Link G4 Link VR4x Setup and Features.

[Malcalmstunt]

Hello Tuners,

I know many of us love our ECMLink V3 ecu's and some of us have switched to Haltech. I am starting this thread to help people learn about the Link Vr4x ECU for the 1g DSM & GVR4's.

To start off, the link VR4x does not have knock control and DBW pins connected from the factory. If you are interested in these features, you must notify your link dealer and have these options modified via jumper wire mod before you receive your ECU. If you are like me and got your ECU first then wanted it after, you will need to reach out to a dealer and schedule a tech support ticket with Link themselves.

Sadly LinkECU does not speak with the general public.

Knock Sensor wiring forum.

DBW Mod information.

Now that is out the way lets get started. I know some information is already here on link so my goal is not to entirely duplicate the information but to simply refresh and provide additional data to everyone. I will add the information in responses.

 

[Malcalmstunt]

Configuration

LinkECU PNP series ship with basic startup parameters. We will need to confirm the following.

- Cylinders (4)
- Engine Stroke Type. (4 Stroke.)
- VIN (If using multiple vehicles.)
- Firing Order. (1,3,4,2)
- - Under the Firing Order Table

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[Malcalmstunt]

Fuel-

Now that is confirmed lets get to the fun part... Fuel.

Under the fuel Setup folder we will go to Fuel Main.

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We must confirm the following settings.

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- Injection Mode (Sequential)
- Fuel Equation Mode (My setting - Modelled)
- - With this setting if you plan on running a single fuel I recommend this setting as it accounts for the following.


Referenced from the LinkEcu

"Modelled - This fuel equation takes into consideration all of the essential physical engine and fuel properties required to calculate the engines air charge and fuel volume.

The Traditional fuel calculation rolled together a lot of the constants like engine capacity, and injector flow into the Master Fuel setting. This was (and still is in a lot of cases) perfectly adequate for achieving an excellent tuning result. However with advancements in information available to tuners and the increasing use of alternative fuels, a more technically correct fuel equation improves the tuners ability to achieve an accurate tune. It also allows easier future changes.

The Modelled fuel calculation mode provides metric settings for all inputs to the fuel equation as well as improved injector flow characterization. The following simplified diagram shows how the Modelled fuel calculation works."

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If you are wanting to run multiple fuels, you will select the "Modelled Multi-Fuel setting.

Modelled Multi-fuel

"Fuel Equation Mode
Modelled - Multi Fuel - This extends the Modelled Fuel Equation to allow for the use of two different fuels. It is common now to run alternate fuels, particularly alcohol based fuels. Often it is a requirement to run two different fuels in the same vehicle (eg for road and race). With the availability of ethanol content sensors it is also common to use a variable blend of fuels.

The Modelled - Multi Fuel fuel calculation mode allows for tuning of the same engine on two fuels, then have a configurable means of blending between these fuels. The system can work from simple applications such as switching between fuels (eg 91 to 98 octane or gasoline to ethanol) right through to a full Flex Fuel application using a continuous measurement of ethanol content."

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I will cover the GM Flex sensor addition later.

To recap the three fuel mode types see below.

Traditional - Used if you have uncertain information on your injectors, want to make a quick tune off of a base map, or are using an existing tune.
Modelled - Use this method if you have sound information about your injectors, and motor eg. (Proper deadtimes, Injector sizing, as well engine displacement.)
Modelled Multi-Fuel - The same as modelled with the additional information of the fuels being used.


- Equation Load Source (Load = MAP)
This is used in forced induction vehicles. This setting will ensure that the fuel pressure is doubled when setting the fuel table load axis to MGP.
It is imperative that one does NOT set the load source as Load = BAP as this is for naturally aspirated vehicles and references the load to the changing atmospheric air pressure.


- Engine Capacity - This will be whatever your engine is from a stock 2.0 to a stroker or destroker. My value is 1997cc
- Lambda Target Table Overlay - (Used to add a fourth dimention to the tuning table. This is used to change AFR's based on altitude or temperatures. This can be activated via inputs.)
- Fuel System Type

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For our cars in stock for MAP referenced is suffice. If you will run a fuel pressure sensor to the ECU you can run FP Sensor.
- - MAP Referenced -
Fuel System Type
For use on a fuel system in which the fuel pressure regulator is controlled by the engines intake manifold pressure. To use this mode, the Base Pressure and Injector Related pressure must be correct.

- - FP Sensor -
For use on a fuel system in which the fuel pressure regulator is controlled by the engines intake manifold pressure. To use this mode, the Base Pressure and Injector Related pressure must be correct as well as a calibrated MAP sensor and FP sensor. Note - This method can ONLY be used in the modelled or modelled multi-fuel modes.


- Base Fuel Pressure (43.5)
- Fuel Density @ 20 C

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- Fuel Temp Coefficient

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- Stoich Ratio - Using 14.7 to show here but Lambda is best for simplicity. As most of us run ethanol we can use the E85 values.

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- Fuel Charge Cooling Coefficient

(I have left this setting where it is from Link. Changing this value after being tuned will throw off your tune. It must be set during setup before final tuning.)


- Min Effective Pulse Width

(This applies to the main injectors being used meaning anu second or third set of injectors will not take affect to this. This setting is not entirely needed but if your injectors come with this information enter it here.)

- Asynchronous Injection

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- Wall Wetting Comp

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- injector Drive Reallocation

Leave Off

- Injector Duty Cycle Fault Value

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Injector Setup -


Now that we have our Fuel Main in place lets setup our injectors. Just under Fuel Main we will see the Injector Setup folder. Click on it and click on the Injector setup wrench.

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You will see the Injector Setup screen populate and this is where you will enter your brand injectors data. For my injectors they are 2,200cc/min. As we previously established your base fuel pressure you will enter this value here. Lastly we must enter our deadtimes on the Injector Deadtime table. Due to losing my deadtime data I went to my ECMLink direct access data for to Injector battery voltage offset information. Due to LinkEcu having more voltage references I had to do the math to find the additional values by taking two number diving by two and subtracting that from the higher number to find the mid point. In addition to this, anything over 16 volts is the same value as I should not see that high of a voltage with my system.

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Now that I have added a fuel sensor to my system I will switch over to Fuel Pressure Sensor referenced Load source. I will touch more onto this subject as I play with the ecu more but for the time being the values input above will do you well.

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[Malcalmstunt]

Ignition -

This section will be short as I do not have much information here setup wise I will attach a photo below as I kept this settings how I received the ECU from the dealer.
We will setup the ignition system under the Ignition Main folder and select Ignition Main. If one needs to fine tune their COP setup we can input individual dwell times per cylinder or across the board. Lastly when we are ready to actually tune our cars we will use Ignition Table 1 to adjust our timing.

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12/30/2025 - Update

I updated my ignition map to be closer aligned to what my previous motor was running. A very reserved map that would be good for me to set a baseline tune.

When messing with the Link ecu tables you can toggle the color gradiant coloring using the "H" key. For ones coming from ECMlink this will be helpful for an easy transition.

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Compared to my previous image you can see that the Y axis is based of of the MGP sensor instead of the MAP. Given the value of anything under 0 will fall under whatever cell the car is running off of, going off the MGP will let you do further fine tuning if different vacuum situations are presented to you or your tuner.

 

[Malcalmstunt]

Engine Protection -

Yayyyy the main reason why I own this thing. With Engine protection it's name is enough for us to know what it does. We can set these limits arout an X and Y axis, RPM Limits off of sensors and speed any many more. Lets dive in!


To access these features we must go to the Engine Protection Drop Down Menu.

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We can setup the type of cuts for these parameters with the settings below.

Fuel - A fuel only progressive cut.
Ignition - An ignition only progressive cut.
Disabled - This mode disables the limiting but leaves the Limit Table allocated so the limit can be turned off without losing the information stored in the table.
Off - Limiting is turned off.

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Now that we setup the type of cut we want lets controlled what the engine protection is based on. With the image below my Engine RPM is based off of coolant temperature. Once I am 176 degrees I can utilize the entire 7500 RPM range but anything above 228F max RPM is set to 3000 RPM to prevent overheating. As well when the motor is cold it will not rev over 5000 RPM. These values can be changed to whatever values you want.

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In addition to this table lets say we want to base our RPM off of Oil Temp we can Right click on the table and pull up the image below.

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Click on Axis setup.

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Where our ECT is highlighted in blue, we can change this to Oil Temp. To do this type in Oil Temp and hit enter.

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We can setup the data in the data to whatever we want just how we did the ECT.


If we want to setup a limit based off of Oil Pressure we will need to use the GP RPM Limit table. First we must enable this.

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We will see the following box populate. Click Yes.

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With the new table we have the following information we must setup.

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Startup Lockout - This is used if our motor takes sometime to build oil pressure.
Activation Delay - The time needed for the limit must be exceeded before the Limit activates. A higher value helps prevent accidental triggers from lower values. Setup with Caution!!!


Here is my Table.
The lock out table will ignore the oil pressure for my new setting of 10 seconds. So if my Oil pressure at startup is at 15 psi it will be ignored for 10 seconds. After ten seconds lets say it reduces to 9 psi, it will be limited to no more than 1500 RPM if the pressure remains at or below 9 PSI for four seconds. From 0 RPM to 2500 RPM. If lets say we are at 3000 RPM and our oil pressure falls below my setpoint of 40 psi to 25 psi. If it stays under 40 psi for four seconds, the motor will turn off.

This table below is an example table I put together for this thread. Your table should reflect your expected oil pressures as well as your build. It is worth noting that the engine RPM is still being affected by your coolant temp settings.

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Axis Setup -

Like previously show, this is where we will tell our engine protection what to base the limits off of. We could easily change our fuel pressure based off of engine RPM's or whatever you see fit.

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[Malcalmstunt]

Sensor Setup -


Now one may think why are we doing this after engine protection, well its because IDK . But here we go.


We have the main page and on this page at the top left we will need to select configuration.

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Now my setup like previously noted is somewhat different but most of these settings will work for you. From the Link ECU factory most of these values are set correct but lets double back and confirm.
We can go to the bar on the left, under analog inputs we will select which analog input and tell it what is there.

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When done we get the following screen.
Here is the Link VR4x Pinout

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AN Temp 2 -

This is our ECT. The settings below if using a factory sensor will work for you. If using anything different you will need to set the Pull up resistor needed and the calibration as well. IMHO it is good to do a crazy fault code similar to the factory ecu show -74 or the insane high value it gives. It is easy to spot.

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AN Volt 1 - This is our TPS and the setup and calibration is similar to how ECMLInk is.

These are my settings -

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Once noted hit calibration and it will walk you through having it closed and WOT and that's all my dudes!

AN Volt 2 - Now I will be looking into this when my garage heats up. Switching from ECMLink we use this pin for flex fuel. Now the LinkEcu requires this be connected to an DI pin. Now that it is an AN Volt pin, we must switch this to a different pin. *** Note I have not confirmed this so if you know for sure your knowledge would be greatly appreciated.*** If I am correct I would be able to use my AC pins to be my DI as I have the alternator relocation.

AN Volt 3 - This is the On Board Map. They come with either a 4 bar map or a bar. My ecu has an 7 bar so this is what I will use.

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Once verified hit calibrate it will show done.

Now I will put this here. When I first got my link ecu this one thing messed me up. My MAP showed me a positive value when off while link shows vac and boost. I always thought I was under boost when I clearly wasn't. I freaked out and tried to find out how to fix this. I then realized that the MGP is what measures your engine vac and boost and your BAP and MAP sensor should read the same if not close values from one another. Don't freak out.

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AN Volt 4 -

This is the pin for your Wideband sensor. If you are using one, you will need to enter the calibration data from your controller manufacturer into a table that the ecu can understand.

To do this we must go to calibration tables
- Linear cal 1
- - Set the name and the voltage range. A being the lowest and B being the largest. Then do the lowest output value and the highest output value. Once complete hit Okay and go to Lambda 1. Once here you will click on the lambda sensor control which is AN Volt 4 and the Calibration will be the cal you use in the calibration table of your choosing.

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Lambda 1 CAN Network based wideband Controller -

I am running a CAN based wideband controller.

To do this, the setup is more thorough and I will keep it short for now. To do this we must tell where the controller is once it is setup.

To setup we need to go to CAN
-- CAN Setup

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Now we need to select the mode which is User Defined and the Bit Rate of 1 Mbit/s with OBD off and the Can Module as which CAN port you are using, I am on port 1. I am using a digital IC7 Das on channel 1 so you can ignore that. You can set up Linl CAN-Lambda in your first channel.

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Once selected, ensure your ID and Format are selected. Hit APPLY and manually cycle power to the CAN-Lambda module. Once done hit ok. Now that is done we must go back to Lambda 1 and select Link Can from the list.

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My Lambda Screen -

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Run When Stalled Note -

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Like LinkECU recommends, I would keep it off outside of cold start tuning. I have mine on due to testing a faulty 4.9 sensor.

Now with all of this noted the rest is self explanatory and I will add more if anyone requests. If you have a MAC solenoid used from ECMLink, it will work on its current pinning.

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[Malcalmstunt]

Boost Contol

This is where the magic starts. With the Link ECU we have multiple ways of contolling boost. Open Loop, Closed Loop, and
Dome Pressure control.

Open Loop - Open Loop Control is when a system goes off of the input it is given and does not check for the results. Eg. ( 40% at 30Hz = 20 PSI. If we told the ecu this, it will use this data and it is up to the user/ tuner to confirm that we are receiving 20 PSI.)

Closed Loop - Closed Loop Control is when a system goes off of the input it is given and measures the results. Once the results are measured, it will attempt to reach the user defined target.( 40% at 30Hz = 20 PSI. If we told the ecu this, it will use this data as well as a boost target, the ecu will use the input results from the MAP, MGP etc and would begin to regulate the boost pressure until it knows that we are receiving 20 PSI.)

Dome Pressure Control - The method of using boost pressure on the top port of your wastegate. This is used to force the wastegate shut, and when the target boost is reached, it bleeds back air allowing the wastegate to open.



For this section we will cover Open Loop Control


In the main folder area we need to go to the folder that says "Boost Control."

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Boost Setup -

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On the line that says Boost Mode, we will see the other options listed that I previously mentioned. From the factory, the PWM output for your factory or aftermarket solenoid is Aux 1.

You can see there's a manual test for the Aux pin which you will hear the solenoid clicking if you were to enable this feature.

RPM Activation -

Any Limit above this RPM setpoint is when boost control is enabled. If RPM falls below this setpoint boost will not be regulated.

MAP Activation -

With MAP Activation, anything below this pressure value will not be regulated, and anything above this value will be controlled.

Deactivation Timeout - Once the boost falls below the users target values, this is how long boost control will remain active until the active status is turned off.

PWM Frequency - This is the frequency your are transmitting to your BCS.A smaller number will give broad boost adjustments while the higher the value is for fine adjustments.

Wastegate Duty Cycle - Wastegate duty cycle percentage controls the boost pressure going into your motor. A value of -100 or 0 means wastegate pressure and anything above that is considered in boost. It is important to take this step slow and make small percentage adjustments in a positive range until you establish control over boost.

Active Tables - Here we can do up to three tables. I am using two as I plan on a high boost map and a low boost map. We can use a DI Pin, or CAN based pin to activate this table. Once this has been wired in, if we were to activate our switch, we would see that the active table status switches from table 1 to table 2.

- Closed Loop Control - Like I previously mentioned, closed loop uses the feedback from sensors and will attempt to get the value to the user setpoint. Below are the new tables for boost target once Close Loop Control is selected instead of Open Loop Control.

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Good to Know - Once you have control over boost, it is important to know that when you are making adjustments to boost pressure that if they are large value changes eg. (10% duty cycle makes a change of 7 PSI.) You can increase your PWM frequency which in turn will lower the amount of boost changed. It may that 7 PSI change into 3.5 PSI for 10%. This is good to know if chasing lower numbers or higher numbers and your Duty cycle is high but you cannot reach your target.

Interlope Between - You have the ability to setup a rotary knob to increase and decrease boost levels from two maps. If we had a rotary knob with 10 different positions, we could set it up to raise boost each level as we increase the knob position number. Position 1 would be 90% of the lower map and 10% of the high boost map. If we were on position 9 then 90% is on the high boost map and 10% is on the low boost map. This would be a good way to regulate power using multiple surface types, weather etc.

We must go into our Boost ratio table and change the information from a Multi Fuel Blend to a AN Volt or a voltage related source. We will setup the voltage to the values from 0% to 100%. It will setup tale a percentage between the two and will control the boost with divided percentage.

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In this table you can see that my duty cycle tables are all at 0. This is to run off of wastegate for my baseline setup. With changing the axis we can base the boost source off of speed or other logged parameters. If we look at the bottom of the screen we have the following.

Boost IAT - With my values at -11 until 32F, the vehicle on paper won't build boost until IAT's reach 32F

Boost ECT - The same as IAT but for the ECT. The motor on paper will not build boost until the motor reaches 178F.

Boost Gear - This option is self explanatory When we know what boost levels we get at certain duty cycles, we input these values here per gear. Doing this applies boost by gear. ***It is worth noting that the gear ratio calculation must be done inside the PC Link software to ensure your boost by gear is setup properly for the calculated speeds.***

I would like to note that these -100% values are removed from the active tables. if I have a duty cycle of 50% and I set my Boost IAT to -25% because it is under temp and my Boost ECT to -15%; we will have a final duty cycle of 34% ( 50+ 40 * - 0.4 = 34%.)

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[Malcalmstunt]

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[Malcalmstunt]

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[Malcalmstunt]

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[GST with PSI]

Wow! Thanks for taking the time to post intricate details and configs. This is going to be a great resource.

I planned to go LinkECU after ECMlink gets pushed past it's limits on my own build. I'm sure I'll come back to this.

 

[mikEclipse99]

When I bought my gvr4 it had link already in it, what a NON user friendly software but once you get used to it its not bad. Nice write up!!

 

[Malcalmstunt]

Wow! Thanks for taking the time to post intricate details and configs. This is going to be a great resource.

I planned to go LinkECU after ECMlink gets pushed past it's limits on my own build. I'm sure I'll come back to this.

Anytime man! I remember reading the forums in middle and highschool so it's awesome to finally be of age and wisdom to add value. Now having a better understanding, I am happy to share information to help others grow.

 

[Malcalmstunt]

When I bought my gvr4 it had link already in it, what a NON user friendly software but once you get used to it its not bad. Nice write up!!

I agree with you 100%. When I got it a year ago, it definitely was a pain. One good thing is that the information they provide in the help section is really really nice!

 

[mikEclipse99]

I agree with you 100%. When I got it a year ago, it definitely was a pain. One good thing is that the information they provide in the help section is really really nice!

The help section is a life saver! That is definitely a really nice feature