Thanks Santa (the neverending trials of the 400,000klm, 400kw, RB30, manual swapped Stagea)

[Duncan]

Well unfortunately after reviewing B-52 of the stagea manual and doing the following checks, it looks like it might be an ECU issue:

Pins 25, 32, 116 and 124 have good earths (interestingly 10 and 19 don't have pins in the plug although the diagram says they should be earths

Pins 80 and 109 have good battery voltage

ECCS relay pins 1 and 3 have good battery voltage, and if I earth pin 2 (normally the ECU earth trigger to turn ECCS on) the relay activates and I get battery voltage at pins 67 and 72 as well.

Also, when I plugged the old powerFC in it showed battery voltage on the hand controller, and started and ran the engine (poorly, since the AFM is no longer connected!)

So, based on all that I'm thinking it is an internal issue in the ECU, I've contacted Link to see what they say

[Dose Pipe Sutututu]

#nissanlife

The joys 

[MBS206]

So on the power input to the link, from the ECCS relay, it is showing only 9.5v?

But on the PFC, it gets full voltage (measured by the same multimeter?

 

If that is the case, it sounds like you've got a bit of an internal short starting to occur (hasn't gone to full short yeah) and likely you're seeing a decent current draw too with the Link on.

 

Is the Link under warranty?

I'll be intrigued to hear what they say, especially if not under warranty.

 

Then I want to see inside it if Link don't have an economical/efficient approach to repair it for you!

[Duncan]

Yeah not sure what the warranty was, but it will be years outside it.  I've shot Link a message, will see what happens, I'm told their support is good.

It is a plug in, so its a Link board in a factory case, very easy to access both sides of the circuit board by removing the top or bottom cover.

To be fair the the Link, although I've checked to the factory connections and wiring specs, as we learned with Neil's car in the early days not all ECUs source power the same way. He'd been running a factory ECU with no trouble for years, but when we plugged a PowerFC in it wouldn't start up, just kept cycling power on and off.

We worked out that the car was missing one of the 10a fuses "Electronic Parts", and to Neil's knowledge it had never been there. Turns out the ECU pulled its main power from that source not the same place the factory ECU did. 

Point being....there are multiple battery and ECCS power sources in the factory ECU, and multiple grounds as well....not telling from the outside exactly what the Link uses (and doesn't use)

[Dose Pipe Sutututu]

Time for millspec wiring, MoTec electronics package, Bosch Motorsport ABS, let's goooooooo!!!

 

Maybe as @MBS206 suggested, just swap out those stupid blue relays near the ECU plug.

 

[Stick180]

Just out of interest, did you check the "ENG CONT" fuses in the engine bay fuse block? I had a very similar issue to this with my Link, and those 2 10a fuses were blown, so ecu was only getting 9~v, whilst having 14v supplied to the rest of the vehicle. 

Likely not the problem, but just thought id make the suggestion after having a similar problem.

[Duncan]

49 minutes ago, Stick180 said:

Just out of interest, did you check the "ENG CONT" fuses in the engine bay fuse block? I had a very similar issue to this with my Link, and those 2 10a fuses were blown, so ecu was only getting 9~v, whilst having 14v supplied to the rest of the vehicle. 

Likely not the problem, but just thought id make the suggestion after having a similar problem.

Thanks for mentioning, especially when it is so similar.

I did check all driver's knee and engine bay fuses....but will do so again now you have mentioned  I think there is a relay there too so I'll sway that as well.

[Duncan]

11 hours ago, Dose Pipe Sutututu said:

Time for millspec wiring, MoTec electronics package, Bosch Motorsport ABS, let's goooooooo!!!

 

Maybe as @MBS206 suggested, just swap out those stupid blue relays near the ECU plug.

 

lol not on my budget!

Interesting about the relays too....instead of 2 blue ones as shown on the wiring diagram I have a single brown one which controls 2 circuits in one relay....I did switch it out too, and also tested it by earthing the signal and it was working fine

[MBS206]

Just to double confirm Duncan, the ~9V on that wire, you see that with a multimeter too, but when PFC is plugged in, your multi reads 12V?

 

I'm guessing a component in the link on its way, likely a capacitor.

 

I'm keen on Link response, and then internal photos if they say jump. With our powers combined, I'm sure we can get all the electrical smoke out

[Duncan]

Hey Matt, no I think I've misled you...I'm not sure that the ECCS power supply to ECU had 9.5v, just that the ECU reported 9.5v.  

Link got back to me pretty quick and suggested to check the IGN power supplies to the ECU

Pin 24 is the IGN key signal, which is working OK (ie battery volts with key on IGN)

Pin 31 is "IGN power supply" and sure enough that is giving 0v with IGN on

So, back to a car side problem, which is good because at least I can work it out here. On the down side I don't have a wiring diagram for Stagea so its the old fashioned trace and check task. @Stick180 I did double check those fuses are OK (I double checked all IGN fuses) and I also pulled and swapped the IGN relays at the driver's knee as a quick check with no change....but something is wrong there somewhere

[Dose Pipe Sutututu]

37 minutes ago, Duncan said:

Pin 31 is "IGN power supply" and sure enough that is giving 0v with IGN on

Check the wiring behind the headlight that connects back to the engine harness (assuming the stagea's layout is similar)

That plug should supply IGN power to the harness from what I remember.

[soviet_merlin]

2 hours ago, Duncan said:

On the down side I don't have a wiring diagram for Stagea so its the old fashioned trace and check task.

How much of a difference would it make having it? I have a paper copy of the S2 Stagea (1998) wiring diagrams. I could try and take some photos if there's a section you want. Not sure how well it would work with the 25 meter foldouts.

Table of contents:

[Stick180]

Looks like 31 and 24 are fed via the same IGN source, so its gotta be the fusible link, the relay or the fuse here:

[Duncan]

Hey David....I'll just trace this through, but if you ever find yourself at the officeworks A3 scanners with a few hours to kill the Stagea world would appreciate it

Josh I looked at that too but I think it is a "conceptual" not physical diagram. The ECU pinouts on the following pages describe them differently as I posted above and the different results support Dose's theory that it is a different source/routing....not that I understand why it follows a different route when there is no engine bay ignition switch relay so it must go back to the cabin near the key anyway

[MBS206]

@Duncan can you put the Link in, and measure all the power input voltages with a multimeter. Specifically looking for one that is low.

 

Then put the other ECU in that it runs on, and measure those voltages again with a multimeter?

 

If all of your voltages read normal on both ECUs, but the link is still reading low internally, your issue IS the LINK.

If the voltages drop low on the multimeter while the Link is plugged in, but not other ECU, then the issue COULD be wiring in the car, or it COULD be the ECU.

To rule out wiring, work out how with an ECU removed, you can trigger all the necessary relays, and then measure resistance from the pin that is reading low at the ECU, to the batteries positive power.

 

I have a sneaking suspicion your issue is the link, it's not reading the voltage properly, possibly a dry joint, or a Cap dieing, and because voltage is low, it's likely attempting to compensate on fuelling and the engine won't run.

[Duncan]

Hey Matt, Link pointed to the 2x IGN power sources from the car as a likely issue, and sure enough pin 31 in the loom does not have power when IGN is on (24 does).

So at the ECU, (and this is probably the case for R32 as well as C34) most of the ECU loom goes through the firewall behind the blower motor and there are 2 plugs (of 3 in the junction box) which go up and under the dash, the third plug heads under the carpet to places unknown (likely a body to dash loom joint)

So, I started to follow that problem through yesterday. Like Johnny (and R32) I assumed that power was supplied through the 2 connectors near the left headlight so I spent some time pulling the intake etc off and cleaning of 400,000klm of dirt and oil leaks and checking those pins, but there was nothing related to the engine parts or ignition fuses there (and no purple with white trace wire in either side of the connectors)

Given that the wire didn't seem to go via the engine bay, I then checked there is continuity from Pin 31 to the second connector to confirm no wiring issue in the ECU loom (it looked likely, given how much that has been hacked up over the years!). The pin marked with the purple dot is the other end of the wire to Pin 31

Then I check for IGN power in the dash loom side of that connector with the key on. Nothing. Given that loom goes up and underneath the top of the dash there is no tracing it without taking the dash out, so I went to the driver's side to see if I can find the other end of that (I'm expecting to get to big body junction boxes after I pull enough apart).

However, to get to those functions, I had to pull the covers off the drivers side, I'm pretty sure the problem is in this pic

Yep, factory remote start (bottom right), local immobiliser (middle) surrounded by 20 years of butchery.

Plan is to totally remove the remote start and immobiliser (I think I will lose remote central locking temporarily as a result) to remove all the suspect stuff given I have other more modern security in the car

It's gonna take a while, and it is both cold and uncomfortable out in the shed, not looking forward to it.

[GTSBoy]

Yuck. I wouldn't want to have to do the same thing in my car for similar reasons. It's possibly not as bad as that under my dash, but there is at least a local immobiliser/alarm, with internal siren, plus some of my own hurried botch jobs added on top, from....about 25 years ago.

[MBS206]

Glad you've tracked it to a cause!

You could just cheat, and jumper the power wire that works into the one that doesn't (just don't let it back feed).

And to solve the cold garage issue, come use my garage, I've been sweating balls in there!

[Duncan]

9 hours ago, GTSBoy said:

Yuck. I wouldn't want to have to do the same thing in my car for similar reasons. It's possibly not as bad as that under my dash, but there is at least a local immobiliser/alarm, with internal siren, plus some of my own hurried botch jobs added on top, from....about 25 years ago.

Yeah exactly how I ended in this mess, including my hurried botch jobs that I'm now paying for

3 hours ago, MBS206 said:

....You could just cheat, and jumper the power wire that works into the one that doesn't (just don't let it back feed).....

If I can't identify the proper source in another day's work that will be the go for sure....its is a very simple bodge.

Because.....

OK, so both the dealer fitter remote start and the locally fitted alarm are out.

In the end it was easier than it could have been because the remote start was a plug in loom to the key, and all the butchery for the local alarm was in that flying loom...big win!  I did have some stuff I just could not work out in the alarm like a pair of speaker wires tapped into something below the driver's seat (boot lock maybe?) and something running into a blue wire in the a pillar near the roof....in any case I'm sure they are not an issue so they are removed. I kept the extra central locking actuator in the driver's door for when future Duncan refits central locking.....but that did mean I had to remove all this swanky deadening from a page or 2 ago to check that's what the wires are for

So, now it looks like this....hard to tell but it is much better and I cleaned up the hurried bodgy jobs while I was there (still need to find a good ignition source and connect one other wire for a gauge once I've worked out where best to run it.

So, plugged it all back in, turned on the Link.....and no change, still got 9.5v at the ECU (I didn't check pin 31 for IGN power because it was late, and 4 degrees.)

What I did discover while in the footwell is that Nissan decided the Stagea needed 9 separate relays in there....

 

So....next is to have a good physical look for a purple and white wire while hanging upside down. If I can't find it I'm taking Matt's advice and running a new wire and forgetting this whole saga ever happened.

[MBS206]

@Duncan don't bet on the colour being the same.

In my R33 as wires would go through the big bulk connectors, they'd happily change the colours of them.

You're probably going to need to trace it fully manually.

Alternatively to my other bodgy solution. Find an ignition source off the key barrel. From memory there is two there, you want the one that stays on when you hit "start". Take that, run it to a new relay, put it on pin 86, from pin 85 run that to a switch (that you want to hide), then the other side of the switch, wire it constantly to ground.

Now run a new cable direct from the battery (put a fuse in it near the battery!!!) put it on pin 87.

From pin 30, run that to the wire at the ECU (completely disconnecting the old one.) at the same time, run this wire up to your new gauge that you want.

 

With the switch "on", the new wires you ran will follow the position of the key, coming on when you turn to "on". If you flick the switch off, the ECU never gets that power signal. Hence hiding that switch, as it's a new hidden kill switch.

 

Switch only needs to be rated to handle about 0.14A, as it's only carrying the coil power for the relay.

PS, another trick is I could sell you a GPS tracker my work builds, the GPS tracker becomes the hidden switch for you, just changing the setting needs 4G reception. Although, sitting beside my desk at work are the modules for direct to satellite too, so then you'd just need a clear sky, perfect for living in the wilderness