33 Gtst Won't Start With Power Fc, Will With Standard Ecu

[Duncan]

I've got a bit of a strange problem.

33 gtst (series2) starts and runs fine with a standard ECU

Put a PowerFC in it, and it does not start. I've tried 2 different PowerFCs with the same result (could just be unlucky but seems very unlikely).

Other than not starting, the other obvious issue was the fuel pump relay clicking like crazy.

Finally, the PFC only shows 8.4v although the battery voltage is a healthy 12. I get 12v everywhere except at the ECU.

Any ideas?

[GTRsean]

I remember reading on PM33's sticky on this problem. (think that's his name)

You might need to check your fuses to make sure none are blown or it won't power up properly.

But it will run on the stock ecu like that...

[sleptema]

Unless the PFC has been flashed to a stock ECU tune, I believe it wouldn't allow your car to start either. It'll try overfuel, timing will be out slightly, etc.

Am I right?

[Ben C34]

No.

[Ben C34]

It won't over fuel, why would it? If anything it would under fuel as you go to bigger injectors typically.

And timing is pretty much not changed in the low rpm and idle when tuned.

Edited April 19, 2014 by superben

[sleptema]

It won't over fuel, why would it? If anything it would under fuel as you go to bigger injectors typically.

And timing is pretty much not changed in the low rpm and idle when tuned.

Yeah, sorry I meant underfuel.

[Aggroman]

I've got a bit of a strange problem.

33 gtst (series2) starts and runs fine with a standard ECU

Put a PowerFC in it, and it does not start. I've tried 2 different PowerFCs with the same result (could just be unlucky but seems very unlikely).

Other than not starting, the other obvious issue was the fuel pump relay clicking like crazy.

Finally, the PFC only shows 8.4v although the battery voltage is a healthy 12. I get 12v everywhere except at the ECU.

Any ideas?

AFM??? standard ECU would go into limp mode whereas PFC will almost start but no dice.

I know I had this problem with my PFC a year or so back and it turned out to be one shorted wire somwhere along the loom on top of the engine but started just fine with the standard ECU.

you need one of those trick things that finds a short along a wire though

[Ben C34]

Fair enough.

I'm sure in this case Duncan has that part sorted.

Edit: above in reply to sleptema. Really should have pushed quote, oh the regret....

Edited April 19, 2014 by superben

[Duncan]

Yeah thanks guys, I am sure the immediate issue that prevents starting is insufficient power to the fuel pump relay = no fuel pressure = no bang. And that appears to be caused by very low voltage at the PFC (8.4v not 12+). The map may not be usable but I have a datalogit and can reset it if necessary.

I know I had this problem with my PFC a year or so back and it turned out to be one shorted wire somwhere along the loom on top of the engine but started just fine with the standard ECU.

you need one of those trick things that finds a short along a wire though

Do you know what the short was? I suspect it is something nasty like that....so any hints will help.

Sean, would love any more hints or a link (i'll have a poke around).

I did see some threads talking about a fuse or relay which doesn't prevent the std computer running, but does prevent a PFC working properly. I didn't find specifics though, so I would love more info if someone has some

[dvd50l]

I can recall something about some relays mounted near the ecu that can cause a no start with a power fc or something like that (was a while ago lol), have you checked the power fc FAQ in the tutorials section?

[djvoodoo]

Would it have anything to do with NATS ?

[R31 POWER]

http://www.paulr33.com/powerfc-faq/powerfc-faq.htm#68

[KiwiRS4T]

http://www.paulr33.com/powerfc-faq/powerfc-faq.htm#68

Almost there - FAQ #71

[Duncan]

Thanks guys. I did see the generic info in Paul's guide (which is excellent BTW)

However I'm looking for more specific info or experience if possible. Here is the pic from Paul's doc:

There is also troubleshooting info on EN-311 of the R33 Engine Manual (translated by JPNZ)

There should be constant power on pin 58. The ECU then earths pin 16 to ECCS relay pin 2 (and ECCS relay pin 1 should get power from the same 30A fuse as ECU pin 16). When that happens the ECCS relay then has power (from the same source as ECCS pin 1 and ECU pin 16) which turns on the ECU via pins 49 and 59 and 109. And I understand all that complexity is so that the ECU can turn itself off after the ignition turns off; this allows both the standard ECU and PowerFC to write back changes to ROM before shutting down (and this is why when I pull the kill switch to stop the car that the PowerFC doesn't save changes)

So; that all sounds good; except I can't find power at ECU pin 58, ECCS pin 1, 3 or 5 at any time. This does not match the manual.

Engine manual EN-312 shows there should be continuity between ECCS 3 and ECU 49/59. I have no continuity there, but instead have continuity from pin 5 to ECU 49/59. So, it does not match the manual there either.

So given all that; I was hoping someone might have direct experience; perhaps the Series 2 R33 wiring is a little different to the manual. Does anyone know the location of the "30A" fuse shown on the diagram above? EN-312 calls it F/L-6 which I would expect to find in the boot next to the battery (BTW I have checked all fusible links and fuses in the boot and driver's side dash, all are fine).

So given all that; if there is no other specific info I will wire up a fused 12v source to ECU 58 and ECCS 1 and ECCS 3 (not 5 due to the continuity difference) and see if that brings it all to life. I'm away for a week so am hoping for some tips before I have to start cutting

[Duncan]

well...that didn't lead to a load of responses. I guess out come the side cutters

[Dose Pipe Sutututu]

Would it have anything to do with NATS ?

No

....

Duncan, have you tried replacing all the relays?

A low voltage could mean the relaying supplying current/power to the ECU is faulty.

If not, there's the old - direct power to ECU trick (fused of course, this is what a mate of mine did also).

[Duncan]

yeah I did swap the ECCS relay for the HICAS relay from the boot with no change. But I don't think it's that because pin 1 of the relay never gets 12v so it could never work.

I just don't understand how it can be a wiring issue when the ECU loom is all standard....but that is none the less what it seems

[Dose Pipe Sutututu]

Wow that's very interesting, however not the first case of it either.

Maybe ping Trent at Chequered he might have an idea since he's installed and tuned thousands of PowerFCs where as I've done two LOL

[Don Dada]

Seems like the bottom line is the missing constant 12volt to pin 58.

Do you get a 12v at pin 58 when you plug in the oem ecu?.....because I cant see the oem ecu working without a constant 12v there anyway.

And dont worry about pin 3&5 on the relays as well, they could be either way around once one goes to pin 49,59and 109, and the other goes to a 12v once the relay is energized.

Likewise with pin 1&2, once one goes to pin 16 and the other to a 12v

Have you tried placing the missing10A fuse as per Pauls faq?

Otherwise, you are good to go with with hard wiring it as you suggested.

[Duncan]

Thanks everyone for the help/suggestions. Just a quick update, I've confirmed the PFC works OK in another car so I'm going to go to work on the loom.

I was hoping to get specifics about the mythical missing fuse, but in the absence of that I put 3 engine/ignition related fuses in which were missing, but no luck.