Torqbyte Tech Blog

TorqTune MAP Sensor Calibration

Every CM5 and CM5-LT kit includes a 4-Bar Manifold Absolute Pressure (MAP) sensor which can be used in turbocharged set-ups that generate up to 40 PSI of boost.

CM5 uses the output of the MAP sensor to determine the boost level, which is then used to calculate the pump duty the unit will output.

Each MAP sensor is slightly different, so Torqbyte characterizes each and every sensor we ship out and provides the user with their sensor's specific calibration parameters. These parameters are obtained using high-accuracy automated test equipment and are shown on a label applied to each Torqbyte MAP sensor.

The 3 parameters provided on each MAP sensor's label are:

  • Slope of the sensor's output vs. boost pressure
  • Intercept point on the vertical axis, which represents the sensor's theoretical output at 0 PSI of boost
  • Atmospheric pressure reading at the time of the factory test

The figure below shows the first two parameters (Slope and Intercept) graphically:

The slope and the vertical intercept values define the MAP sensor's transfer function (aka line equation aka sensor's output vs. input relationship), which defines its output as a function of the applied boost pressure (PSI). 

You will notice that the output of the sensor is not expressed in Volts although it's typical for MAP sensors to be specified in terms of their Pressure vs. Voltage relationship. The reason is that the CM5 internal processor doesn't work with Volts.

CM5's electronics use an Analog to Digital Converter (ADC) to convert all incoming voltages (including the MAP sensor voltage) into a digital representation of that voltage, which we will refer to as ADC Counts throughout this text.

The third parameter on the sensor's label is used to capture the atmospheric reading (again expressed in ADC Counts) that was recorded at the time of the initial factory test. This is provided so that other atmospheric values can be calibrated out by applying a correction factor based on the difference between the atmospheric pressure at our factory at the time of test and the user's current local atmospheric pressure. This correction factor is then applied to all active boost calculations performed in TorqTune.

The reason that atmospheric pressure is so important in this case is that Torqbyte uses an absolute-type pressure sensor whose output is referenced to an internal vacuum source. However, boost is a relative quantity referenced to the local and current atmospheric pressure, which varies based on geographic location, altitude, season and general weather conditions.This means that the same absolute MAP sensor, installed in a vehicle that's making 20 PSI of boost will generate a higher output at a location with a low geographical elevation and a lower output at a place with a high geographical elevation. Without a way to compensate for different atmospheric pressures the unit would read boost incorrectly which is not ideal for precise boost-based pump control.

Having said that, the CM5 can be used with both absolute type and gauge type pressure sensors. The gauge type pressure sensors base their output on their local atmospheric pressure, so 15 PSI is 15 PSI no matter at what elevation the reading is made. These types of sensors are generally not used in automotive applications, but they are supported by the CM5 and by the TorqTune software (more on this towards the end of this post).

Q: Why do these numbers matter?

A: These numbers are most important to TorqTune. They allow TorqTune to apply proper calibration corrections to its boost calculations that are sent to and received from the CM5. The unit itself, stores these values in its non-volatile memory so they can "travel" with the unit and its MAP sensor, but it doesn't actually use them for anything. This is because CM5's on-board processor doesn't really know anything about pressures or voltages. It relies on TorqTune to program it with correct ADC Count values and it's up to TorqTune to correctly relate the ADC Counts generated by a particular MAP sensor to the actual boost levels that will be seen in operation.

Q: What should be done with these numbers?

A: If you purchased a regular CM5 or a CM5-LT kit your unit will come pre-programmed with the unique parameters for the MAP sensor that was shipped with your kit. The only thing you will need to do is Read these numbers out of the unit so they can be applied to TorqTune's internal boost calculations.

Let's assume that the label on your MAP Sensor said the following:

Slope: 16.848
Intcp: 251.21
Atmos: 254

Assuming you have previously installed TorqTune, connect the unit to your laptop/tablet/PC using the provided USB cable.

Launch TorqTune and ensure it detects the attached CM5. A green LED should appear in the bottom right corner of TorqTune's interface saying "Connected fw" and displaying the CM5's firmware version and unit type (CM5 or CM5-LT):

Next, focus on the Map Calibration section shown on the main Settings tab:

You will see the default TorqTune MAP Calibration values:

Slope: 16.122
Intcp: 222.312
Atmos: 223

These values will almost certainly not match the parameters of your MAP sensor and if you were to proceed with these default values all your boost readings would be wrong. Worse yet, if you were to hit Write or Write All buttons from the top menu, these default numbers would be sent to the unit overwriting the correct values that were stored there at the factory when your unit was shipped. If you ever do this, you can fix things by manually re-entering all the values from the label on your sensor. (more on this later).

Assuming you haven't accidentally erased the factory programmed settings, the next step should be to click the Read button from the top menu.

Now you will see the Map Calibration section get updated with the numbers for your actual MAP sensor that were stored in your CM5 at the factory:

The grayed out Atmosphere parameter in the Factory Defaults section on the left side shows the atmospheric pressure reading measured at our factory when the sensor was tested. However, your current atmospheric pressure may be different, so you can use the Calibrate button to account for the difference.

Note: You should only click the Calibrate button when the CM5 is connected to a MAP sensor. Never perform this step if the unit is out of the car without a sensor connected (for example if you are configuring the unit at your desk without any sensors plugged in). If no sensor is present the MAP analog input will "float" and any random value could get stored as active atmosphere which will prevent the unit from operating correctly.

Note: You should only click the Calibrate button when the engine is OFF. Never perform this step if the engine is running (either idling or making boost). If you hit the Calibrate button with the engine running a wrong value will be stored as atmosphere which will prevent the unit from operating correctly.

Assuming the MAP sensor is connected and the engine is not running, click the Calibrate button.

A warning prompt will appear once again telling you not to proceed if the engine is running:

If you click OK TorqTune will grab a MAP sensor measurement and drop it into the Current Active Atmosphere field on the right. In this example the new Atmosphere reading is 264 ADC Counts.


You should now commit the calibrated values to your CM5 by clicking the Write All button.

Now your TorqTune is calibrated to your unique MAP sensor and also to your local and current atmospheric pressure and all your boost values should be accurate from this point on. If you want to, you can periodically repeat the calibration procedure to readjust everything from time to time and account for changing atmospheric conditions.

At this point you should go to File -> SaveAs to create and save a TorqTune .ttini calibration file with all these settings stored inside. The next time you open TorqTune you should start your tuning session by first opening that .ttini file so that all your MAP settings will be automatically imported instead of the default values that TorqTune will use otherwise.

The last field labeled Deadband is important enough that it requires its own separate blog post.

Q: What if you got a new MAP sensor or what if you accidentally overwrote your MAP sensor's parameters with say the TorqTune default ones?

A: No problem. The solution is very simple. Just as before, make sure that TorqTune is detecting your CM5.

If everything is OK, click the Read button from the top menu:

Focus on the Map Calibration section shown on the main Settings tab:

Click the Edit Defaults button.

A warning window will pop up. Click OK to proceed.

Now the 3 fields in the Factory Default section shown on the left side will become "editable"

 Looking at the label on your MAP Sensor, type in the 3 values from the label to their corresponding fields.

Once all the values are entered, verify they are correct and click the Edit Defaults button one more time

The 3  fields should get grayed out again.

Now click the Set to Defaults button in the Current Active section on the right side.

All the numbers from the Factory Defaults section on the left should get copied over to the Current Active section on the right.

You should now upload the calibrated values to your CM5 by clicking the Write All button.

Finish the procedure by performing a Calibration to the current atmospheric pressure as described above.

What if you want to use your own pressure sensor?

Maybe your set-up makes more boost than the supplied 40PSI sensor can measure or maybe 40 PSI is too wide and you want to narrow the measurements to lower boost values. Maybe you need something that can read up to 100 PSI or even 150 PSI. Once you have the appropriate line equation for your custom sensor, using it with your CM5 or CM5-LT is very easy to do.

Say you are using a CM5-LT in a diesel application and you require a pressure sensor that can measure up to 100 PSI or even 150 PSI of boost. Say also, that you don't want to constantly calibrate for atmospheric pressure and you decide to use a vented gauge-type sensor with a 0-5V output that always represents the actual boost without regard for variations in atmospheric pressure.

Note: You should only use sensors whose output is approximately 0-5V. Never use sensors that are capable of outputting more than 5V as that could damage the CM5's MAP Sensor analog input.

Say that you've narrowed your choices down to something like the Honeywell MLH100PGB06A (100PSI) or MLH150PGB06A (150PSI).

Assume that you finally decide on the 100 PSI sensor and that it has the following output characteristics:

0.5V at 0 PSI
2.5V at 50 PSI
4.5V at 100 PSI

The first thing to note is that this pressure sensor, just like all the others, is defined in terms of its voltage output with respect to applied pressure, not in terms of ADC counts that TorqTune requires.

The conversion between Volts and ADC Counts is quite simple:

To convert Volts to ADC Counts multiply Volts by 204.6
To convert ADC Counts to Volts multiply ADC Counts by 0.00488759

The output characteristics of the 100 PSI sensor above can be rewritten as:

0.5V * 204.6  = 102.3 ADC Counts at 0 PSI
2.5V * 204.6 = 511.5 ADC Counts at 50 PSI
4.5V * 204.6 = 920.7 ADC Counts at 100 PSI

Although you can do this by hand using very simple math, the quickest way to obtain this sensor's line equation is with Excel.

Open a new Excel sheet and enter the boost values in the column A and enter the ADC Count values in the column B. Don't reverse this order or the end result will be wrong.

Select the values entered and go to Insert -> Scatter Chart.

A scatter chart should appear that has the boost values on the horizontal (X) axis and ADC Count values on the vertical (Y) axis.

Right click on one of the points and go to Add Trendline

 In the Format Trendline window that pops up ensure that the following options are selected:

  • Linear
  • Display Equation on chart

Now the chart should now be showing a straight line and an equation.

The number beside the x is the Slope, the number right of the + sign is the Intercept. Since this sensor is a gauge-type sensor we can assume that at 0 PSI it will generate an output equal to 102.3 ADC Counts, as we have calculated before. Since TorqTune only accepts whole numbers in its Atmosphere fields, let's round down to the nearest whole number which is 102.

So for this particular sensor we would use the following parameters:

Slope: 8.184
Intcp: 102.3
Atmos: 102

Then we would follow the same procedure described above under "What if you got a new MAP sensor or what if you accidentally overwrote your MAP sensor's parameters with say the TorqTune default ones?" to apply the new values to TorqTune and upload them to the unit.

If you are working with a sensor that you know puts out 0-5V, but are you are not sure what its line looks like and/or you have absolutely no technical information about its characteristics, there is still hope.

You will need a set-up where you can vary the pressure to the sensor and read that pressure from a known-good pressure gauge (probably mechanical). This gauge should be "trusted" as being accurate. If this gauge is not accurate this procedure will produce unusable results.

You will have to connect the sensor to your CM5 and launch TorqTune.

Enable the data streaming by clicking the Live Updates button ensuring the LED beside it turns green.

On the Live View tab change the way the data is displayed in the drop down menu from Physical Units to RAW Decimal.

This will force TorqTune to display ADC Counts instead of PSI in the field where the MAP sensor pressure is normally shown.

Now that you can view ADC Counts for your sensor, you should first write down the ADC Count value that is displayed when the sensor is just seeing atmospheric pressure (i.e. no boost). This will be your third parameter -> Atmosphere.

After that's done start to slowly vary the pressure applied to the sensor in small increments. This is best done with a decent manual pressure regulator. Pause every so often and write down the pressure reading (in PSI) from your mechanical gauge as well as the corresponding ADC Count value from TorqTune's live view. The more points you collect the more accurate your sensor line equation will be.

When the ADC counts get to about 900 or so you should stop the test. Note the mechanical gauge's reading in PSI. That is around the upper end of the pressure range that this sensor is able to measure.

When you have collected enough points, enter them into Excel and have it generate a line equation as described above. From that line equation you can extract the other two parameters you'll need - the Slope and the Intercept.

Use the procedure above and upload the new values to the unit and to apply them to TorqTune. Don't forget to File -> SaveAs to create a .ttini configuration file.

You're done.

Posted by Torq Byter_ on 24 October, 2015 Read more →

Torqbyte CM5 Water Methanol Safety Features

Torqbyte CM5 and Torqbyte CM5-LT can be configured in many different ways to provide a safety mechanism for almost any water methanol injection set-up.

The most dangerous situation in a water methanol injection (WMI) system is the one where the water meth delivery cuts out under high boost. Over the years, many approaches have been attempted to detect and react to system faults. These approaches included using in-tank float level sensors, measuring pump current to estimate the fluid flow rate, and using in-line flow sensors.

However, unless the WMI controller is sophisticated enough to have an output that can be used to trigger a dump of the excess boost pressure whenever a WMI fault is detected, all that a crude WMI controller could do is alert the driver through some kind of a visual (e.g. LED) or audible (e.g. buzzer) indicator, so that he/she can let off the gas and hope the ECU is able to take the necessary steps to save the engine from detonation damage.

CM5 can be configured to detect system faults using any of the above-mentioned approaches and it also has two General Purpose Outputs (GPOs) that can be used to signal a fault condition to the ECU or to an Electronic Boost Controller (EBC) so the excess boost can get dropped to the wastegate spring level. The CM5 can itself be used as a PID-based EBC. In this case, its ability to drop the boost to safe levels is even more straightforward because it is in control of the boost solenoid and can dump all excess boost directly whenever a WMI fault is detected.

In this blog we will look at three safety approaches that CM5 supports to detect and prevent WMI-related system problems.

Safety Approach 1: Pump Current Monitoring

One of the features that sets CM5 apart from other typical WMI controllers is the user-configurable pump current monitoring. Unlike some of the other WMI controllers that attempt to do the impossible and find a relationship between the water meth flow rate and the pump current, the CM5 only looks at the pump current to address the following conditions:

Condition 1: Is the pump drawing more current than it should be? If it is, this could mean that the line between the pump and the nozzle is blocked, or that an anti-siphon solenoid is stuck in the closed position, or that the pump is seized or corroded by moisture and road salt in set-ups where the pump is exposed to the elements. A condition when the pump is drawing more current than expected is called an overcurrent fault.

Condition 2: Is the pump drawing less current than it should be? If it is, this could mean that the pump has run out of fluid because the tank is empty or the line between the tank and the pump is blocked. It could also indicate that the line between the pump and the nozzle has popped off and fluid is being spilled. A condition when the pump is drawing less current than expected is called an undercurrent fault.

A pump that is pushing fluid through a typical WMI system will draw current that should always fall between some nominal low level, shown as (B) below, and some nominal high current level, shown as (A) below, while the system is functioning as expected. One of the parameters that directly affects the pump current is duty. Clearly when the pump duty is 0% the current will also be 0 A, so there is no point checking for an undercurrent condition when the duty is too low. This duty figure, below which there is little use checking the pump current is shown as (C) below. This value depends on the pump model, diameter of the water meth lines, nozzle, etc. Each of these three points must be determined experimentally for each user's given set-up.


One way to experimentally determine these three numbers is by using the Live View and Output Duty Overrides features of the TorqTune software. By using these tools, the user can command the pump to a certain duty and watch the pump current in the live view to see how that value changes when the pump is full, empty, running through a nozzle, pumping into a blocked line, etc. Clearly you should take steps to avoid any engine damage (like hydrolocking) when performing these tests.

Once the (A), (B) and (C) values for the Main Output Limits or for the AUX Output Limits are known they can be entered into TorqTune via the Settings tab as shown below.

The Time delay field controls how much time between a fault being detected and action being taken will be allowed. Each 100 "loops" to about 4 milliseconds (i.e. 0.004 seconds).

Generally for signalling a fault to an ECU or an external EBC a value of either 0% (OFF) or 100% (ON) should be used to override one of the two low power General Purpose Outputs (GPOs) located at I/O Connector Pin 17 (GPO1) or Pin 18 (GPO2).

Using TorqTune, the CM5 can be configured to set the duty of one of its GPOs in reaction to an overcurrent or undercurrent output fault. This is done via the drop down menus on GPO1 and GPO2 control tabs. In this example let's assume that we want GPO1 to turn on or go to 100% duty (i.e. pull its output to ground) whenever an overcurrent or undercurrent fault is detected on the Main output. To do this we would go to the GPO1 Control tab and select ON when MAIN faulted, OFF otherwise from the GPO1 control drop down menu.

Now whenever an overcurrent or undercurrent fault was detected on the Main output, GPO1 will turn ON (i.e. go to 100% duty) and trigger the ECU or an external EBC to react. 

Although it doesn't have anything to do Water Methanol Injection safety, it's worthwhile mentioning what happens in the Hard Current Limit Zone shown in RED above. CM5's high power outputs are rated for 20A each while CM5-LT's outputs are rated for 10A each. Operating the unit with pumps that exceed these current ratings will eventually cause the unit to shut down the overloaded output. How fast or how slow the overloaded output gets shut down will depend on the unit model (i.e. CM5 vs. CM5-LT) and the amount by which the current limit is being exceeded. The graph below shows an approximate relationship between the amount of overloading and the amount of time, in seconds, it will take for the unit to shut down an overloaded output.

Clearly it is undesirable to have either the WMI pump or the fuel pump shut down unexpectedly during regular operation, but this is the only way the unit can protect itself from eventual destruction by an unchecked overload condition. If the unit continued to operate unprotected during an overload, the pump will shut off anyways once the unit is destroyed by the overload condition. So, it is crucial for the user to ensure the pump(s) used will not overload the unit. If more current is required than the CM5-LT or CM5 are able to supply directly, the user could consider slaving a Torqbyte PM3 to the output(s) that requires more current. A Torqbyte PM3 Pump Amplifier can output up to 36A of current. If your set-up requires more than 36A for your fuel or your Water Methanol Pump it's probably worth taking another look at your set-up and seeing if the current approach is really the most optimal.

Safety Approach 2: Fluid Level Monitoring

The most common way to detect WMI trouble is to monitor a float switch that opens or closes based on the level of the fluid in the water meth reservoir. A smart placement of this switch will see it installed so that it reacts not when the the reservoir it totally empty to a point where the pump is starved of fluid, but slightly above that so a low fluid level condition will be flagged while there is still some fluid in the reservoir.

Since the output of a float level switch is essentially a logic signal (i.e. ON or OFF) it can be connected to one of the CM5's General Purpose Inputs (GPIs) located at I/O Connector Pin 7 (GPI1) or Pin 8 (GPI2) as shown:

Then, using TorqTune, the CM5 can be configured to set the duty of one of its outputs to some user entered value. Generally for signalling a fault to an ECU or an external EBC a value of either 0% (OFF) or 100% (ON) should be used to override one of the two low power General Purpose Outputs (GPOs) located at I/O Connector Pin 17 (GPO1) or Pin 18 (GPO2).

In TorqTune this is done via the Settings Tab. In this example let's assume that we want GPO1 to turn on or go to 100% duty (i.e. pull its output to ground) whenever GPI1 is active (i.e. when its being pulled to ground by the float switch). To do this we would focus on the GPI duty table overrides section. First we would select Override GPO1 when high from the GPI1 control drop down menu. Then we would set the Override duty value to 100%.

Now whenever the fluid level in the reservoir is running low and the level switch closes to pull the GPI1 line to ground, GPO1 will turn ON (i.e. go to 100% duty) and trigger the ECU or an external EBC to react. 

Safety Approach 3: Fluid Flow Monitoring

Another way to detect WMI trouble is to use one or two flow sensors which sit in-line between the pump and the engine and/or the pump and the reservoir and generate a 0-5V voltage depending on the flow rate through the sensor.

Since the output of a flow sensor is a voltage ranging from 0-5V it can be connected to one of the CM5's Analog Voltage Inputs located at I/O Connector Pin 13 (AN_A) or Pin 15 (AN_B) as shown:

Then, using TorqTune, the CM5 can be configured to set the duty of one of its outputs to some user entered value. Generally for signalling a fault to an ECU or an external EBC a value of either 0% (OFF) or 100% (ON) should be used to override one of the two low power General Purpose Outputs (GPOs) located at I/O Connector Pin 17 (GPO1) or Pin 18 (GPO2).

In TorqTune this is done via the Settings Tab and the Output tab of the desired GPO. In this example let's assume that we want GPO1 to turn on or go to 100% duty (i.e. pull its output to ground) whenever AN_A drops say 2.5V voltage (assuming that given our flow sensor an output of 2.5V or less represents an unacceptably low water meth flow rate).

To do this we would first focus on the Basic Config section on the Settings tab. First we would set the voltage range limits for the Analog A input. In this example let's set them to 0V (Min) and 5V (Max). 

Then on the GPO1 Table tab we would set the GPO1 control drop down menu selection to OFF above setpoint, ON below it. We would also set the Vertical Axis drop down menu selection to Analog Input A. Finally we would define the set point values. Since we don't want the engine RPM to be ever be be a factor we would simply enter the maximum RPM value in the Engine Speed field. In this example we are using 8000 RPM, which is the same value we used for the Maximum Engine Speed on the Settings tab. We would set the AN A input field to the flow rate sensor output voltage that corresponds to some unacceptably low flow rate. We are using 2.5V in this example, but that value depends entirely on the flow rate sensor you are using.


With these settings flashed to the unit, GPO1 would be OFF (i.e. 0%) whenever the AN A voltage was above 2.5V and would be ON (i.e. 100%) whenever the AN A voltage dropped below 2.5V. As before, GPO1 turning ON (i.e. going to 100%) can be used and trigger the ECU or an external EBC to react accordingly.

Any one of these features can be used individually or two and three can be used at the same time allowing the user to achieve whatever desired level of safety for their Water Methanol Injection set-up.  

Posted by Torq Byter_ on 18 October, 2015 Read more →

Connecting Torqbyte CM5 to an EBC

Torqbyte CM5 is equipped with an advanced safety feature not found on any other water-methanol pump controller.

CM5 monitors the pump current on both of its output channels and is able to alert the user if the pump current drops below or rises above some user-programmable threshold. A fault condition where the pump current drops below a threshold could indicate the pump is out of water methanol fluid. A fault condition where the pump current climbs above a threshold could indicate a blocked water methanol injection line or even a seized pump (a common occurrence with externally mounted Aquatec DDP 5800 water methanol delivery pumps).

So... what can be done with this feature?

CM5's configuration software, TorqTune, allows the user to configure one of the unit's two General Purpose Outputs (GPOs) to either turn ON or turn OFF when a fault is detected on one of the pump outputs. Since these outputs are "pull-to-ground" types, when they turn ON they are connecting whatever goes there to vehicle's ground.

When a fault is detected on one of the two pump outputs, the CM5's front panel FAULT LED flashes on and off, but that is rarely useful since in most installations, the unit it hidden from driver's view.

At the most basic level, a LED or a buzzer could be connected to the particular GPO to alert the driver that a fault has been detected so that he/she may take appropriate action. However, the reaction time delay associated with having a human in the loop may be way too long to avoid serious problems in a possible scenario where the system runs out of water methanol fluid under high-boost.

If the CM5 itself is configured to perform electronic PID boost control, it will automatically dump all the boost pressure when a pump fault is detected. But what it the CM5 is not used for boost control? What can be done in set-ups where a separate Electronic Boost Controller (EBC) is used?

The solution is fairly straightforward.

In this blog post we will consider how to use Torqbyte CM5's advanced safety features with a popular e-Boost2 EBC manufactured by Turbosmart. 


The approach described here can be used with other EBCs that allow their main boost setting to be overridden (or zeroed) by grounding one of its inputs.

e-Boost2 has two optional wires, Green and Orange that can be used to activate up to 4 different boost set points. By default these wires are not connected to anything (i.e. they are left floating) so the e-Boost2 just uses its boost Set Point 1.

However, if the user grounds (i.e. connects to a vehicle ground) the Green wire, e-Boost2 will start using its boost Set Point 2, or if he/she connects the Orange wire to ground, e-Boost2 will start using its boost Set Point 3.

Table below shows what boost Set Point, the e-Boost2 will use based on that the user does with the Green and Orange wires.

Active Boost Set Point Green Wire Orange Wire
Boost Set Point 1 Unconnected (Floating) Unconnected (Floating) 
Boost Set Point 2 Grounded Unconnected (Floating)
Boost Set Point 3 Unconnected (Floating) Grounded
Boost Set Point 4 Grounded Grounded

Obviously, when a water methanol pump fault is detected, the best course of action would be to immediately dump all the boost pressure to protect the engine. To achieve this, what needs to be done is to set the e-Boost2's Boost Set Point 2 or Set Point 3 to 0PSI and connect either the Green or the Orange wire to CM5's GPO1 or GPO2, depending on what else the other GPO may be used for.

In this example, we are assuming that that e-Boost2's Boost Set Point 2 has been set to 0PSI and that the CM5 has been configured in TorqTune to turn on its GPO2 output when a fault is detected on its MAIN Pump Output.

 All that is required then is to splice together the Green Wire on the e-Boost2 to the Green Wire in Position 18 on the CM5's Input/Ouptut connector, which is its GPO2 output.



Posted by Torq Byter_ on 18 October, 2015 Read more →

Upgrading the OEM Wiring for the New High Power Fuel Pump

You've just installed an upgraded in-tank Low Pressure Fuel Pump (LPFP) in your factory fuel sender basket. You have your Torqbyte PM3 pump amplifier or your Torqbyte CM5 ready to power the new pump, but there is a problem:

The OEM wiring harness that plugs into your fuel sender most often uses very thin 16AWG wires that the manufacturer found appropriate for the amount of current drawn by the factory LPFP that comes with the car. The manufacturer should have anticipated that you will need a larger in-tank pump to fuel your out of control boost addiction and should have installed larger 10AWG fuel pump power wires - but they didn't.

Now what? Leaving those thin factory wires in place will create a bottleneck that will, at best, prevent the you from getting the most out of your new pump and quite possibly cause a fire hazard if the new pump draws more current than those 16AWG wires can safely handle causing them to overheat.

What can you do?

You could simply purchase our VAG Plug-n-Play Adapter Harness or make your own DIY PM3 P-n-P Harness or your own DIY CM5 P-n-P Harness, but given access to the right contact removal and crimping tools you could also rework your factory wiring to achieve the same result.

The male connector on top of the fuel sender is molded into the plastic top of the fuel sender assembly so you can't change it. You also can't drill into the fuel sender cover to pass larger diameter wiring into the tank as you'll never be able to make a safe and reliable seal around the wires. This is clearly an _extremely_ bad idea and should never be entertained.

The issue must be addressed at the connector that normally plugs into the fuel sender. To illustrate the proceudre we'll use the VW/Audi connector Part No. 1K0 919 231 that is found on a large number of VAG vehicles.


This is a hybrid 5 position (aka 5-way) connector made for VW by TE Connectivity (aka AMP / Tyco). Positions 1 and 5 supply the power to the fuel pump.

Step 1 - Remove the old wires from the connector housing

Before attempting to remove the contacts, first remove the plastic retainer (aka Terminal Position Assurance or TPA lock). This is a small pink, U-shaped piece of plastic that is snapped into position around the contacts. You can disengage it (which will allow the contacts to be removed later) by using a very small tipped screw driver and gently pushing it out towards the slot in the side of the connector until it clicks once. Don't remove the TPA from the connector housing or you won't be able to re-insert it once the contacts are put back in the housing. It only needs to disengage one click.

Now you'll need a contact removal tool TE Connectivity Part No. 1-1579007-3 available from many online suppliers such as,,,, etc. This tool is shown below.

When you insert it through the front of the connector, this removal tool will simultaneously compress two spring-loaded tangs that hold the connector in the housing and allow you to (gently) pull the wire and contact out from the back. If you don't use the proper tool at this step you will likely damage the contact and probably damage the plastic housing preventing the new contact from locking in.

Step 2 - Install larger wires into Positions 1 and 5

Here you are faced with two options:

Option A: Quicker and cheaper but with some compromises depending on what you are doing.

You can just buy a wiring repair kit from the dealer that comes with the right terminals and pre-crimped 4mm^2 (i.e. 12AWG) wire. The VW/Audi Part No. 000 979 308 E provides you with a single wire with two terminals (one on each end), so all you need is one of these because you can cut it in the middle which will provide two pieces for the two positions you are trying to fill.

The first compromise with this approach is that you are limited to about 25A of peak current by the wire supplied with this kit. If you are using something like a TTRS pump this wiring will be fine, but if you are using something exotic it may not be enough.

The second compromise is that for whatever reason VAG doesn't include integrated pre-crimped silicone wire seals with this kit. Just look at the wires you pulled out in Step 1 and you'll see they each have a silicone wire seal that is "clasped" and held by the metal at the end of contact that you pulled out. However the VAG wire repair kit provides no silicone seal on the wire provided. We are not sure why VAG supplies these kits without the integrated wire seal, other than that there are many housings these can go into and each housing may require a different seal, but the manufacturer TE Connectivity states clearly that you should never add the seal onto the wire after it's been crimped. Anyways, if you chose to do it the VAG-way you can ask the dealer for a couple of wire seals and and slide them on from the cut wire side after you cut the provided wire in half. DO NOT slide the seal over the crimped metal contact as you will stretch and probably tear the seal.

Option B: MUCH more expensive but without any compromises, this option is probably the right way to go for dealers or shops that might perform this work on a regular basis.

Positions 1 and 5 accept terminals from the AMP MCP6.3/4.8K FLATCONTACT family. These contacts are shown below.

The manufacturer product family drawing can be downloaded HERE.

You can see in that drawing that there are two contacts that will fit into this housing AND accept a single wire sealing system (i.e.a silicone seal).

If using 12AWG wiring you'll need Qty 2 Contacts, TE Part No. 1241416 or 1241417
If using 10AWG wiring you'll need Qty 2 Contacts, TE Part No. 1241418 or 1241419

In either case you'll need a couple of silicone wire seals for the 8.5mm cavity (which is the cavity size of the VW connector at Positions 1 and 5) TE Part No. 1719043-1, but since these TE seals are rarely available anywhere, you can use a Delphi (GM) Part No. 15324990 instead.

To crimp the contacts and the seals onto your wiring you'll need the TE manual crimper Part No. 539635-1 shown below.

However this crimper is supplied blank and you'll need to purchase the crimping dies separately.

For the 12AWG wiring using contacts TE Part No. 1241416 or 1241417, you'll need crimping dies TE Part No. 539956-2.

For the 10AWG wiring using contacts TE Part No. 1241418 or 1241419, you'll need crimping dies TE Part No. 3-1579021-7.

You can get all these parts from your favorite online supplier such as,,,,, etc.

The manufacturer crimping specification can be downloaded HERE.

Once you've crimped the wires and seals as per above specification, insert the contacts into positions 1 and 5 tug on them gently to make sure they are locked in place. Make sure the seal is firmly in the cavity and then re-install the pink plastic TPA lock by applying pressure on it through the slot in the side of the connector until it snaps/clicks into place.

That's all - now you have an adequate wiring connection from the PM3 to the top of the fuel sender. We'll address the upgraded wiring on the inside of the tank in the next blog.

Posted by Torq Byter_ on 28 June, 2015 Read more →

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