Nismotronic SA ECU tuning and settings

[nick_d_240sx]

I'm working on street tuning my SR20DET with a Nismotronic SA ECU and was wondering if there are any 'tuners' that might have some insight into certain settings, including but not limited to, fuel, ignition, trims, boost control, limiters, accel/decel and idle. After I feel good about how the engine is behaving I may seek out a professional opinion. I have read a lot of the users manual/help on the Nismotronic but there's gotta be a few tips and maybe some typical settings that can improve drivability that I'm unaware of or don't understand completely. I'm aware that w/o some 'knock ears' and EGT there may be some difficulty to tuning but I'm not looking for maximum power and currently it does run good.

Some general things I'd like to learn more about are:

How timing affects spool and where timing can be added to improve it.

Good timing and Bad timing in respect to low rpm in vacuum and midrange/upper rpm in boost.

Map table column(inhg/psi). More vacuum columns and less boost columns?

ACCEL/DECEL settings and effects.

Limiters.

Trims.

Other settings that can improve drivability or cool tricks/tips that you have setup and tested.

Sharing TCD files (tune files)

I'm currently running MAP(speed density) based tune and am currently working on dialing in the fuel map and making some adjustments to the ACCEL settings. I'm having a few issues where it'll go lean on light throttle input under low load conditions as well as an issue where it will idle fine cold at ~14AFR but once warmed up only likes ~12AFR. I haven't ruled out a bad 02 sensor, but it seems to be working fine. I have not checked compression on the stock unknown mileage SR20.

I'd like to stay on topic of the Nismotronic and not discuss other ECUs but if there are similar technical aspects feel free to bring them up.

1990 S13 stock SR20DET w/ GTX2863R at 14psi, 740cc injectors, rewired walbro 255, front mount, 3" exhaust, AEM WB02.
https://i.imgur.com/6l3wmfrl.jpg

Current Fuel Map
https://i.imgur.com/chIJ0ycl.jpg

Current Timing Map
https://i.imgur.com/3iW3qssl.jpg

Link to Current Thread on 240sxforums (https://www.240sxforums.com/forums/new-member-introductions/183866-got-240sx-sr20det-engine-500-a.html)

Link to current TCD file (tune data file) (https://drive.google.com/open?id=1kyh9G0kbUYv055yqn2zQEXLy3_KRyGxl)

Link to folder if you would like to upload a TCD file. (https://drive.google.com/open?id=1Xx_QR7Iq3Onoalfmwwge9jkaWJNwW4LZ)

[nick_d_240sx]

**This didn't fix the light throttle lean issue, it was the fuel map.**

In an effort to get rid of a lean AFR issue during light to medium throttle input I decided to dig into the Async accel parameters. After some additional review of the logs and help files it seems as though the dMap accel need quite an increase over what the base map has. This could have to do with enabling dMAP Fuel Trims and the dMAP values not being a factory/stock setting.

Async Parameters - Left at factory settings
https://i.imgur.com/zmviCz2.jpg

Async Factor Tables - Bumped up the MAP Load factors in the Vacuum area.
https://i.imgur.com/dMF09HU.jpg

Accel Parameters - Enabled dMap fuel trim, Lowered the dMap deadband to register lighter throttle inputs, lowered the decay factor to prolong the accel trim effects, No change to update rate. **Edit: raised dMap decay up to 3%**
https://i.imgur.com/RjZySbS.jpg

dTPS Accel - added some % to the dTPS RPM Factor Table to enable accel trim a little higher into the RPM range (Probably no effect since I'm running dMap fuel trims)
https://i.imgur.com/0EiU1oW.jpg

dTPS Load Factors - I don't think this changed, but if it did I just matched the dTPS MAF values.
https://i.imgur.com/Bwz2Rao.jpg

dMap Accel - Heavily increased the dMAP Load Factor Table in the midrange vacuum areas. I noticed in the help file these values were quite different than the base map and in comparison to the dTPS Load Factors these values are quite a bit lower, which is where I was experiencing lean AFRs (16-17 and sluggish accel) upon throttle input. Also Increased the dMap RPM factor table to cover more rpms where I was noticing lean AFRs on light/med throttle input.
https://i.imgur.com/tZLzQHM.jpg

I'm not sure if I even need to mess with the dTPS values since I have enabled the dMAP Fuel Trim, but by increasing the dMap Accel it has really cleaned up the lean issue I was experiencing during light/med throttle input. Not perfect but a huge improvement.

I have not modified decel or overrun fuel cut.

Still noticing rich values, 12.5 AFR, at idle after some runs and warmed up, but it idles great though. Idles good ~14AFR when ECT cold/cool but at ~1100 rpm. Stock plugs NGK BKR6E on brand new factory coils.

[5280VertDET]

Thank you! This is very helpful.

[Ichi-Go]

Thanks for posting this and including the screen captures. I find the Nismotronic super interesting. Would love to go flexfuel one day and run it. I'm going to bookmark this thread.

[Solo70510]

Subscribed as I am also new to Nismotronic. Getting close to firing up my build. This thread would be really helpful.

[JKTUNING]

Thanks for this post - I can help add to it when I get some time to make a more detailed post.

I will say for starters though - your fuel table should resemble your engine torque curve, even though is isn't called a VE table, it is directly related to engine efficiency.

With that being said, the engine won't idle and part throttle at the same table value for the same column. Don't be surprised if you need to increase your ECT fuel trim table (for lower ECT) and then lower your fuel table once the vehicle is warmed up to maintain a more stable idle AFR across the engine warmup range.

A couple other helpful tips can be found in some videos in the wiki section here.

http://www.j-k-tuning.com/Wiki/doku.php

[nick_d_240sx]

Thanks everybody. I hope we can get some good information, what works, what doesn't, details and information about settings and their effects. Basically, how to get your shit running good (enough) w/o blowing it up.

I think I sort of know what I'm doing, but I am learning as I go and am by no means a 'pro-tuner'. If anyone, including John, has more insight or knowledge, correct me if I am wrong.

On a hardware related note, I would suggest getting a USB extension cord. It helps having a little longer cable for routing and if the plug on the ECU USB cord were to get damaged you'd have to crack open the ECU to replace it or send it in for repair.

One other thing, do not unplug the USB cable from your laptop while the ECU is 'connected'. It will crash the software every time. Always pick the 'disconnect emulator' button first.
https://i.imgur.com/RryUPCem.jpg

[speedingmofa]

Good thread! I'll be following this one closely.

I'll be tuning my nismotronic too for the first time. Just like you, i've been reading loads and loads. Have a visual knock monitor and aural stethoscope with a copper tube attached to block as it's my first time. I'll be driving around with it on stock tune to get used to the engine sounds before changing of block.

As for your cold idle being 1100, there is a setting that correlates idle rpm to engine temp. 1000-1200 is pretty normal for cold idle even in stock form.
I'd also say, a cold start up should give you a richer mixture, ie afr 12-13 and lean out as it warms up to 14-15. Why yours is the opposite does strike me as odd.. could you have been messing with the idle fuel tabs when the engine wasn't completely warmed up? Or the settings to richen the mixture based on ect?

[supersayianjim]

Bump, im also new to the nismotronic scene and its a process

[nick_d_240sx]

I've been trying to get back to this thread with some updates and trying to fix a few issues, mainly the light load high AFRs and why it idles at 12AFR when warm but misses and sputters at anything above 13AFR. A little frustrating and makes me feel like I have no idea WTF I'm doing, but I'm confident I can figure it out, eventually.

I did get a chance to go out and drive it hard for a bit and everything seemed fine and it ripped pretty good at 16psi. **7/10/19 Edit: still messing with this and set it back to 1000mbar** However I did need to make some changes to the EBC setup. When setting up the EBC you need to convert millbar to psi for the activation load. I had it set to activate at 0 psi of pressure (14.5psi or 1000mbar) and it wasn't building boost as fast as I thought it should have so I ended up setting it to 1800mbar (26psi atmosphere or 12psi pressure) and it seemed to come on better. I will update with some screen shots and more information soon.

My window regulator broke and I'm trying to find a new one, so the car is down at the moment. **fixed w/ brand new regulator $220.**

[nick_d_240sx]

I was going to heavily edit my post above, because it seems I may have went a little to far with the dMapAccel stuff, but I want to leave it as a reference to additional changes that I have been making or will make. Maybe as a 'what not to do'. I was getting really rich bumps when touching the throttle and some pops from the exhaust shifting at low rpm.

Since editing and raising up the dMapAccel wasn't solving my lean midrange, I increased the fuel map in the lower vacuum areas. -10inhg to 2psi and this made quite the difference however it is not perfect. If you compare it to the map above you can see the difference. For those wondering why my positive pressure map is mostly all the same value, I use the boost fuel trim to increase IPW based on boost.
https://i.imgur.com/VScJ3Yd.jpg

Using the TCD compare under the tools pull down, I compared my map with the canned SR20DET_RT_MANUAL.tcd.
Link to Nismotronic wiki for TCD Compare (http://www.j-k-tuning.com/Wiki/doku.php?id=compare)
Be sure to save your map when making changes or comparing, because I did have it crash/fatal error when trying to compare the fuel map and the software just closes.

My Base IPW ECT settings. I raised this based on John's comment above.
https://i.imgur.com/ByWCulg.jpg

Difference between maps
https://i.imgur.com/2S5GYhg.jpg

Map Load Factor Table.
https://i.imgur.com/cbegcAc.jpg

Difference between maps
https://i.imgur.com/42DSXL6.jpg

ECT corrections
https://i.imgur.com/f4gnRsS.jpg

Difference between maps
https://i.imgur.com/lC2rrcR.jpg

When I went from stock 370cc injectors to 740's I updated the injector size but left the 370 as the base. This allowed me to start the car and start tuning.
https://i.imgur.com/HxnCXQI.jpg

Also when making these changes I'm trying to keep transitions smooth by using the, super handy, graphing feature.

I still get the ~12afr idle and I've tried leaning it out and when it goes above ~13.5 is starts missing and popping.
Fuel injector base pressure to low? Stock plugs fouled? **Edit: ordered BKR7EIX plugs** WB reading wrong? I need to look into it, but I'm not convinced it's the tune because it used to idle just fine around ~14afr.

If anyone would like to see the current map and a recent log it is posted up in the link on the first post.

Edit: Is anyone using an aftermarket knock sensor and can you give me any details about why you like it, how you installed it, and how your using it? I keep noticing some weird spikes from the stock sensor around 4700rpm and I'm not sure if it's a knock or just unreliable readings from the stock sensor. I'll do some research as well, just thought I'd throw it out there..

Edit 1-16-20: Car is down for a few upgrades. Thinking the rich idle is from not having the crankcase vent ran to vacuum which will be fixed. More to come in March when I get back at it.

[nick_d_240sx]

Ok. I'm looking for any help on why my engine is not idling consistently.

The Problem: From cold start up it will idle rough at 15-17 AFR at 17.5in/hg until it warms up, not to any specific temp, but at one point, like a light switch, the idle will smooth out except that it idles at 12.5 AFR and vacuum jumps to 20.6in/hg. And to make things more confusing once the electric fans kick on it idles perfect at 13.5-14.5 AFR, once they kick off goes back to 12.5 AFR.

I had a couple ideas but no real conclusion.

Blocked or sticking AAC/IACV valve, however adjusting the limits on the ECU does seem to change the idle, but does not help improve the situation. I did mess with the screw on the IACV a little bit and that changes the idle fairly drastically. Once it was all warmed up I adjusted it to Idle right around 975. I had no reason to adjust the throttle stop screw or anything like that.

Something with the tune or some parameter causing it to do this, but I cannot find anything. I checked the injector battery/voltage offset. Nismotronic has a preset for Nismo 740cc, that's what I'm using.

I've checked the base fuel pressure. 43psi with no vaccuum.

Could it be something mechanical? or electrical? or in the ECU? Or?

I did not touch the throttle at all during this log. Strictly turned the key and let it idle until the fans came on.

Idle at startup
https://i.imgur.com/4dQ798Il.jpg

Idle warming up
https://i.imgur.com/yj88cSjl.jpg

Idle snaps into rich smooth idle mode
https://i.imgur.com/8v9qonzl.jpg

Idle with fans on
https://i.imgur.com/yi0Nm3Rl.jpg

Driving around, low load cruising and boosting all seem to be just fine.

Link to the TCL Log file (https://drive.google.com/open?id=1Y1Zf3xdNeNmziiUWreYl3S3Q7vtOoYto)

Link to the TCD Tune Data File (https://drive.google.com/open?id=17kCFumZN5dfUdQtKDFv6VK2tgtumIvJO)

Any Help or Suggestions is Appreciated!

https://i.imgur.com/wAqkn3al.jpg

I will soon be installing a Bluetooth dongle and doing some messing around with TunerView which I'm pretty stoked about!

**Edit 4-23-20**
Tried poking around at vacuum lines and anything connected to the TB, intake, as it idled and no changes, but it was the same exact thing and the same exact temperature. 172ish, which it seems, is right about when the thermostat cracks open. Will do more poking around..

**Edit 2**
Pulled the intake to inspect the TB and didn't see anything except the bottom of the IM looked a little wet. Think I'm going to check if an injector is stuck/sticking and going to pull the TB and clean. I was able to blip the throttle and get the vac up to 20.3 FWIW. Might end up pulling the intake manifold and clean it all up too and inspect the valves.

**Edit 3**
Removed Intake manifolds and cleaned and inspected. IACV tested out fine, but after putting it all back together it's the same shit. I'm not sure if I should adjust the throttle plate/stop screw, or just replace the IACV...?

**Edit 4 - 5-13-20**
Tested IACV and it seems to be working 100%.
Maybe it's a voltage issue. When my fans kick on the voltage drops to about 13.4 volts and the AFR's go up to 14-14.3, idling fine, the AAC goes up to about 49% Vac down to 19.1. Once the fans kicked off volts go up to about 13.6, AFRs to 12.9 and Vac up to 20.3 and the AAC drops to 43%.
https://i.imgur.com/Y3Hipaeh.jpg https://i.imgur.com/e3dRaBlh.jpg https://i.imgur.com/2NRL4awh.jpg https://i.imgur.com/wcPg5Rjh.jpg

[OnTheChip]

The only thing that changes when the AFR drops is manifold pressure. Nothing in the tune that would effect AFR is changing. All parameters are nice and steady. Something is allowing extra air into the intake manifold until ECT hits 172 degrees. At that point, the "leak" stops, manifold pressure drops, and AFR drops.