ER34 AT ECU and HKS SLD pins

[GoHashiriya]

Hi all,

I need to get this HKS SLD attached to my stock ECU because I've now got the German autobahn and faster European circuits to contend with. 

The car is a manual 2dr ER34 with an AT ECU and I've realised the AT ECU has two pins for speed sensor signals:

Pin 29: Vehicle speed sensor signal (Vehicle speed sensor 2)

Pin *58: Output shaft rotation sensor signal (Vehicle speed sensor 1) - *RB25DET A/T model only

Before I go butchering this harness, is anyone sure of which pin is the correct one for signal adjustment?

The attached document from HKS indicates pin 29 but I found this situation mentioned in the following thread on a different forum (R34 GTT Auto Trans Speed Cut Problem | Zerotohundred) mentioning pin 58 needing to be altered by member zephuros, albeit it seems to be for an RSM-GP and the info appears to be old. 

R34_All_Workshop_Manual-pages-2.pdf R34_All_Workshop_Manual-pages-3.pdf R34_All_Workshop_Manual-pages-1.pdf HKS SLD Vehicle Pin out P59-P70 ER34-pages.pdf

[joshuaho96]

Any chance you can get a Nistune board installed instead and set the speed limit to whatever your tires can handle?

[GoHashiriya]

3 hours ago, joshuaho96 said:

Any chance you can get a Nistune board installed instead and set the speed limit to whatever your tires can handle?

It’s a high priority but I can’t get a Nistune in before my next Nurburgring trip. 180 is pretty easy to hit on the back straight of the GP course. I should have got the Nistune installed in Japan - my friend offered to solder the board - but I had the same problem of just not wanting any downtime for the car. My guess is this winter when I rebuild the rear subframe  (which is what I said back in 2022) 

[GoHashiriya]

I say this and there’s a Nistune r34 GTT MT ECU for sale on eBay.de but I need to figure out compatibility between the AT harness and MT ECU - TCS considered. I figure this HKS SLD is a quick bandaid anyhow. 

[Duncan]

I don't know the answer, but my uneducated guess is this will not work (or, not as you want it to).

I would wire the SLD into VSS1, I bet that is what the limiter uses

However, I also bet the ECU compares VSS1 and VSS2 and throws and error if they are different.

Best suggestion I can make is wire it into VSS1 and see how you go, I guess the error will only appear above 180 when then SLD is active. If it appears at lower speeds put a switch into the SLD earth (or power supply) and only turn it on when you need to go over 180.

[GTSBoy]

OK, so. Look very closely at this.

Here is a snip of the ECU diagram.

Note that the VSS (Vehicle Speed Signal) input to the ECU is sent from the speedo head. The speed sensor on the gearbox (whether auto or manual) is connected to the speedo, and the speedo converts that AC voltage signal to a 0-5V DC PWM signal that the ECU reads.

Pin 58 is NOT used by the ECU. It is used by the TCU. And unlike Duncan's thought on the matter, I would think that the only comparison done (by the TCU) would between trans output shaft speed and engine rpm. This so that the TCU can know whether the lockup converter is doing its thing, the clutches are managing shifts appropriately, etc etc.

I would be willing to bet that the only speed signal you need to intercept with any speed cut defender, regardless of auto or manual transmission, would be the VSS into pin 29. That is the only speed signal available on a manual.

And here is the rub. Your car is a manual. So why are we even having this conversation. There is NO speed signal input on pin 58 on your car right now and it runs just fine. That should tell you how important that pin is for your manual ECU.

[GoHashiriya]

11 hours ago, Duncan said:

I don't know the answer, but my uneducated guess is this will not work (or, not as you want it to).

I would wire the SLD into VSS1, I bet that is what the limiter uses

However, I also bet the ECU compares VSS1 and VSS2 and throws and error if they are different.

Best suggestion I can make is wire it into VSS1 and see how you go, I guess the error will only appear above 180 when then SLD is active. If it appears at lower speeds put a switch into the SLD earth (or power supply) and only turn it on when you need to go over 180.

Thank you Duncan, and I will say, before reading GTSBoy’s response, this was more or less my logic. 

9 hours ago, GTSBoy said:

OK, so. Look very closely at this.

Here is a snip of the ECU diagram.

Note that the VSS (Vehicle Speed Signal) input to the ECU is sent from the speedo head. The speed sensor on the gearbox (whether auto or manual) is connected to the speedo, and the speedo converts that AC voltage signal to a 0-5V DC PWM signal that the ECU reads.

Pin 58 is NOT used by the ECU. It is used by the TCU. And unlike Duncan's thought on the matter, I would think that the only comparison done (by the TCU) would between trans output shaft speed and engine rpm. This so that the TCU can know whether the lockup converter is doing its thing, the clutches are managing shifts appropriately, etc etc.

I would be willing to bet that the only speed signal you need to intercept with any speed cut defender, regardless of auto or manual transmission, would be the VSS into pin 29. That is the only speed signal available on a manual.

And here is the rub. Your car is a manual. So why are we even having this conversation. There is NO speed signal input on pin 58 on your car right now and it runs just fine. That should tell you how important that pin is for your manual ECU.

I can’t argue with that. The part I couldn’t get past was thinking that the speed sensor in the 30A was replacing whatever was in the AT transmission before, and therefore completing the prior circuit.
 

The other thing that I failed to mention was that, across all HKS documents, despite mentioning compatibility with AT R34s, there is no mention of a different pin. These Japanese instructions appear to predate early man, so there’s always room for error. 
 

I’m speaking with the seller of this R34 GTT ECU with Nistune at the moment. It’s pretty cheap and eliminates the possibility of me soldering my fingers to the ECU when installing the board myself. I am yet to confirm whether the base ECU is from an MT or AT car, so the question is:

When using an MT ECU in an AT car, and then losing the TCU part, are there any other implications?
 

Another thing I’m not sure of is whether I can pass local regs with a TCS warning. Of course, swapping between ECUs is a fairly simple task.

[GTSBoy]

30 minutes ago, GoHashiriya said:

When using an MT ECU in an AT car, and then losing the TCU part, are there any other implications?

There is no impact. Granted, mine is in an R32, so there are a couple of other things going on, but.... my auto ECU came with the auto engine. Bolted it up to the manual gearbag and suddenly the TCU is just spare parts along for the ride. The ECU doesn't (really) care.

Nistune is the fixer of all wrongs. I have no ABS CU or traction control. That would be a recipe for fault codes and permalit check engine light. But....just go into the diagnostics pages and turn them off. Presto, ECU no longer cares that it can't talk to those CUs.

If you're worried about the TCS light being lit on the dashboard for some rason (that I am not catching right now), then.... remove the globe. No-one needs the TCS anyway. That is what throttle control is for. I certainly don't have it - haven't missed it in 12-13 years or so. Never wanted it.

[GoHashiriya]

11 minutes ago, GTSBoy said:

There is no impact. Granted, mine is in an R32, so there are a couple of other things going on, but.... my auto ECU came with the auto engine. Bolted it up to the manual gearbag and suddenly the TCU is just spare parts along for the ride. The ECU doesn't (really) care.

Nistune is the fixer of all wrongs. I have no ABS CU or traction control. That would be a recipe for fault codes and permalit check engine light. But....just go into the diagnostics pages and turn them off. Presto, ECU no longer cares that it can't talk to those CUs.

If you're worried about the TCS light being lit on the dashboard for some rason (that I am not catching right now), then.... remove the globe. No-one needs the TCS anyway. That is what throttle control is for. I certainly don't have it - haven't missed it in 12-13 years or so. Never wanted it.

That’s the one. Yeah, the seller has confirmed the base ECU is from a manual car. 
 

To be honest, I’m only worried about the TCS light being illuminated due to registration here in NL - unsure on rules. Back in Japan, we weren’t allowed to have any permalit error-related lights (or so my shaken guy said). 
 

Looks like this Nistune is the way to go then, appreciate it GTSBoy, and the others that chimed in. 
 

[joshuaho96]

6 hours ago, GoHashiriya said:

That’s the one. Yeah, the seller has confirmed the base ECU is from a manual car. 
 

To be honest, I’m only worried about the TCS light being illuminated due to registration here in NL - unsure on rules. Back in Japan, we weren’t allowed to have any permalit error-related lights (or so my shaken guy said). 
 

Looks like this Nistune is the way to go then, appreciate it GTSBoy, and the others that chimed in. 
 

If the TCS light is controlled by the ECU just patch it with Nistune to turn it off. I personally hate wiring in stuff like the SLD because it requires cutting into the factory harness when all you really need to do is patch a byte or two in the ROM.

Just to wire in my dash cam and some other future expansion I've bought a sealed bus bar so I don't have to run multiple fuse taps for accessories that want +12V, ignition signal, and ground. Clean wiring goes such a long way to preventing annoyances when debugging all this crap.

[GoHashiriya]

TBH, I’ve hit a bit of a dead end with this. 
 

The Nistune’d ECU for sale is mapped for a big turbo, which is completely different to my stock motor. My friend (Nistune user) tells me I’ll need to get a new base map on it (no shit), which could - depending on the age of the Nistune board - mean sending it off to Nistune themselves to get it done. Price for this ECU is €355. Then I’ve still gotta buy a license. 

Sending my ECU for installation at Nistune costs about €400 (~AUD 700) including a license. So, plus shipping will be about another €200/AUD 350 (EMS), total around €600. I imagine downtime around a month. This seems to be the smartest option. Or have a crack at the soldering myself - I’m not that cack-handed. 

At this point I’m at Power FC money - does it work with an AT harness.. I can’t remember. Yes, PFC is not as good as the Nistune, but this option requires zero downtime. 

Then I’m thinking f**k it, this is a pain in the ass, I just wanna go rag it on the track; so SLD and then Nistune over winter… I figure I can do some reconstructive surgery on the harness with the some nice little crimps and heat shrink and it’ll look as good as Michael Jackson in his final form.
 

 

[GTSBoy]

1 hour ago, GoHashiriya said:

I’ll need to get a new base map on it (no shit), which could - depending on the age of the Nistune board - mean sending it off to Nistune themselves to get it done. Price for this ECU is €355. Then I’ve still gotta buy a license. 

Just buy a software license and put the stock maps into the (tuned for a worked engine) Nistune. It is not difficult.

I cannot imagine owning Nistune without owning Nistune Software. Just....how could anyone contemplate it?

[joshuaho96]

8 hours ago, GoHashiriya said:

TBH, I’ve hit a bit of a dead end with this. 
 

The Nistune’d ECU for sale is mapped for a big turbo, which is completely different to my stock motor. My friend (Nistune user) tells me I’ll need to get a new base map on it (no shit), which could - depending on the age of the Nistune board - mean sending it off to Nistune themselves to get it done. Price for this ECU is €355. Then I’ve still gotta buy a license. 

Sending my ECU for installation at Nistune costs about €400 (~AUD 700) including a license. So, plus shipping will be about another €200/AUD 350 (EMS), total around €600. I imagine downtime around a month. This seems to be the smartest option. Or have a crack at the soldering myself - I’m not that cack-handed. 

At this point I’m at Power FC money - does it work with an AT harness.. I can’t remember. Yes, PFC is not as good as the Nistune, but this option requires zero downtime. 

Then I’m thinking f**k it, this is a pain in the ass, I just wanna go rag it on the track; so SLD and then Nistune over winter… I figure I can do some reconstructive surgery on the harness with the some nice little crimps and heat shrink and it’ll look as good as Michael Jackson in his final form.
 

 

If you don't have a friend with a Nistune license just buy one. Then you can flash whatever ROM dump you want. The Nistune ROM pack has the actual stock maps for literally every ER34 ECU as far as I can tell, both AT and MT.

[GoHashiriya]

7 hours ago, GTSBoy said:

Just buy a software license and put the stock maps into the (tuned for a worked engine) Nistune. It is not difficult.

I cannot imagine owning Nistune without owning Nistune Software. Just....how could anyone contemplate it?

 

56 minutes ago, joshuaho96 said:

If you don't have a friend with a Nistune license just buy one. Then you can flash whatever ROM dump you want. The Nistune ROM pack has the actual stock maps for literally every ER34 ECU as far as I can tell, both AT and MT.

Sorry, I should be clear, buying the software license is not a problem. The problem is my other source of information has told me that depending on the Nistune feature pack version, I may not be able to flash a base map myself and *may* require a feature pack update at Nistune. Does this sound accurate?

[joshuaho96]

20 minutes ago, GoHashiriya said:

 

Sorry, I should be clear, buying the software license is not a problem. The problem is my other source of information has told me that depending on the Nistune feature pack version, I may not be able to flash a base map myself and *may* require a feature pack update at Nistune. Does this sound accurate?

Contact Matt at Nistune. If the wiring on the ECU has been messed with in order to get certain outputs like launch control, flex fuel, and boost control you might need to change it back to make it work normally again. 

[UWISSH!]

Sorry if I missed it somewhere, but why are you not just getting an aftermarket ecu and be done?

[GoHashiriya]

50 minutes ago, UWISSH! said:

Sorry if I missed it somewhere, but why are you not just getting an aftermarket ecu and be done?

Basically, I want to drive at the track ASAP without the 180kph limiter. Nistune offers an element of future-proofing and means I won't have to butcher the harness (comparatively to installing the HKS SLD).

Power FC is an option but everyone has told me not to buy this.

Link/Haltech is just not worth it for me, cost wise.

Issue with Nistune is I'm too spastic to solder the board myself. So that leaves buying the aforementioned pre-installed used one from a seller on eBay, then reflashing it with the stock map and killing the limiter.

 

 

Edited April 30 by GoHashiriya
grammar

[GTSBoy]

If the Nistuned ECU is set up to be an RB25DET ECU, then you can put any maps into it you like. You need a programmer to put the actual ECU firmware onto it (the first time, or to change it for another different engine application), not to change maps.

As said above - all the Nistune base maps are freely available in the ROM pack.

[GoHashiriya]

Speaking with Matt now, seems to be a more cost effective solution to just buy new from Matt - approx 300 EUR - then my local electronics store just told me EUR 100 to solder it in and I guess I'm good to go 600kph.

[joshuaho96]

6 hours ago, GoHashiriya said:

Speaking with Matt now, seems to be a more cost effective solution to just buy new from Matt - approx 300 EUR - then my local electronics store just told me EUR 100 to solder it in and I guess I'm good to go 600kph.

Yeah, if he has one lying around you could send yours in on an exchange basis.