castillaricardo

Noted about the CAN. I’ll have to pass on this option because I want to use CAN 2 for OBD. Ah that’s great! Will do that. Thanks Adam

Yes, power cycling is the only way to disable it at this time. I’m using the input for Launch Control and Gear Shift Control. This is something I would only use at the racetrack, so it would be ok for now. If you see a way I could disable it without cycling power then that would be sweet! I will eventually purchase a keypad or a CAN switchboard where I can wire buttons to but wanted something simple like this in the meantime. To clarify, LC only activates when I’m stationary and hold the clutch because of the disarming speed lockout. Without the switch GSC would trip on me sometimes in spirited drives which is why I wanted this switch.

Hi all, I've wanted to setup a hidden switch to enable launch control and gear shift control. I decided on holding the brake and clutch for 5 seconds with the engine off as the switch in a GP Output and the next step was to make it latch. My latching solution was to use a math channel with the pk function, and another GP Output that watches this math channel and the clutch switch, which then feeds the state to the motorsports features. This seems to work well but I wonder if there is a more elegant solution that uses less GP Outputs and no math channel? Maybe using the CAN bus somehow? I played with feeding a CAN DI set to latching but had no luck transmitting and receiving a message in CAN to do this. If someone has a different method or can tell me what I did wrong with CAN I would appreciate the lesson. Thanks, Ricardo Current settings: These are the CAN settings I tried to feed a CAN DI from a CAN AUX. Channel 4 and Channel 5 are using the same CAN ID. There were no errors in the runtime values but CAN DI 1 didn't get a status change. I also tried width of 1, 2, and 8 bits: Stream 2: Stream 3:

Yes, MAP referenced is the correct setting then. I don't know what the fuel pressure is on those, maybe Adam or Vaughan know or you could look for a service manual that fits your car. About the boost control setup. What I meant is that you should set the Wastegate %DC 1 table to all 0s until the fuel map is tuned. Yes on the fuel cut table. Do you have a Plug-In NB1 G4X? If so, this is the cable you'll need for CAN: https://dealers.linkecu.com/CANJST4. Pinouts are on the site and Help page. I think you have a vacuum leak, your throttle is not closing fully, or your idle valve is not closing enough. Your idle valve at one point is at 0% duty cycle which should have stalled the motor but it is getting air from somewhere. The extra air is making it idle too high after you blip the throttle and that's why it isn't entering into the closed-loop idle after (Idle Status hangs at RPM Lockout). Also, add your current tune to the Google Drive link.

Don't assume that it is. Look at your engine bay, right side of the car, and check if you have one fuel feed and one EVAP, or if you have one feed, one return and an EVAP. See below for some examples. I haven't seen a return-style NB in person, but it should be similar. Return style: Returnless style: The EVAP line is the one little pipe sticking up that's disconnected in the second picture. As for your tune: - I don't know what the fuel pressure is for a return system, but the returnless is expected to be 400kPa/58psi. I'm not sure it matters, but I like having the settings correct. - I wouldn't use someone else's boost control duty cycle unless you have the identical valve and overall setup and have the car tuned. For now, just have it set at 0 duty-cycle and tune on wastegate pressure, and setup a MAP Limit right above what your wastegate spring is. - In your log, the overrun fuel cut is still engaging at idle, causing the oscillations you saw as it pulls and adds ignition timing. Set it to disable at 2000RPM and your idle will likely improve. - Your idle valve needs tuning. Start with 500Hz frequency, and you could set it to closed-loop. Your dashpot should likely be lower as well. - You really need to have a wideband connected to the ECU. I strongly suggest you get a CAN based controller. - Consider a fuel pressure sensor. Link can use it to adjust fueling if something goes wrong with the pressure. Take a look through the help file. It really does a great job of explaining every setting and is one of the best things about Link ECUs. Modelled fuel mode has a few moving parts, but really go through the help file as it will explain all of it. For example, your IAT Correction, but modelled mode has a charge approximation table that takes care of the IAT corrections if setup correctly. It's up to you and your tuner how to set this up, but just food for thought. Your car starts and mostly idles so that's a good start.

I did have an exhaust leak exactly as you described. I couldn't source a new gasket before the trackday so I grabbed a generic gasket that fit and made it work. No leak for the weekend. So the weekend's results. The tank pressure showed 1kPa after my hotlaps in 100+F ambient temps, so good result by fixing the exhaust leak. Gaining elevation does increase the tank pressure to about 3-4kPa with my current purge control. I used a 4D fuel correction to compensate for the richness caused by the purge. After ~300 miles of mountainous driving I'm satisfied with the results. I can smell fuel as I gain big elevation but goes away after some cruising, so maybe I just need to make the purge more aggressive and should check that the carbon canister is still in good condition. I will also move the purge wire to a PWMable pin later, I just wanted to test this out quickly. I also played with the CDCV after hard driving/tank hot. Closing the valve increased pressure, opening made it stop increasing. I haven't had a chance to play with closing it as the purge is active, but I imagine that's not a wanted state? To recap: I had an exhaust leak making the tank hot. Elevation gain does increase my tank pressure. Used Mazda's Tank Pressure sensor calibration and seems to be accurate (was using the wrong calibration earlier). Purge control is working, makes the car rich as it activates. If anyone has any further feedback I would love to hear it and learn more, but I think I have resolved my issue for now. Here are some pictures of my current settings for anyone that may want/need to setup a similar control:

The dashpot is meant to hold the RPM above your idle target during open loop, so during the lockout conditions. The idle valve or throttle in your case will be held at throttle target+base position+dashpot+idle up corrections (Fan, AC, etc.) during the lockouts. It seems you already understand that, just wanted to clarify it. I personally use the "In Gear" lockout instead of speed so it goes into closed-loop idle if the car is coasting in neutral. This really only happens when someone else drives the car, I'm always in a gear while coasting. It works well for me, but requires a neutral and clutch switch to work. Based on some of Adamw's advice to others, I'm using a correction of 8 at full cold for acceleration enrichment on top of the wall wetting settings. Note that my engine has injectors further from the valves than most but I think the wall-wetting settings compensate for that. You might need more Accel Cold Correction in the colder side of the curve.

Ah, color me schooled. Thanks for that. Then yes, he’ll need to verify his setup.

The basics look ok, except for your fuel pressure settings. NBs use a returnless fuel system but yours is set to MAP Referenced at a lower pressure than stock. Is your fuel system modified to fit these settings? In your log the Overrun Fuel Cut is activating at idle, and the Fuel and Ignition tables need boost rows. You mentioned 1200cc injectors above, but the settings have 700cc. If the previous owner was running lower pressures as your map suggests that might explain why he used that number. You should look into this too because it would affect the whole map.

Have you sorted this @Venomancer? The only help I can offer is to use the timing from the ChromedECU ROM and reduce a few degrees off the boost areas. Datalog with those and note the knock threshold numbers. That should give you a safe threshold curve to start with. Unfortunately my stealth is not near me, otherwise I would offer to do a few pulls and datalog the spark timing I get from it. I could try to look for some old logs and get a histogram going if you haven't figured this out yet.

I've been busy with other projects and haven't checked the exhaust for leaks yet, but I will tomorrow. Hadn't even looked at the car until today. I have to get it ready for Saturday trackday and exhaust leaks are in the To-Do list. Do you mean in the stock ECU? If so I have no idea. I haven't found much about the stock PWM logic other than it does PWM during cruise states. As for the logic I was using above, the valve was open anytime I was cruising, regardless of tank pressure. I'm not seeing the tank pressure move at all, so I'm starting to second guess the scaling I found in the manual. Just today I figured out a way to PWM the valve using a math channel. After driving the car around a bit the richness oscillation is gone. The car still runs ~9% richer than it used to when the purge is active but CLL took care of it. The formula I'm using is "sin(a*10.3)-0.5", where "a" is cnt(a), and cnt(a) is counting when the "Cruise" GP Output turns on (RPM>2400, TPS>2%, MGP< -10kPa).

Thank you both very much. I got to drive the car on a 170 mile trip with a mocked up EVAP system plumbed in. Stock solenoid and overflow canister connected to the vacuum manifold I use for the brake booster, MAP, and IACV. In this trip I found the EVAP made the car pig rich anytime it opened, especially after a big elevation climb where I leave the car at 4k-6kRPM for a while. Specific example is the hill up to town where I go from 5600ft to 7200ft. After this climb, Purge active made the car 15-20% richer, then CLL made the Lambda oscillate a lot which affected drivability. I also found I had to close the purge valve on overrun in addition to the other conditions (at idle, near BAP, engine cold). That said, the tank was nowhere near as pressurized as other times. More testing needed, especially on a hot trackday. It seems PWMing the purge valve is necessary to control how rich EVAP makes the engine. It really caught me off-guard how much of a difference this made at part throttle. @koracing I've tried to find a way to use a math channel as you suggested, but I can't think of it. Could you give me an example? Otherwise I'll plan to swap the wire to a PWM capable output. @curly That counts as an expert to me! So yes, I can hear the ECU clicking the purge and the CDCV. Link doesn't have an output for the TPCV, but from what I've gathered that one is a last resort vent valve when pressure goes too high. The stock ECU closes the CDCV when it checks for leaks in the EVAP system. The CDCV is closed, a small vacuum is pulled with the purge valve, and the ECU checks the output of the tank pressure sensor. If it's out of spec, a CEL is thrown (small EVAP leak, or large EVAP leak, depends). So the CDCV is normally open until the ECU actuates it as you pointed out, so I left it open in my testing above. Tank pressure stayed at 0kPa using the scaling I found in the service manual, so it most be working? Here is the logic I'm using for the Purge Control at the moment.

I'll get under the car on Friday and look for leaks. I've been going through the service manual and many forum posts to understand how this EVAP is supposed to work together, but I'm seeing conflicting information and could use a sanity check from more knowledgeable folk. Turns out the manual also has expected values to voltages for the Fuel Tank Pressure sensor and Fuel Level, which is nice, and my previous scale was very wrong. The NB1s have a more complicated system than NAs with 2 valves in the rear (canister drain control valve and tank pressure control valve), a rollover valve, and the purge valve in the bay. The service manual also indicates that the purge valve is supposed to work on PWM, not just on/off. Aux 12 is not selectable for PWM, will it be ok if the logic is on/off? My main doubt is whether the CDCV should be open or closed when the purge valve is active, and is it ok for the ECU not to control the pressure control valve?

It seems the fuel tank pressure increasing correlates to how hard I drive the car and not so much with altitude, validating what curly said about my exhaust possibly heating the tank and no proper venting in place? It's possible there is an exhaust leak back there, and the muffler is slightly higher than stock and could be rubbing a bit. The purge control logic through a GP output seems to work as expected, but I don't have it plumbed into the manifold yet. I hope this helps the situation once that extra manifold arrives and a vacuum gets pulled on the EVAP line. Does this seem sound to you @koracing @curly? Log: https://1drv.ms/u/s!Amu_1gWOWFlvoAzlo9PnN718rn64?e=h0dN8D

If closing the idle valve while cruising or WOT has the possibility to help reduce noise in the MAP signal of ITBs I would like to test it.

Awesome to see a 3000GT getting a Link. Do you have a thread on 3si or here about the install? I would like to checkout your progress and outcome.

@koracing yes it’s definitely getting pressurized. When I open the cap after going higher elevation there is at least a couple of PSI in there. I’ve ordered another vacuum manifold to use for emissions, PCV and EVAP for now. Should be here this week. @curly I saw your response about AN Volt 8 but it’s on a separate thread. I configured the input and it has a reading! I have no idea what the correct values would be so I scaled the 5 volt value until it read BAP (with the cap off and poking the breather). Apparently 155kPa at 5volts? I’ll drive the car tonight and see what the readings say.

Ah, yes. Gotta figure out a way to plumb the canister now. Any idea why fuel would be coming out of this line though? I understand fuel vapors come out of it, but having actual raw fuel coming from it doesn't sound normal.

Have you verified that the injector deadtimes are correct? If not it would make the modelled mode incorrect once it starts doing compensations. Also, since you're using modelled, you should disable the IAT corrections and use the Charge Temperature Approximation Table, otherwise it compensates twice. Similarly for the Warmup Enrichment. I personally use the overlay target table to run closed loop during warmup, and target richer AFRs until up to temp.

I just noticed that the Purge Aux function works under 90kPa and off idle, which in my case will be always active off idle because of the altitude (78kPa BAP). Is there any way around this? Maybe a feature request?

I think I need to sweat this a little bit. In a recent trip through various Colorado mountain passes I ran into fuel pressure problems. The fuel got very hot and it was coming out of the stock EVAP line in the engine bay that I had then uncapped. As a result my fuel pressure started fluctuating and the ECU overcompensated and the car ran rich, which is good. Opening the fuel cap released the pressure and I got to a hardware store, got a cork to cap the EVAP line, and continued my trip and racing with no further issues. After doing major elevation gains I would stop and depressurize the tank, so not ideal. So I guess I'm dealing with a fuel vaporization problem but I have not clue where to start diagnosing. Could someone give me some pointers on this one? I still have the stock canister in the rear of the car, under the tank, but no purge valve. I see Link can do basic control of one so I could find a way to retrofit it but I'm not sure this is the issue.

Thanks! I tried a set of 35mm that came with the ITBs, and these 60s. Keith Tanner did testing with the TWM throttle bodies on a BP years ago and found that taller stacks were overall better in this engine. Since I don’t have a dyno easily available I just went with the longest I could fit. There was a big increase to the VE table with the 60mm trumpets between 4400 and 6500 rpm. The VE then drops off a cliff after 7000rpm which I guess is expected. The longer stacks also sound more snorty at part throttle which I was very happy for. After talking with Keith this weekend, I’m going to try and design a set of twisted stacks BMW style.

This past weekend was Flyin' Miata Summer Camp, and part of the event was a trackday at Grand Junction Motor Speedway. I drove the car over 900 miles round trip and snatched 10th place out of 32 cars which I'm very happy with. Something is up with my tank getting pressurized though. It got a little unhappy at 11,000+ft of altitude a couple of times.

Please post a log of it happening and your tune file. It could be your idle base settings, IAT corrections, too aggressive PID settings for idle control, or some other setting causing it to run lean at idle or locking the idle control.

This is Scooter, my 1999 NB Miata. Acquired in August 2017 as an OEM+ car that became an ITB learning project. Quad throttled since 2021 and used an MS3Pro for a while before making the leap to a Link G4X. I'm very grateful to KORacing for getting me up and running and answering all my questions. This is the best the car has felt in years. The G4X ECU is setup to run modelled mode with MAP as the Load source and TPS on the Fuel, Ignition and Target tables. The MAP is jumpy but the car runs great. There are fuel pressure, oil pressure and oil temperature inputs with safeties looking after the engine. I've also played with Math channels, virtual outputs and CAN Auxes to setup custom functions such as virtual fuel tank resets, flood clear, knock CEL and an extra idle up when the second fan turns on. Some virtual outputs also feed the GP RPM Limits for AFR and Fuel Pressure safety. I've also played with Launch control and gear shift control. Both worked really well but mechanical sympathy doesn't let me use them often. The engine runs sequential ignition with Toyota COPs and sequential injection with DW 550cc injectors. KORacing setup the injector deadtimes for me because the data I got from DW was far from correct. I intend to setup a Flex Fuel sensor and run modelled multi-fuel for the new-to-me VVT engine build. The goal of Scooter is to be a fun fizzy street car with track capability. It competes in ABQ Super Lap once a month, and we will soon make the trek to Colorado for trackday at Grand Junction Motor Speedway during the Flyin' Miata Summer Camp. I'm excited to be part of the Link community and continue learning with this car and ECU. Stockish power, 2250Lbs, 7500RPMs. Snorts for days. Current specs: Electronics: - Link G4X Plug-in ECU - Hybrid Alpha-N. Self-tuned - CANChecked MFA 2.0 center gauge - 14point7 Spartan 3 CAN wideband controller Engine: - Stock BP-4W - 36-2 trigger wheel - Fluidampr balancer - DW550cc injectors to accomodate future flex fuel Intake: - 45mm Borla Induction Throttle Bodies - Custom 60mm carbon fiber polycarbonate velocity stacks - NB Miata idle valve Exhaust: - NB2 tubular headers - Cobalt midpipe with catalyst - Stock muffler with a cartoonish tip that the car had when I bought it Cooling: - Supermiata radiator - FM coolant reroute - 180F thermostat Suspension: - Xida Race coilovers 800/500 (14k/9k) - R-type tie rods - Sadfab bronze bearings - Energy Suspension Poly bushings Chassis: - Paco motorsports strong arms - FM butterfly brace V2 - Front strut bar - Blackbird Fabworx GT3 Rollbar Brakes: - FM LBBK - Centric blank rotors Interior: - Schroth 4-point ASM harnesses - MPI Mazda Cup steering wheel - NRG Keyway type quick-release - Carbon fiber Lotus Exige Replica seats