VPC Install

[blk92suprat]

I just want to confirm my information is correct as well as ask a few questions on the areas that are a bit fuzzy to me.

Car- 92 7mgte

So I have a VPC that I will hardwire in conjunction with the safc2.

VPC wires...
Red- Power
Black- Ground
White- Ignitor
Brown- NOT USED, for FCON
Gray- What is this one for??? Air temp sensor?

In order to run the vpc>safc>ecu... I will need to run the vpc yellow wire into safc input wire (orange), then safc output (pink) to ecu side.

Here is my confusion.....I dont understand why the vpc yellow wire is not in the same harness with the above colored wires. The vpc yellow wire is in the sensor harness? Can someone shed some light on this?

Anything else I should know about?

Thanks alot guys!

 

[martin p]

Plus you need to fit a 2.4k ohm resistor into the ecu loom as per picture it can be fitted at ecu end or at the AFM plug

 

[blk92suprat]

That helps alot. Thank you.

Is the resistor absolutely necessary?

I just have to shave the insulation off the E2 and THA and add a wire with a resistor in place?

 

[martin p]

That helps alot. Thank you.

Is the resistor absolutely necessary?

I just have to shave the insulation off the E2 and THA and add a wire with a resistor in place?

yes you need the resistor, just shave some inslation off both wires and solder the resistor between them and insulate well. job done.

The diagram and resistor set up is for a 89-92 car.

 

[blk92suprat]

Thanks for your help.

Its funny how the plug n play harnesses went for $450 when all you have to do is splice 4 wires...

Thanks again man..much appreciated!

 

[MarkIII4Me]

Isn't the yellow VPC wire the air pessure input from the VPC's pressure sensor? So if you wire the SAFC into the yellow wire, then you a basically wiring the SAFC into the pressure sensor, having the SAFC clean up the pressure sensor signal before the VPC converts it to Karmen.

I'm certain the grey wire is the VPC Karmen output since I have the pnp harness and the grey wire on the main side connects to the TCCS MAF wire which is green/red and is wire KS on the factory harness.

If you want to clean up the VPC's Karmen signal, wouldn't you want to splice the SAFC's orange and pink wires into the VPC's grey wire (output) instead of the yellow wire (input)? This way the VPC has already converted the signal from pressure to Karmen and the SAFC will clean up the Karmen signal.

Which is better to do? Run the SAFC inline (in pressure mode) with the VPC pressure sensor input to the ECUor run the SAFC inline (in Karmen mode) with the VPC's Karmen output to the ECU?

I'd really like to know this too since right now I have my SAFC2 wired into the grey VPC Karmen output into the ECU MAF wire.


*EDIT*

I guess martinp's post answers my question. Grey wire it is. I didn't know about the resistor however. What purpose does it server, and why is it only needed on 89+ Supe's?

 

[MarkIII4Me]

Wait a minute; I'm fairly certain the VPC's PnP main harness already has that resistor in place.

 

[martin p]

Isn't the yellow VPC wire the air pessure input from the VPC's pressure sensor? So if you wire the SAFC into the yellow wire, then you a basically wiring the SAFC into the pressure sensor, having the SAFC clean up the pressure sensor signal before the VPC converts it to Karmen.

I'm certain the grey wire is the VPC Karmen output since I have the pnp harness and the grey wire on the main side connects to the TCCS MAF wire which is green/red and is wire KS on the factory harness.

If you want to clean up the VPC's Karmen signal, wouldn't you want to splice the SAFC's orange and pink wires into the VPC's grey wire (output) instead of the yellow wire (input)? This way the VPC has already converted the signal from pressure to Karmen and the SAFC will clean up the Karmen signal.

Which is better to do? Run the SAFC inline (in pressure mode) with the VPC pressure sensor input to the ECUor run the SAFC inline (in Karmen mode) with the VPC's Karmen output to the ECU?

I'd really like to know this too since right now I have my SAFC2 wired into the grey VPC Karmen output into the ECU MAF wire.

Mines wired exactly as per that diagram except I've fitted the resistor at the ecu end of the loom. But I'm not using a safc, the safc does clean up the output for the Vpc I would keep it set as per the diagram I posted up, personally.

Maybe someone with more experience with these piggyback unit's with be able to help more.

the wires shown in that diagram are the ones you need to connect into the cars' loom, it doesn't show the pressure sensor wiring or the ait wireing as they should be staight forward as they plug in to the Vpc via a multi plug.

also just to point out you MAY still hit fuel cut with the vpc it depends on which pressure sensor it has, i had a 1bar sensor and was hitting a lot so i managed to get a 2bar one, i Think there is a 3bar one around too,

They are 0-5v sensors So a Gm 3bar one should work,according to info on this forum.

 

[martin p]

Isn't the yellow VPC wire the air pessure input from the VPC's pressure sensor? So if you wire the SAFC into the yellow wire, then you a basically wiring the SAFC into the pressure sensor, having the SAFC clean up the pressure sensor signal before the VPC converts it to Karmen.

I'm certain the grey wire is the VPC Karmen output since I have the pnp harness and the grey wire on the main side connects to the TCCS MAF wire which is green/red and is wire KS on the factory harness.

If you want to clean up the VPC's Karmen signal, wouldn't you want to splice the SAFC's orange and pink wires into the VPC's grey wire (output) instead of the yellow wire (input)? This way the VPC has already converted the signal from pressure to Karmen and the SAFC will clean up the Karmen signal.

Which is better to do? Run the SAFC inline (in pressure mode) with the VPC pressure sensor input to the ECUor run the SAFC inline (in Karmen mode) with the VPC's Karmen output to the ECU?

I'd really like to know this too since right now I have my SAFC2 wired into the grey VPC Karmen output into the ECU MAF wire.


*EDIT*

I guess martinp's post answers my question. Grey wire it is. I didn't know about the resistor however. What purpose does it server, and why is it only needed on 89+ Supe's?

the Resistor corrects the temp part of the arm signals i think? not 100% sure on that.

Its needed on all years BUT the PRE 89 cars Need 3 resistors fitted NOT 1 due to the HAC(sp or similar) being external to the ecu? I have the pre 89 info too and a pre89 pnp harness but the resistor's have been removed.

Wait a minute; I'm fairly certain the VPC's PnP main harness already has that resistor in place.

Yes they do,

 

[blk92suprat]

Just to confirm, the afm wire is cut with the ecu side plugging into the safc output (pink).

Is the other side of this afm wire just capped off since we are no longer using it?

 

[martin p]

Just to confirm, the afm wire is cut with the ecu side plugging into the safc output (pink).

Is the other side of this afm wire just capped off since we are no longer using it?

Yes the K/S signal(afm) wire is capped off on the engine side of the loom and the pink(safc)wire goes to the ecu side.

Don't forget the resistor between the E2 and tHA wire.

 

[blk92suprat]

Yes the K/S signal(afm) wire is capped off on the engine side of the loom and the pink(safc)wire goes to the ecu side.

Don't forget the resistor between the E2 and tHA wire.

Thanks again, install was a peice of cake.

Your diagram was super useful. This thread should be stickied since info on this isn't very abundant.

 

[super.secret.supra.club]

where does the orange wire of the safc go to?