R32 Gts4 Microtech / Wiring Issue

[Swiper the Fox]

ok so thats on the attessa computer it self in the boot?

yep

[55yko]

ok i ran a tps feed round the outside of the car, from the grey microtech signal wire to the purple attessa wire. Had no affect. I checked that it was getting 0-5V in the boot. All the dash lights are still on!!!! HELP!

[blind_elk]

Advanced Engine Management (Wolf) have a "black box" solution for this problem. Maybe Microtech have one too.

I'll try and remember to check mine out tonight and let you know how the Wolf box works.

[55yko]

that would be great, but i think there is a bigger issue somewhere!

[55yko]

still got no idea, the purple wire / tps feed didnt work!

[bozodos]

was wondering if anyone could post their solution to this? i've tried looking up this and the fact that my VCT is not hooked up, and can't dredge anything up!

[55yko]

Still havent found a fix need one asap

[bozodos]

well after plugging in a manual RB20DET ECU into the original loom last weekend, the car spluttered and died, seemed to be the fact that its still all fully wired up, I am considering cutting all of the wires apart from the TPS and power wires, though I'd really like to not have to do that, so has anyone else found an alternative yet?

[bozodos]

ok well after Googling this problem, and coming back to a similar archived thread on here, I decided to link the throttle opening output and throttle sensor output signals together to try and get the TPS voltage to the ATTESA computer - when turned on, the light went out for one second and came back on.

Do I still need this buffer circuit as well, or should I try a diagnosis on the entire system in case there's something else wrong?

Edited February 8, 2009 by bozodos

[bozodos]

well after several hours of digging around in the archives, I found this quote from TO4GTR in another ATTESSA thread regarding a Microtech.

"yes after many headsrcatching sessions.

hears what it was all about.

tps adjustment to get .4volts

hooking up the attessa throttle wire to the microtech throttle signal.

unplugging the f**king air bleed conector"

the TPS wires mentioned in the Microtech manual are grey and brown, and on the wiring diagram, it has TPS 5v and TPS Sig pinouts, though I'm not 100% on which to use, im guessing TPS Signal to TPS output on the original loom.

Edited February 9, 2009 by bozodos

[bozodos]

Just attempted connecting TPS output from original loom to Microtech TPS Signal wires, STILL no luck!

can anyone PLEASE help me on this one - there must be at least one GT-R out there with both a working Microtech and ATTESSA system!

[bradkazz]

Hello I am researching the same issue for an ECU install.

So Far I have;

The ATTESA requires 0.4V to 3.5V TPS signal

The factory ECU has an inbuilt amplifier that generates the required signal.

When using an aftermarket ECU, that does not offer TPS out, the RB26 wiring loom requires modification to the wire connected to pin 56 TPS output signal. The wire at pin 56 needs to be cut off and T connected to pin 38 TPS input signal.

The TPS sensor needs to be manually adjusted to provide 0.4V when idling with the throttle closed.

Your Microtech should have three wires connected to the TPS

Ground

5V power

TPS Signal (connect to Microtech and ATTESA)

I have not tested this option, but provided my research is correct, you need to connect the wire that was originally connected to pin 56 to the TPS Signal wire on the Microtech and adjust the tps until it reads 0.4V at idle with the throttle closed. I beleive the ATTESA also requires an RPM signal which is generated by the factory ECU at pin7.

I intend to build a simulation amplifier and will post the design once complete

Edited February 23, 2009 by bradkazz

[bozodos]

Yeah I've already adjusted TPS at idle to exactly 0.4v with a multimeter, and then tried alternately connecting wires 56 and 38, then connecting wire 56 to the grey TPS signal wire on the Microtech - the other thing I should have done was pulled out my subs and amp and checked the error codes being thrown up by the ATTESSA computer to see if there was something else wrong with the system. The part I'm still unsure about is whether it definitely needs some sort of extra circuitry or whether joining the wires is enough.

(when I bought this car I was told that the standard computer need only be piggybacked onto the Microtech, stupid me for not getting the previous owner to test this out)

[bradkazz]

From what I have read, once the idle voltage is adjusted to 0.4v the Attesa will function, but becuase the ramp rate is not exactly as expected the system will apply more front bias at a lower throttle opening. An additional circuit should not be required, but it would make the system function exactly as intended.

Perhaps your issue is related to the tacho signal.

[bozodos]

even with it adjusted I just get a red light after startup, so its obviously not working at all, what do you mean about the tacho signal?

[bradkazz]

Some of the post I have read indicate that the ATTESA and ABS also use a tacho signal, the factory ECU outputs a tacho signal from pin7. I assume you will need to connect the Microtech tacho out to this same wire.