stupid_fast

Useful info, thanks. I agree I don't think the ECU is actually dealing with a KPA scale. For tuning purposes, it helps put the tables into perspective and compare to other timing maps and megasquirt logs. I got a little overexcited that the TP scale was matching up to kpa almost perfectly. Good info on the BMW stuff, I'll look into it. Maybe someone figured those out and that knowledge will help decipher the code here. The main reason I referenced the Audi ECM is because it uses the same hitachi chipset, not because its a similar EFI system. I believe those are a primitive speed density system from what I could tell ... I think you're referencing a different mechanical injection system which were somewhat common in the 80s. I believe some Volvos also used the system you're describing. The AFM as I can tell hasn't maxed out, as my fueling with flat targets from 4400 to 6000 are pretty consistent and don't lean out much in that range. In that range the afr change is maybe 0.4 from 4400 to 6000, not what I'd expect if the AFM was at its maximum but I've been proven wrong before. I need to get something like the Moates SuperLogger or an Arduino with custom code to communicate with Tunerpro so that I can get some proper logs of what the AFM input is actually doing. My current logging system is primitive at best, using the Innovate AFR output and tracing rom address hits. When I get my car on a dyno we should have a better idea of how much flow I'm actually pulling through it. The fact the calculated TP drops steadily after 4000rpm seems to indicate the ECU is off somehow, but everything in my setup is pretty much as good as you can get it and there's just not enough of these systems around to compare my results. I haven't spent enough time cruising above 4000rpm to check if the AFR targets are accurate at lower load. Z31 ECCS employed a VQ table for the MAF, I believe they may have implemented that due to the fueling error on the s130. There's some lingering unused data on one of my 1982 ECM's that seems to imply they were trying to implement a similar feature. I no longer use spring tension for tuning. I set the spring tension so the AFR targets are dead on from 10kpa to 120kpa, up to 4000rpm. I briefly documented this on the last post on page 1. This method works for best closed loop operation and overall driveability in cruise ranges. Correcting the top end & boost areas by adjusting the AFR target table I get repeatable results, I can slap a factory sealed AFM on and will get the same AFRs. The later E36's and some other cars also have WOT maps, its pretty common to have multiple fueling maps. As you say, it won't work for turbo unless its some kind of an enrichment table based off of manifold pressure ... Now that would be interesting.

After chatting with Gollum about tuning and pouring over his megasquirt logs and comparing our timing charts, I got familiar with KPA. I noticed something very interesting, the TP scale in the ECCS acts a lot like a KPA scale. With some logging I compared it to the vacuum gauge, with an in/hg to KPA conversion table handy it looks that my hunch is confirmed. The TP scale does convert to KPA! So, here's some factory tables with the converted KPA scale for reference. Please note, above 3600rpm and above around 120kpa the AFM is very inaccurate. The KPA scale is accurate in same ranges that the AFR targets are accurate. Also note in later ECCS models this is a 'theoretical pulse width' scale, and not KPA. But its interesting that it does follow KPA in stock configuration.

An update, which will be expanded upon with more technical posts later on when I'm able to dig into it. With a rebuilt rack after the failure at my last Thunderhill west event 9/23/2018 I rebuilt my power steering with all new seals. The pump was also rebuilt including a very expensive OE reservoir cap to fix all my leaks. On returning to Thunderhill west a couple weeks ago on 3/17 I show up to the track, turn my car around in the pits to unload my track gear and there's a puddle of ATF on the ground. The rack blew out before I even got it on track! The driver side boot was full of ATF, same side that failed last time. Unfortunately with the smog test due and some other personal things getting in the way I have no time to fix until later next month, I'll be recording here and hopefully finding a mistake in the rack rebuild that caused the seals to blow out again. I still ran on track, just removed the PS belt & drained the rack. In car footage will be on youtube once I get around to splicing all the good bits together. Anyway, its been a long time since I washed my car and I finally did it today. Also haven't taken many pictures of the car in its current state. Goes to show what a bit of cleaning can do even to a beat up car!

Here's what I've got on the AFR target table. I cleaned it up a lot and got it running in the 11.5:1 range from 2800~6000rpm. Additionally I've increased the closed loop range and leaned up the part throttle operation up to 0 boost significantly, this gave a lot more responsiveness and torque in the part throttle areas. The part throttle areas, especially the 5th gear cruising for climbing hills is still a work in progress. As I understand it so far, based on my testing and documentation on later ECCS systems the ECU calculates a theoretical pulse width for a lambda of 1.0, or 14.7:1 AFR based on current RPM and mass air flow. After this TP value is calculated, the TP is used to look up an enrichment percentage from the AFR target table based on a TP (load) and RPM scale. the AFR target value is a multiplier for the calculated TP before the injectors are actuated. Several other enrichment tables are also referenced, I'll go into the details later when I have solid information on them. The stock AFM becomes very inaccurate past 3500rpm or so, but does have consistent readings. This is possible to correct by bumping the AFR values rich, I have 9.62 AFR targets to get a 11.5 measured AFR above 5000rpm. Its much more time consuming to tune than something like megasquirt, but definitely has good results. I've come up with a calibration procedure for the AFM by disabling closed loop and setting the fuel table to static fuel targets. I use the address tracing feature of the rom emulator with TunerPro to see which cells are being accessed, logged next to the wideband output. Any value other than hex 00 (14.7:1 AFR target) results in open loop operation, disabling o2 input. This makes it possible to adjust the AFM spring tension and idle screw and get the AFR targets almost dead on on low to medium throttle input up to 3000rpm. Once the AFM is giving accurate AFRs in open loop below 3000rpm this gives a solid baseline for adjusting the fuel table. The IAT enrichment table can also throw off the afr calibration, I haven't figured out exactly how that scale works yet. note; AFM sweep should never be touched from factory, only spring tension and idle screw adjustments. Its very hard to get the sweep back to the factory value if its been changed, and it generally only has negative effects. Here's the fuel target table I use for the AFM calibration.

Thanks Gollum! Its good to have some appreciation for my work. The car still needs a lot of sorting for grip configuration, the tires are still too small. Lots of tuning left to do. Last time on Thunderhill west with 205 tires all around I had a best lap of 1:33.844, that was with the old motor and stock ECCS running in the 10:1 AFR range spitting 6" flames out the exhaust. I really want to do more grip days with the car, but most of my friends drift so I've been doing that most of the time. @Datmarshall on instagram, I haven't updated it in a long time. I used to post something up after each event. My youtube page 'Initial Bonk' has some in-car content from various track days. I try to post a video for every event I go to. https://www.youtube.com/channel/UC_Prm-4M1uRIb1Ulg_umy5Q @swiftsurfer I stopped posting here when I lost interest in continuing public documentation on my build. Continuing from December 2015, the crank case was full of water but the head gasket and all the seals were fine when I disassembled the block. I ended up getting some spare heads and blocks and assembling a completely new drivetrain, although pretty much the same setup as before. Everything from the radiator to the stub axles have been changed at this point, including new rear wheels(not pictured). The whole car, every nut and bolt forward of the seats, was rebuilt in 2016 and only running again in late January 2017. I proceeded to Bash to the Future V and wrecked a door unfortunately, so this was the end of the livery. Since then I've attended a few more events, but generally the car has been sitting more than driving. I replaced my 510 with a geo metro some time in 2015, so I drive that most of the time. There's been some more development on the car, such as issues with too much amperage draw with the taurus fan causing belt slip whenever it turned on. I switched to a quest alternator with some better belts, and a pair of spal fans. Also started a write-up on mounting issues with the quest alternator, but haven't finished it. A lot of smaller changes were made, such as adding a gauge panel for the radio slot. The power steering rack blew out on the last trip drifting at Thunderhill West, so I finally rebuilt the whole power steering system. I also finally figured out that 205mm tires are tiny, and completely insufficient for the chassis weight. I've been drifting on 225's, but they're still too small for any serious track performance. I have only about 5000 miles on it since the fresh drivetrain. The miles are racking up again since I started developing tuning methods for the stock ECCS, details can be found on my thread over in the EMS section. Here's some pictures on various tracks from last year. This is the last you'll see of those center line reps, I decided I like grip more than fitment. Please note I do not own any of these photos, they're re-posts and credits are due to the photographers who come out and shoot these events without pay. On another topic, I've also joined a Lemons team with a BMW E36. I will be driving the upcoming March 9/10 event at Sonoma Raceway. Edit, Decided this was a good place to post my Nissan Quest 125amp alternator swap. (around 5/2018) The taurus fan was pulling too many amps, I had belt slippage issues when it would kick on and low voltage. I used a file to flatten the top of the alternator casing to fit the v-band pulley. Lapped the spacer down to get the pulley as close to the alternator face as possible. It doesn't wobble even though I did this by hand. The vbelt was still significantly misaligned with the water pump & crank pulley, I had to cut the tab a bit to bring it into alignment again using a file. not ideal but kept it flat enough to align properly. Couldn't get the camera to focus properly on this one. Added a spacer in the mount to compensate for the lost material. The result was good. Checked alignment to the water pump pulley and the crank pulley. The setup now requires a shorter belt & adjustment rod. I used a generic domestic alternator adjustment rod that comes with 3/8" rod ends and added bushings to drop down to 5/16". Belt part number is an A34. A43 belt works for power steering. I used gates hi power belts, they're great. they actually tighten up when they wear instead of loosening up. However this was only a band-aid to the real issue, which was that terrible taurus fan. I swapped over to dual spal 12" fans, they flow about the same and pull a lot less current. I also remounted the oil cooler right up against the radiator so the fans actually pull through it now, although oil temps aren't an issue I want to keep it that way. Finally centered and leveled my seat bracket properly Also I learned small tires suck, and started running a 25" tall rear tire. Changed the diff to keep the gearing the same. The M30 open diff is a very interesting design compared to the old R200's. No matter, its metal and that means it can be welded. As I've started plate welding diffs, I added some small plates inbetween the gears as filler material. The carrier will split in half before this breaks. Here's an S13 diff I did not long ago, you can see its much stronger than the first one I did on my car. I did the PRW2 swap. Going to add some accel 8.8 plug wires later as well, they're on the shelf somewhere. Details are important. Added a gauge panel to fill the empty hole in the center console, as well as house my chippernut shift light. After adding an oil temp gauge worrying that my oil temps were too high, I actually came across the opposite issue. My oil temps were actually too low cruising on the highway, so I added an oil thermostat. The ZX has a strange notch sticking into the rear arches, I don't like tires rubbing so I cut it out. Don't mind the booger welds... I ground them back after Summary, almost everything I've done on the car since the 2016 rebuild has been fixing details, correcting small issues or replacing parts of the setup that don't work properly.

Following Gollum's suggestion, I've added the disassembled microcode to github. https://github.com/eccs-reengineering/280ZX-Turbo-ECCS/tree/master/DASMx Disassembled Code Its Motorola 6800 assembly code. The instruction set can be found here: http://www.8bit-era.cz/6800.html#ASL-A-ACC The 1984 Quatro MAC-02 Hitachi-designed ECU is based on a similar chipset with the 6802 CPU & HD46506 ADU. I've found some disassembled code from it, it maybe useful. I've attached it to this post. No idea who disassembled the code or if there's any more information about it online. quatro_1984.txt

Hello, I'm looking for some spare AFMs to test from a 1982/1983 280ZX turbo model. Preferably an unopened original unit that came from a running car. Hoping someone still has one laying around. JECS # A31-630 840 NISSAN 22680-P9010

I think Zhoob answered your question sufficiently, It looks like you had the right idea in your post. The cold thermostat bypass was more for people who hop straight in their car and run it up on the highway at high revs cold, that is the only condition where you need additional coolant bypass. The L series block already has a built-in bypass for the coolant which is sufficient for most street applications. If you still want to put the correct valve in there, I believe the part number is 27188-Q0105, around $36. Personally I deleted the one off my setup, one less thing to go wrong on the track. 27195-E4400 is the single outlet fitting for the back of the head. @timz, yes the L28ET is only rated for 180hp from the factory, however 148 seems a bit low even for a stocker. I thought I saw some old dyno sheets that were closer to 160whp. The AFRs at 5000rpm seem a bit rich, but the fuel curve is right on match with the factory fueling map. Possible the AFM spring is worn out. @OP what ignition timing are you running? Stock EFI should be 20 degrees with idle switch plugged in. (ask me how I know) Although this probably doesn't matter much if you're going megasquirt anyway.

Unrelated to your fueling, but something I noticed with your setup that wasn't addressed, The original T-fitting you replaced on the ZXT heater hoses is a bypass reverse thermostat for warm up! You cannot simply replace it with a T-fitting, you've created a coolant bypass. Hot water is now coming out of the head, and going straight back into the water pump. Cap or put the single outlet fitting on the back of the head. That way the only time coolant will flow back there is when the heater core valve is open. I made the same mistake and my car would never stay cool on the track until I found that out. Also generally a good idea to check all hoses, clamps, and fittings.

Hey Nathan! Its been a while! Last time I met you I had just gotten the turbo motor running. This system is definitely very far from ideal and not much cheaper to setup than megasquirt or Z31 with Nistune. After a few tuning sessions I've been able to get the AFR's closer to what I want to see, but the analog AFM as a load measure is terrible compared to a modern system with a MAP sensor. Increased fuel cut to 6700 and fuel scales to 6500, seems to keep pulling strong up there. Megasquirt as you say seems like its stagnated, probably because its 'good enough' for most applications. I've been leaning towards trying Speeduino for my next step up, or even DIYEFI with the freescale board. Mainly did this modification because I was wondering why nobody else had done it before. Once I started learning a little bit about 8-bit ROM chips it quickly spiraled into what you see in this thread. It ended up being fairly simple to do, just required lots of research, studying datasheets, interpreting hex data and testing changes. Not sure if I need any more ECU's, but I'll keep it in mind! I could use a factory calibrated AFM or two to check how far off my settings are. On another note my o2 correction isn't working like it used to anymore... might've toasted the o2 sensor or broke something. Update; I've setup a public google drive with the related files to this project. The ROM Address spreadsheet is probably the most interesting file. It only includes a partial translation for the map portion of the ecu ROM, I have made no progress in disassembling the microcode. Any addresses highlighted in green I have tested and verified as correct, all other comments are speculation and unverified. https://drive.google.com/open?id=1mRNbCs317YusVA-wutB3DW7AYV1MVt2l Update; I found the fuel table calculation, it is in fact target AFR similar to later Z31 ECCS. Still a long way off to interpreting the microcode to a point of finding the pulse width calculations. 14.7/((X + 256)/256) hex 0x00 = closed loop flag. These are targets, doesn't necessarily mean the ecu will hit these mixtures at every range properly especially with a worn out flapper AFM. I have calibrated my AFM in the low end and it hits AFR targets as expected up to about 3200RPM, its inaccurate past this point.

Found the RPM scales, RPM fuel cut, and maybe the idle/cold start timing map. I'll post up the excel sheet when I'm done with it. RPM scales are 16x1 DWORD 12.5*X 7B80 to 7B9F - Unknown 800 1200 1600 2000 2400 2800 3200 3600 4000 4200 4400 4600 4800 5200 6000 6400 7BA0 to 7BBF - Fuel Scale 400 500 800 1200 1600 2000 2400 2800 3200 3600 4000 4400 4800 5200 5600 6000 7BC0 to 7BDF - Timing Scale 800 1000 1200 1400 1600 1800 2000 2200 2400 2800 3200 3600 4000 4800 5600 6400 7BE0 to 7BFF - Unknown 800 1000 1200 1400 1600 2000 2400 2800 3200 3600 4000 4400 4800 5200 5600 6000 Fuel cut DWORD 0x7F50 Decimal: 520 12.5*X=6500 Successfully tested fuel cut at 2000rpm. @leon I go to the track pretty often, I'll be at Thunderhill on sept 23 if you want a ride along.

Additionally, here's the Ostrich 2.0 installed on my S130-turbo JECS unit. Have to get some data logging working on Tunerpro, or get someone to drive my car while I play with the tune. Still to be determined if this is worthwhile to get driveability back on a mild hopped up motor.

@Leon I'm wrong! I just pulled apart my S130 1983 N/A A11-652 805 and its JECS with a Motorola 6801 and a Hitachi HN25089LGJ ROM! I thought ZX EFI was L-jetronic, I guess I'm mistaken. Currently going off the assumption they switched to JECS around 1979 or 80, the Motorola 6801 microprocessor was released around 1977-78. Maybe early 76~78 EFI was L-jet, you'd have to pull apart your ECU to confirm. In short- a JECS ECU with a digital ROM can be modified, L-jet is analog and I'm not sure how to go about modifying those. If you do have a digital ECU, the ROM will need the pins identified and remapped to read as a newer style ROM compatible with whatever EEPROM programmer/reader you go with. I used a TL866+ cause they're cheap. Additionally, I'm not certain any of this is worthwhile. I'm having fun playing with tuning mine, but its quite possible that anything beyond stock is not reasonable with these old units. The AFM is a terrible measure of fuel flow, and any modern ECU with a map sensor will run circles around it for tuning ability. After getting the programmer $60, roms and misc supplies $50, spare ECUs to test $100, Ostrich 2.0 for real-time tuning $200, Tunerpro RT(donationware) $40, I'm already in the ballpark of setting up a Microsquirt module. edit, it seems this system is L-jet. Seems everything I've learned previously about these systems keeps turning out to be wrong. I don't know how the older 76-78 systems work, you need to open up your ECU to find out. https://en.wikipedia.org/wiki/JECS

EFI 280Z & n/a 280ZX use analog Bosch L-Jetronic, it's very different from the turbo which uses digital JECS ECCS.

You can dig in yourself if you want, the ROM bin's are attached to the top post. I've been using the address identification from the newer Z31 units as a reference, there is nothing in the hex data on the S130 units similar to the RPM scales on the Z31 units. Romscan is a neat tool to quickly identify 2d lines and 3d maps, I'm using HxD for the raw hex view. In the middle of constructing an excel sheet with the addresses for my 32k roms. ( the data needs to be at the end of the file for the way the rom adapter is setup) The real time on the ostrich unit is simply address hits, since its a rom emulator it can log which addresses on the map were last accessed in memory. Its crude, but better than nothing. Also keep in mind this is the same 6802 processor as used in the 84-86 Z31 ECUs. The main difference I can see is they use a newer IO controller and they're configured for a 28-pin rom. They can access an extra 1K of memory. On the 84 ECU I took apart, the 8K rom contains only code, and the 1KB rom contains only map data. This is different from the S130 ECCS configuration.

After a few times around the block playing with the fuel map I gave up and ordered an Ostrich 2.0 for real-time tuning and address tracing, I should be able to identify the RPM scale that way. Probably going to end up going standalone in the future with something like speeduino, just having fun playing with the stock setup and seeing what it can do. Leon, you're right that the Y axis is RPM, X axis is load which is the same as the Z31 ecus. Unfortunately it doesn't seem the early ECCS has defined RPM and TP scales like the later units. I'm using LiveEdit with custom config currently to modify the maps, but I'm creating a config file for TunerPro RT which supports the Ostrich emulator. Since my AFM calibration is thrown way off from factory and my motor is not standard, any fueling or timing maps I run will not be usable on another L28ET. Edit, While creating the config for Tunerpro I found a 8x8 table in the rom. Not a clue what its for, but its interesting.

Quick update, I've successfully changed the fueling map and started tuning it for my specific engine. I'll report back with my experience once its further along. Its far from an ideal tuning solution without a real time rom emulator like the Moates Ostrich 2.0.

Well, I did want to adjust the fuel and timing maps a bit to get rid of a few drive-ability issues since I'm not running a stock block. Also wanted to pull some timing before turning the boost up again. I also have an 84T ECU I've been scavenging components from it, I'll probably dump the ROM at some point as well.

I have acquired the needed components, thanks to JSM!

Looking for 1982 or 1983 L28ET 280zx Turbo ECU's, preferably a California 1983 model with intact part number sticker. Show me what you got.

Here it is, the moment nobody has been waiting for. Please note this only applies to 82/83 ECU's, I don't know if the 81's are different all I know is they have different injectors. Its extremely easy to chip a ZX ecu. The three ribbon cables from the mainboard to the daughterboard for the dual ROM's need to be removed. F/C-A, F/C-B, and the 3-pin for IC-3. The ribbon cable labeled 'MAIN' is for additional logical circuitry and should not be touched. IC-3 HD47LS20P quad NAND chip is the logic for the memory bus. This chip needs to be moved from the IC-3 spot on the daughterboard to the IC-3 spot on the mainboard next to the 6802 CPU. With the IC-4 spot on the mainboard free of the ribbon cables, a socket or rom adapter can be soldered in place. There are readily available pre-assembled Commedore 64 2364-type rom adapters so that newer 28-pin EEPROM's can be used. I used a 28c256. The IC-4 2364 chip on the daughterboard contains all microcode and map data needed to flash a new ROM. The IC-5 2708 chip is no longer needed. If you already have the BIN's, the IC-4 and IC-5 ROM's on the daughterboard can be left in place, they are no longer used. I'll clean up this post a bit later once I do more testing, but all the basic information is here now.

Edit for latest information; See posts further down for full details on modifying 1982/83 ECCS for re-mapping and live tuning. All information related to reproducing this project can be found on Github. https://github.com/eccs-reengineering/280ZX-Turbo-ECCS Datasheets and other files can also be found on my public google drive. https://drive.google.com/drive/folders/1mRNbCs317YusVA-wutB3DW7AYV1MVt2l?usp=sharing Original post; Thought someone here might get a kick out of this. I just dumped the ROM chips from my 1982 L28ET Manual & Automatic ECCS ECUs. The only data I was able to identify was the timing and fuel maps. The Ignition and Fueling map were identical between Auto and Manual ECUs. There were a few other bits of data that were different but I have not identified what they are. I've attached the .bin file to this post if anyone wants to have a look. 1982 Manual Transmission ECU A18-601-042 2603 1982 Automatic Transmission ECU A18-602-043 2111 Here's some information I've learned about each component while figuring out how to read the ROMs. The 1982 ECCS ECU; (note, 1982 and 1983 ECCS ECM's are interchangeable) Hitachi HD46802P Motorola 6802 CPU varient Motorola 6800 series was fairly common in the late 70's and 80s, disassembles are available although I have not had luck interpreting the code. 6800-series disassembler DASMx, http://myweb.tiscali.co.uk/pclare/DASMx/ Hitachi HD46506 ADU (Analog Data Acquisition Unit) I haven't been able to find any information about this chip other than what it is. 1K-byte 2708-type ROM 1024-word x 8-bits Hitachi HN25089 DIP-24 Contains ignition&fuel map data similar to the design of the dual-chip Z31 & R31 ECCS units, the data is redundant and also contained in the main 8K-byte chip. For more information, see 'The R31 Complication' at https://wiki.r31skylineclub.com/index.php/ECU_Chipping This 1K ROM can be removed, and the ECU will function with the single 8K ROM as long as the IC-3 HD47LS20P quad-NAND chip is moved from the daughter board to the main board. 8k-byte 2364-type ROM 8192-word x 8-bits Hitachi HN48364P DIP-24 Contains all microcode, fuel and ignition maps are on the last 1K of address space. I was able to rewire the 2364 ROM to read as a 2764-type ROM on a TL866 II+ programmer. The adapter diagrams were found on Commedore 64 forums, they also use a DIP-24 2364-type ROM. I have a 28C256 ROM functioning as a replacement with a C64 2364 adapter from Retro Innovations. Attached to this post you'll find two dumps of 8KB bin files from the Manual and Automatic 1982 ECCS ECU's, as well as some representations of the ignition and fueling maps in LiveEdit as well as RomScan utilities. 1982MT_S130_A18-601-042.BIN 1982AT_S130_A18-602-043.BIN

Sorry I hadn't checked this thread in a while. @mods, Necro post reason: found the real solution. Turns out I was troubleshooting multiple issues with similar effects. The issue I corrected in 2015 was a bad negative battery terminal, the bolt was tight but it was loose I could wiggle it around. I've been rebuilding the drive train on my car over the past year, just got it running and the same issue came back. I put on a fuel injection tester & monitored the fuel pressure while driving, it was dipping to around 20psi when the issue occurred. The cause turned out to be a clogged filter screen at the fuel pump!! I feel a bit silly after all that diagnostic work to find such a simple solution, but at least I verified the rest of my setup and learned something. The motor is running very nicely now, after manually re-calibrating the AFM for proper fuel flow.

I need it as soon as possible I'm trying to get my car done within the month. I'd rather not ship a whole gearbox, especially a early wide ratio one since I only need the bell housing. If the price is right and you have a reasonable shipping option I'd consider it.

Troy says 77-83. The reverse location is correct on these years, more modification is required for the older ones which I'm trying to avoid.