Rb26 Pfc Working On Rb20/rb25

[The Mafia]

Hi Guys,

I have a R32 GTS-t in the workshop at the moment, I was originally going to supply him with an AP PFC, however the one supplier I know that has one wants to sell it stupidly

expensive ($2300). I have converted a GTR RB26 PFC for him, I only just got it going, it seems to be working fine. Im going to tune it today, ill let you know how it goes. I can

definately say it is 100% possible.

paulr33, im looking into the R33 schematics at the moment for the VCT, if I have any info on it ill make sure I let you know.

Cheers

Rob

Rob,

You're a f**king legend.

Thank you so much for getting involved.

[paulr33]

hi rob,

yeah it was nick, i spoke with him last night.

i would like to see the car running just to confirm a few things for my loom.

do you see any issues in me looking (and copying) the base tune date once you guys have done the base stuff?

i am interested in base injector, airflow ramps and stock maps. i can generate them myself if need be.

is he using gtr injectors or stock rb20 ones

[KURAUN]

paul using stock rb20 injectors atm...

Car is running fine atm no probs but will see with a few more days of driving, but so far so good.....

And thanks again Rob and Danny at CREATD.....legends

[paulr33]

my battery gets fixed wednesday

[Mrlag]

Look forward to seeing these looms poping up on the market will be wanting asap.

[S13 SecaBoy]

any idea on how soon there will be one available for an rb20??

if its only a few weeks, then i wont bother trying to find a stock r32 ecu...

please let me know on a ETA...

[paulr33]

there is no ETA. please be patient. my car gets fixed today so i can actuall test and try stuff.

i have the 26 FC at home and my R33. we have come across another potential issue with the 02 sensor setup

as the GTR doesnt run heater but the 32/33 GTST does so it may not work, that is there may be no 02 feedback

[S13 SecaBoy]

okay, fair enough....

good luck with it, and i'm still interested in it once its done...

[The Mafia]

don't worry, I'm nudging him

I have a powerfc pro here for a GTR that I want in my car asap.

Cubes, Paul also send me your Loom comparison excel spreadsheet. Done well.

Paul, its got to work, because the AP engineering guys obviously worked it out. Maybe a AP engineering ECU as reference to see what they did?

[paulr33]

the ap eng FC is the older style RB25 PFC with VCT switch remove (and wire), 2 injectors flipped and some map changes. the rest is the same

[The Mafia]

I thought they did it with the RB26 ecu's?

hhmmm.

We'll have to keep on it.

[paulr33]

no they grab the older style 25 PFC

it runs 2.3 i am pretty sure and uses N001 hand controller

they edit the internal version, change the map data, injector flip, change the afm ramp and inj settings and remove VCT

[Cubes]

Hey paul,

I've been double checking a few things and the fuel pump flow control has stood out as being a problem.

First up how the fuel pump is controlled by the GTST's.

The GTST's essentially run a basic dropping resistor and relay (they call fpcm) that is activated by the ecu to earth the pump out and bypass the dropping resistor resulting in high voltage to the pump.

The R33 and R32 GTST ecu's have pinout 104 activated constantly which is why we loose the high/low function with a pfc in the gtst's.

The GTR's do away with the dropping resistor in favour of 2 ecu pinouts for the high/low control and a 'real' fpcm (fuel pump control module). Essentially the fpcm is a relay thats earthed and resistor thats earthed all in one. It receives a signal from the ecu via pinouts 104 or 106 and activates the associated circuit. One being the straight relay earth the other being the resistored earth.

So whats what?!?!

We really need to remove pinouts 104 and 106 and see what they are doing. I would assume as the fuel pump goes high one is off the other is on and as the fuel pump goes low its vice versa.

Which will cause problems with fuel pump control on both prime and running.

----

I think the answer is maybe one or both of the below.

1. Simply bridge ecu pin outs 104 and 106 so the gtst's relay (fpcm) is always active.

2. The fuel pump receives its voltage via a relay that is activated by the ignition switch and the ecu earthing out. So simply splice in to the fuel pumps voltage feed and using it as a trigger for a negatively earthed relay.

When the ignition key is turned the ecu earths its self out activating the new negatively earthed relay; as the fuel pump is now earthed it will run.

I would hope it doesn't cause problems with prime. I would assume not going by the wiring diagrams.

I've pulled the wiring diagrams out of the engine manuals; next time your on msn i'll send them on over to you to have a look.

[paulr33]

thanks for the info, i am reluctant to try anything more at the risk of frying my car of the FC itself

i tried it last night, had a constant reboot cycle on the car and hand controller and the fuel pump kept restarting

created; what did u guys do for fuel pump control ?

[Cubes]

When I do this I will be disconnecting fuel pump, ignitor, afm, o2 and anything else I can think of at the time.

[paulr33]

i am no longer doing this project. i tried it last night and was faced with some possible big risks so im not prepared to continue.

i will sell my 26 FC and the loom adapter if anyone wants to continue or use it for other purposes.

the loom adapater is an inline adapter for Rb26 or Rb26 or Rb25 to Rb25

we have cut all of the other excess junk from it so it suits rb25, all of auto signals have been cut so its only manual loom

[paulr33]

ecu is for sale here

http://www.skylinesaustralia.com/forums/in...howtopic=169959

anyone interested in the loom?

it can be used for any type of inline patching or hacking etc

ive gone and cut all the auto and non related wires to suit rb26

[The Mafia]

hhmmm.

So close.

paul, are you able to post up what I emailed to you today as a reference, I don't have a copy anymore. Just about the bridging of the two fuel pump signals and my explaination.

[The Mafia]

oh, and can you move this back to the forced induction section so that we make pick up from where you left off?

[Interloper]

paul using stock rb20 injectors atm...

Car is running fine atm no probs but will see with a few more days of driving, but so far so good.....

And thanks again Rob and Danny at CREATD.....legends

Hey Nick, hows the car running?

are you able to get good economy out of it?