanical from the 241.
For my purposes this is being ditched. I will run an electronic speedometer from the new VSSB C15 terminal (Lt blu/Blk on 1995 G30), if I feel like it .

 

[eagle mark]

Discrepancies in wiring can also be from year to year. 4L60e trans went through many changes. For instance one I am bumping into at the moment is 1994 has 11 pin plug and 1995 has 12 oin plug and the extra wire is a PWM TCC. Here's a guide for it.
http://www.impalassforum.com/vBulletin/showthread.php?t=269586

 

[dave w]

Here is a few pics of the progress. Wiring is done, now it's time to get the 4L80E. The DRAC input to PCM F13 will be installed when the 4L80E. The old VSS input is still being used with the TH400. Installed a relay for the brake switch input to the PCM. The relay is wired normally closed, so when the brakes are applied 12VDC is turned off to the PCM. To supply power to the 4L80E the use of add a circuit fuse holders are being used. I don't think using a stripped wire on a fuse is a good plan.

dave w