How To Get Rid Of Sluggish Coldstart/warmup And Bad Fuel Economy On Your Nistuned Rb20Det/z32/gtr Ecu.

[Manuel Kasko]

So for my short trips in cold canberra weather to and from work (about 20min stop start traffic)

Could this be the cause of such poor fuel economy such as 200-250km per tank ?

Sucks that this is only discovered a few months before I sell the car haha

[GTSBoy]

Yup. Economy would be improved by allowing it to stand and warm up for 3 minutes before driving. Also possibly by closing off half the radiator air flow (given cold Carntberra air)

[Manuel Kasko]

Oh well I'll pass this onto the person who ends up buying the car I guess. Adaptronic in the 34 won't have these issues

Thanks for the info rolls

[Rolls]

So for my short trips in cold canberra weather to and from work (about 20min stop start traffic)

Could this be the cause of such poor fuel economy such as 200-250km per tank ?

Sucks that this is only discovered a few months before I sell the car haha

It would make your economy worse but not that much worse, I was getting 15-16L/100km driving 10 minutes to work and back each day, I think I get more like 14-15 now, I actually get better economy if I do a few runs through the hills as the speed is so much higher.

200-250k to a tank (~20L/100km??) sounds like a fuel leak or boost leak or a bad misfire at cruise. I'm happy to make this change to anyones nistune ECU if they are here in Adelaide, only takes 20 minutes.

Edited December 15, 2013 by Rolls

[Manuel Kasko]

Been driving off boost and granny shifting

Still bad economy.

Could be a fuel leak but who knows.

Not spending any more money on this car

[R_34]

I don't think the RB20 is very fuel efficient at low revs given its design.

I'm getting 10L/100 in extra urban driving with some pulls and the EUDM S13 final drive ratio (3.962).

[Lithium]

The code explaining this equation is as follows:

ldaa   X145D
ldx   #TIMING_ADVANCE
jsr   L809F
psha
ldaa   X1544
ldx   #$AFTER_START_TIMING_ADVANCE   
jsr   L809F
tab
pula
sba

Once you have burnt these changes to your ECU you can enjoy the car driving like it is hot on cold start and warm start! I gotta say it makes driving the car so much better, no sluggishness or jerkyness on startup. If you do a lot of short trips this will improve your fuel economy massively.

Anyway hope this makes some peoples cars nicer to drive!

Nice find, and good on you for putting together the post to share it I've never used a Nistune, and not sure that I will but it helps to know about this as a possible thing I could encounter if I do

In other news, reading that first post gave me a hell of a nostelgic moment haha... this is the first time I have seen assembly code which looked like it could belong on an 8bit Commodore or Atari computer (Motorola style assembly language) a discussion I'd be reading for interests sake in maybe nearly 30 years!! And the last time I did would have been in a computer magazine/newsletter that people wrote into with their questions and answers, so you'd potentially have to wait weeks before you had answers The last time I think I've seen assembly code come up in an online conversation was probably about 15 years ago (around the time I stopped doing that kind of thing for the fun of it) and I don't think I ever expected to see the stuff again, much less on a forum about Skylines! Way to go, made my day haha

[Rolls]

Thank matt from nistune, he was the one who knows the code well enough to find that snippet and explain it, mine was just a translation of what he said.

My job involves lots of old PLCs and writing ASM sometimes so that stuff is second nature to me, there is an ECU website which is where nistune evolved from which you might enjoy. Thousands of real programming sites with ASM galore on them if it is something that interests you though! Generally people avoid it like the plague unless reverse engineering something as languages these days are so much easier to write with their high level of abstraction.

Edited December 15, 2013 by Rolls

[GTSBoy]

languages these days are so much easier to write with their high level of abstraction.

Unless you want your code to be efficient.

The guy who did the sound programming for Crazy Comets and Mega Apocalypse for the C64 was given 4kB of memory and managed to pull out 5 different voices of sound (from a 2 channel sound chip) in 1983 or thereabouts. All done raw in ASM. These days that couldn't be done without at least 4GB of RAM and a full SDK.

[Rolls]

Unless you want your code to be efficient.

The guy who did the sound programming for Crazy Comets and Mega Apocalypse for the C64 was given 4kB of memory and managed to pull out 5 different voices of sound (from a 2 channel sound chip) in 1983 or thereabouts. All done raw in ASM. These days that couldn't be done without at least 4GB of RAM and a full SDK.

Memory is cheap and so is processing, you can get a PIC32 for $4 these days with enough flash memory to hold a C# stack and program in .NET

Was an argument many moons ago but not these days, if you want efficiency you can always use C++ and inline asm where appropriate and keep the rest of your code managed and high level, no need to suffer all day long writing just asm.

[Lithium]

My job involves lots of old PLCs and writing ASM sometimes so that stuff is second nature to me, there is an ECU website which is where nistune evolved from which you might enjoy. Thousands of real programming sites with ASM galore on them if it is something that interests you though! Generally people avoid it like the plague unless reverse engineering something as languages these days are so much easier to write with their high level of abstraction.

True - I'd had the conversation recently with a couple of geek mates about whether Assembly is likely to be used much, if not at all recently... partly for the reasons you provided below. I really am too lazy and don't have the motivation to get into that kind of coding these days, I don't think I've been in a situation where the novelty or necessity of it has really arisen.

Memory is cheap and so is processing, you can get a PIC32 for $4 these days with enough flash memory to hold a C# stack and program in .NET

Was an argument many moons ago but not these days, if you want efficiency you can always use C++ and inline asm where appropriate and keep the rest of your code managed and high level, no need to suffer all day long writing just asm.

The guy who did the sound programming for Crazy Comets and Mega Apocalypse for the C64 was given 4kB of memory and managed to pull out 5 different voices of sound (from a 2 channel sound chip) in 1983 or thereabouts. All done raw in ASM. These days that couldn't be done without at least 4GB of RAM and a full SDK.

Haha the last piece of assembly code I wrote was a 2.5kb self contained game as a result of a geeky dick swinging session on FidoNet, I still have it floating around but I am getting less and less confident I will be able to run it on anything soon due to it being MS-DOS based and using direct hardware access etc. I was fully inspired by that kind of thing, I learnt how to write machine code using a VIC-20 which didn't have enough memory to hold an assembler AND do anything useful with it (~5kb of user memory). We used to try and squeeze as much as we could out of seriously under-power machines, and it was amazing what people could get C64s/Amigas/early PCs to do - real time. I think the me over 20+ years ago would be both amazed and (/ or?) horrified at the code I do now hahahaha.

[Rolls]

Do you get to write anything interesting these days instead?

[Lithium]

I reckon so - work for NZ's Meteorological Service as a software engineer, developing software which is used to create weather related shows using meteorological data... like this:

Channel 7 in Oz use our software, amongst a bunch of other stations around the world - definitely my cup of tea, I always was into science and also programming (especially graphics related) so pretty sweet to get paid doing stuff I could do for fun

Going OT no doubt, but it's interesting seeing what goes on behind the scenes with folks that frequent these forums and talk about almost completely unrelated stuff What do you do exactly that means you need to tweak bits and bytes from a low level?

[niZmO_Man]

FK yeah engineering! I used to love doing these kind of stuff (e.g. basic PIC/ASM programming at uni), then I got a job in I.T. and it was all over lol.

[Rolls]

FK yeah engineering! I used to love doing these kind of stuff (e.g. basic PIC/ASM programming at uni), then I got a job in I.T. and it was all over lol.

Go get a job in engineering then! engineering ftw, I love my job, it is more of a hobby but I get paid really well as a bonus! makes turning up each day pretty easy

[GTSBoy]

Half your luck. If either of my kids ever express an interest in engineering I'll be trying to dissuade them as hard as I can. Dealing with moronic clients, moronic management, moronic sales staff, moronic junior engineers.......just too much hassle.

[Rolls]

Half your luck. If either of my kids ever express an interest in engineering I'll be trying to dissuade them as hard as I can. Dealing with moronic clients, moronic management, moronic sales staff, moronic junior engineers.......just too much hassle.

That is just a problem with the business/company not the industry, should come work with us, we are in adelaide!

[Lithium]

That is just a problem with the business/company not the industry, should come work with us, we are in adelaide!

Yep imho that kind of thing happens all over - when you have various people of various backgrounds, experience levels etc then you easily end up with a turbulent flow and there is always going to be messy highs and lows. Where I am working things seem pretty laminar (relatively speaking), basically a whole pile of people who are level, intelligent and feel like they are working towards a relatively common goal - but I guess a certain amount of that comes down to company culture and managing to hire the right people to keep it consistent, if they are able to.

So it looks like we're on topic

[niZmO_Man]

Go get a job in engineering then! engineering ftw, I love my job, it is more of a hobby but I get paid really well as a bonus! makes turning up each day pretty easy

Wish I can. I dropped out of uni and am dumb now. I'm Unix-ing to pay the bills.

[Rolls]

Wish I can. I dropped out of uni and am dumb now. I'm Unix-ing to pay the bills.

never too late to go back part time, I spent 8 years doing my degree, 4 years full time, got a job as an engineer then spent 4 years doing 1 topic a semester to finally get my piece of paper.