Nissan Map Functionality

General Information
Below will be a list of potentially important maps utilized in the 350z, as well as Nissan's/Infiniti's produced around the same time. A lot of maps that we think we understand, will end up being flipped on their head after a new discovery is made. So this list will be constantly updated as new information/advice is found.

This page is nowhere near complete and will need many more updates before being able to be used as an official resource.

1D Values
Accelerator Pedal Full Close Position Learning Initial Value- Exactly what it says. Datalog APS Voltage at idle when the vehicle is fully warmed up to get the value, then just plop it into this table in mV's and boom! It'll make it so at least THAT part of idle relearn will stay constant.

Throttle Full Close Learning Initial mV- Same as above but for the TPS Voltage.

EEPROM Reading/Writing Trial Number of Times- Just two interesting single value maps. Both have a value of 3. Not sure what reading and writing trial stuff is but they have maps haha

Consult2 CUID- a 20x1 table with three values at the beginning 25 27 128 0 0 0.... Not sure what this map's function is, but I'm guessing it would be treated like the others. I'm wondering if we could maybe alter consult functionality through this?

Ignition Timing Main Constant- Single value in g. Really have no clue what this even means, but I'm presuming it's just referring to a constant in one of the ignition timing equations. What does it represent? No clue.

All Ignition Timing Retard Limiters- There are multiple ignition timing retard limiters. But in testing, the limit still stays at -7 degrees for whatever reason. So disassembly will be needed to figure out which ones are called for and when. I'd highly recommend Ghidra as it makes understanding the code MUCH easier of a task. Ignition Timing During Torque Control- I presume this is just the set ignition timing during gear changes. Either the set or the base timing, that is. But more timing will result in less torque cut and less timing will result in more torque cut.

Torque Limiter (Vehicle Speed R/L)- Alex from Uprev stated that it deals with fuel cut at a certain torque point per gear and that it typically only applies to automatic equipped vehicles. I'm thinking this is the fuel cut limiter for mVSPCT speed limiter. Because the regular speed limiter is very gentle, while mVSPCT legitimately cuts fuel. So if engine torque value exceeds the limit, it cuts fuel. It should be based on the Engine Torque map. So it'll be gear dependent for sure due to QH0 %. Which is exactly what I found to be the case in testing. If I was one gear above the lowest possible gear, it wouldn't trigger the limiter. So it'll typically only trigger if you're in the lowest gear for whatever speed you're going.

2D Map Tuning
AFR Conversion Table- A direct mV to AFR table. I personally haven't tested this table out, but you could potentially get more accurate readings by adjusting the axis and values to 0-2V instead of 0-4V. Technically if you could get a wideband to hook up to factory harness and be compatible with the stock wideband controller, I believe you could adjust these values to accommodate aftermarket widebands. But even Uprev hasn't tried that yet.

Fuel Cut Tables- Fuel Cut Prohibition Speed is most likely for when fuel cut is absolutely prohibited. Uprev calls it "Fuel Cut Prohibited Table." But the notorious Bosch/JECS, should be simple to figure out if anyone cares to try it out. Theoretically, JECS should be the only one active since JECS/Hitachi made the SH7058 ECU's for the Z I think? But it could be vehicle/ECU dependent.

GOV/GOV3/GOVL Tables- I'm not entirely sure on these three maps functionalities. They're base timing during decel or idle, maybe even both?

Initial Retard Quantity 1->4- These are pretty self explanatory. But why there are so many tables for the same set of values, I dunno. How do these maps work with trimming and such? No clue haha But they're the initial retard values the ECU will follow in whatever circumstances they're triggered.

PTD On/Off Switchover Step Value Table +Low Speed- This will directly affect ETC performance that's based on torque. It's apart of the function "Target Drive Force ON/OFF switching (main calculation section)" I'm not entirely sure what the axis is either. It's a fixed axis and it could be Nm, N, or something entirely different. No clue how to tune this table either, but it's definitely something that would be useful once we figure out how to utilize it.

TDM Table and Base Torque Table- No clue. Apart of function "Composition of Requirements on Torque Correction (ignition: for MPI)"

Up Shift Limiter (TENG2)- This will only apply for automatic equipped vehicles. This is scaled in Nm, while the axis indicates the gear being shifted to. So 1- Idle/nothing 2-Shifting from 1st to 2nd gear, 3- shifting from 2nd to 3rd gear, 4- shifting from 3rd to 4th gear, 5- shifting from 4th to 5th gear. It's a torque (throttle) cut map. So the higher the values, the more throttle cut occurs. I'm not entirely sure what would be best, but I'm experimenting with it. Theoretically, the less power loss during shifting, the better. But transmission reliability come into play as well. Why is there more torque cut shifting from 2nd to 3rd than from 1st to 2nd? Don't ask me, but Nissan did that for a reason I suppose.

At Time of Acceleration, AC Cut Judgement VAPO Table- This will directly control when the AC is cut during WOT. Scaling is in presumably TVO degrees. So if you want the AC to cut sooner, you can lower the values. Or if you want to have AC not be cut during WOT, raise them past ~84 degrees.

Full Increase Judgement VAPO Table- Called "Throttle Peg Table" by Uprev. This appears to be the TVO in degrees for determining WOT. SO if TVO exceeds the set values, then the ECU will determine it as WOT. What benefits are there to be gained from this? I don't know to be honest. But if Uprev has it defined, it's important. What's weird is the A2L has it apart of the "Target Equivalent Ratio" functions. I presume those are AFR related, but maybe not? Or maybe WOT will affect fueling different than non-WOT.

Target AFR
'''This map is what AFR the ECU will try to achieve in each cell. You'll want to keep the table smooth in order to hit your targets in each cell and not have your AFR be stuck halfway between cells.'''

Not confirmed, but it's possible that setting any of the values to 1 lambda will have the vehicle operate in closed loop mode.

All Timing Maps- The knock window can be added or removed by adding or removing 128 to any cell. So add 128 to whatever cell you want to be included in the knock window or remove 128 from a cell that you don't want to be inside the knock window.

Engine Torque Map- ONLY used in automatic equipped vehicles. Directly affects line pressure for shifting. I've been getting incredible results from this table alone. Shifting faster than my friends RE5 that has a shift kit haha But the axis situation is unfortunate. The axis' are fixed so it gets a filling efficiency %, RPM reading, and scales off of that. So the current axis' from the A2L are a rough estimate. Uprev has this table set up with the cam timing axis' just to try making it easier to understand. But it's hard to tell which one is right. Stock filling up % will never breach 100%. So that makes me think that since this table is scaled off that reading, then wouldn't it be a 0-16 starting at 0% and ending at 100%? Meaning this table should probably follow the cam timing's axis? Just a thought for now. But it would be nice to figure that out because as of right now, 1/3 of the map is useless as you don't have a clue if it's even hitting those cells or not.

QH0 Maps- A literal torque demand map. This directly affects throttle. Raise the values for more throttle opening, lower for less throttle opening. At least in theory. Think of it as more of a throttle open/close request trimming table. The base TVO is based on 2D maps entirely. But this QH0 map acts as a trimming map for those values. This table is more useful for anything but WOT, as throttle will typically always be 100% at WOT. Using an online excel document available on a 370z forum I think, you can very easily set up a calibrated QH0 map. If you raise the values using this tool, I'd recommend going back in and dropped the values in the lower left half of the map as failing to do so causes delayed downshifts in automatics and potentially rev hang in manuals. ''DO NOT ADJUST THIS TABLE IF YOUR THROTTLE TAPERS NEAR REDLINE. THAT IS NORMAL. All Z's have something called throttle cut. It is set about 150rpm before fuel cut. This is intentionally put there so that you'll hit the limiter more gently. This is also what causes automatic Z's to bog instead of bounce off redline. (For V3 TCM's, at least.) So if your throttle tapers you can either move throttle cut closer to rev limiter (at least 100rpm before fuel cut) or remove it entirely.''

Target Drive Force Maps (mMTFDD and such)- These need more testing. But view D as 1 and Ds as 2. So D Range maps are linked (probably need to be set equal or else it'll result in limp mode) and Ds Range maps are linked. So while the Qh0 map is torque request, this is, I guess the target drive force. So it's maybe acting as a base map as well that gets altered by torque requests and such. I have no clue what the difference between the D and Ds one is. Maybe Drive and Manual mode/Sport mode (for vehicles equipped with either)? But it'll result in more or less throttle opening, most likely.

Catalyst Temperature (Before/After Activated Judgement) Maps- These 3D maps are presumed to be EGT maps. I'm not sure if it's acting as a translation from O2 voltage, or if it's referenced by the rear O2's to determine catalyst condition. Further investigation would need to be be done. Apart of A2L Function "FTP Catalyst Diagnosis".

mMWTOY and mMYTOW- Before I thought maybe they were throttle 8x8. But after speaking to Alex from Uprev, we were able to determine that they're both EVAP related.

TTEPTD Torque Compensation Map- X Axis is scaled in gear ratio (variable, not set) Uprev calls it "Throttle Enhance" Apart of "Calculation of Engine Torque" function as well. From Alex, "The values in the table are lambda or AFR. It's for the powertrain torque demand, so it checks this value last after checking the ETC map 1-5 to make a powertrain decision on how much torque to send across. Personally, I render it based upon the A2L which calls for "compensation percentage" but it can be thought of as an air to fuel ratio compensation percentage, so divide by 100 to get lambda." I feel like further testing is definitely required. A Z1 Tuned Z had these values set to 200% surprisingly. But datalogs showing what exactly it's doing will be needed. Uprev has this inside of their map switching section as well. So it's important enough to be a switchable map!

APOFS Shaft Conversion 1 and 2- Base throttle open-degree tables for APOFS shaft conversion. Accelerator Opening Degree Fail Safe is what I think it stands for. I believe that this is the 1:1 relation throttle map that the ECU will run in the event of some sort of failure. Uprev has ETC disable available that sets the throttle to a 1:1 telation and this would line right up. The issue is whether this acts purely as a failsafe or maybe these also act as the base throttle maps before torque management trims and alters it? https://patents.justia.com/patent/6276333 I'll eventually dig through that and it should tell us just about everything we need to know about throttle control. But it's heavily dependent on torque control.