Power Fc - How It Saves It's State

[rtune]

From the power fc FAQ, this circuit diagram is the closest I have come to an answer

to my query:

http://paulr33.skylinesaustralia.com/docs/...eccs-wiring.jpg

So I understand that IGN on powers up the pfc ecu (or the stock ecu) and, START

makes the ECU light up the ECCS relay and the Coil relay: the ECCS relay

powers up the CAS sensor and the AFM (engine sensors) and the coil relay lights

up the coils.

ECU senses cam position etc etc & fires & car starts.

What I don't understand is what happens to trigger the power-fc to save state

and the sequence during shutdown..

I've seen several posts about in other forums particularly where either

the ECCS relay is broken or the wiring loom is wrong or the engine has been

swapped (wiring loom wrong) and the save problem is in the power-fc faq.

So.. ignition goes off and .. what? the ECU, still powering itself through ECCS,

writes all the changes to non-volatile memory, then does _it_ turn off the ECCS

relay itself by pulling pin 16 to ground? (which withdraws power to the engine

sensors and other pins on the ECU)? is the ECCS relay just a regular relay like

any other or is it more complicated inside?

If it works as I describe does simply supplying non switched 12v to pin 49/59/109

with an inline fuse, does that allow the power-fc to save its state (although since

this would leave power to the ecu always, perhaps it be a drag on the battery).

The reason for all this is I have a car alarm that is so knitted into the wiring that

it is able to pull ALL power from the ecu connector on ignition off.. I'm faced with

a choice - pull the dash and pull out the entire alarm, or solve the immediate

problem to get power-fc to save state..

[GreeceS13]

The pfc needs 1sec more 12V at pin49,59 when you cut the voltage at pin 45 (so when you cut ignition).

12V Ign at Pin 45

12V Permanent at pin 58

Pin 16 to the relay and suply the relay with battery voltage with a new wire from the battery with a fuse so you will be sure thaw this voltage you will not cut from alarm.

[paulr33]

once confirmed, please advise

will add to PFC FAQ

[rtune]

suply the relay with battery voltage with a new wire from the battery with a fuse so you will be sure thaw this voltage you will not cut from alarm.

so with the ecu unplugged you should be able to see 12v on ecu harness pin

16 and 58.. and if you ground 16 (which turns on the ECCS relay, listen for a click),

you should then see 12v on 49,59 and 109 as well ?

Is that a good test?

[GreeceS13]

Oh you will melt something or you melted!!!

Pin 45 12V Ign

Pin 58 12V Permanent

When your ignition is on (red lamps at dash), so when the ecu have 12V at pin 45.... the ecu gives a ground at PIN16!!!

This ground opens the ecu relay!! So the ecu relay sends 12V to the 49,59!

If you gave or if you will give 12V at pin16 you will melt this pin and you will not anymore ground exit. (if you did it, I will tell you what solution I found)!

Ecu relay..

1 and 3 needs one ground (ground from pin 16) and one 12V permanent.

3 and 5 at 3 12V permanent and at 5 a wire that goes at pin49,59.

To understand which pin is the 3,5,1,2 see under the relay... it has some small numbers near each pin. The scheme at the face of the relay (that writes NISSAN) isn't with the right way printed.

Just read what I said you to connect at the relay and look at the metal pins to find some very small letters nears the pins and you will see the numbers.

[rtune]

Oh you will melt something or you melted!!!

Pin 45 12V Ign

Pin 58 12V Permanent

When your ignition is on (red lamps at dash), so when the ecu have 12V at pin 45.... the ecu gives a ground at PIN16!!!

This ground opens the ecu relay!! So the ecu relay sends 12V to the 49,59!

If you gave or if you will give 12V at pin16 you will melt this pin and you will not anymore ground exit. (if you did it, I will tell you what solution I found)!

Ecu relay..

1 and 3 needs one ground (ground from pin 16) and one 12V permanent.

3 and 5 at 3 12V permanent and at 5 a wire that goes at pin49,59.

To understand which pin is the 3,5,1,2 see under the relay... it has some small numbers near each pin. The scheme at the face of the relay (that writes NISSAN) isn't with the right way printed.

Just read what I said you to connect at the relay and look at the metal pins to find some very small letters nears the pins and you will see the numbers.

thanks, no I didn't do anything! just hypothetical.

the only time I almost melted something was undoing the battery live terminal

with a spanner and despite being careful in the limited space it touched a bit of chassis

and the zaaap the spanner got warm instantly, luckily I yanked it before it stuck!

ok..

without an ecu connected, just looking at the connector, I was trying to imagine a way to test if the loom

is operating properly with key on, then key turning off. Just test with multi-meter .. I think from your explanation

I can see what is necessary..

with ecu connected it is hard to know what each pin (each wire) has ..

Edited November 24, 2008 by r34nur

[GreeceS13]

No you must do with ecu connected.

Just push a little the terminals of the multimeter in the wires.

Find an ecu pin out to know what you will do.

[predator]

You should be able to shove a probe in the end of each ECU pin (from behind, you can still access the other end of the pin) and earth the other probe of the multimeter to check for 12v across each pin as you turn on, or turn off the car, and ensure everything is operating as expected.

(edit: what he just said )

[Keeper]

To revive a dead post, where is the ECCS relay on a R32? and the 30A fuse paul has drawn, is that the one in the engine bay?

[Keeper]

ignore that, behind the kick panel on the pass side near the ECU I beleive, not going out to the garage again till the morning though

[rtune]

ignore that, behind the kick panel on the pass side near the ECU I beleive, not going out to the garage again till the morning though

it is wherever you can hear the click sound a few seconds after you turn off the car ..

[benl1981]

I know this is an old thread but can you actually hear this slight delay (on shutdown) in the ECCS relay enegizing - can someone confirm this on an R33 rb25det? I.e. so you should hear the engine shut down when you turn the key - then about a 1 sec pause before you hear the relay kick in?

Is the ECU programmed to delay 1second before triggering that relay, is that how it works?

Why does the stock computer require that delay? is it for writing fault codes? As I understand the PFC requires it for tune writing.

Thanks

[89CAL]

Yeah you should be able to hear the relay click off after a short delay.

I'm not 100% sure on the stock ECU, but it may just be to save Crank position and general state of the car when it turns off to help with startup

But I dont know for sure, havent had a stock ECU for a while now

[benl1981]

thanks for that.

Back up on some of the other threads it talks of a permanent 12v to pin 58.

My r33 has 12v to that when ign is on but as soon as you switch the ign off this voltage drops but fairly slowly. Drops to 4v then drops about .1v every few seconds. Maybe the alarm is connected in with this 12v feed?

I would think this is the reason my ecu shuts down earlier as it would need the constant 12v to allow the eccs to shutdown the computer.

Thinking of running a permanent 12v line from maybe the clock over to the ecu so that pin 58 does in fact have a constant 12v. Unless there would be a closer constant 12v feed than to the clock.

I don't want to wreck the harness though. Would I be best tracing pin 58 wire back slightly and splice this wire I run in at that point?

Does the above make sense to anyone. It is strange my pin 58 doesn't keep 12v ..

[jan25]

once confirmed, please advise

will add to PFC FAQ

This is a very old tread but we have the solution for years and fixed many PFC's with that issue.

If anyone has got that sort of problem please contact us on http://fc-hako.com/pfc/contact/

Will be fixed and tested in one day. If the issue is with engine harness we will advice you how

to test it before shipping the PFC to us.