PROMAX
Troubleshooting & FAQ
Simple answers first. Detailed troubleshooting when you need it. Use this guide to work through ProMax activation, wiring, TPS/WOT, RPM, pressure sensors, lockouts, progressive control, software, firmware and datalogging.
1. What's Your ProMax Doing?
Pick the symptom first. You do not need to understand every ProMax setting before troubleshooting it.
2. First, Know The Difference
“The ProMax shut off” and “the nitrous stopped spraying” are not the same problem.
The Screen / Controller Powered Off
Start with power and ground.
- Ground directly to battery negative
- Voltage drop under load
- Main battery power
- Loose connections
- Fuse sizing
- Electrical interference
- Solenoid circuit wire size
ProMax Stayed On But Nitrous Stopped
Start with activation conditions and lockouts.
- TPS / WOT
- Fuel pressure
- RPM window
- Wideband / AFR
- Stage enabled
- Gear / transbrake
- Nitrous pressure
- HOLD / RESET
ProMax Main Ground
↓
Battery Negative Terminal
Chassis Ground
Vehicle Ground Lug
Wiring Board
Accessory Ground
3. What Color Is The Stage?
Look at the stage indicator before changing anything.
Grey
The stage is turned off in the setup.
Red
One or more programmed conditions are preventing activation.
Yellow
ProMax is ready but still waiting for the required conditions.
Green
Required conditions have been met and the stage is firing.
4. Detailed ProMax Help
Open only the section that matches your problem.
It Won't Spray Start here if nitrous never activates.
1. Is The Controller Powered On?
If the ProMax itself is not powered on, troubleshoot battery power and the main ground first.
2. Is The Stage Enabled?
A grey stage means the stage is disabled in the setup.
3. Does ProMax See TPS / WOT?
Watch the TPS or WOT input while testing. If the controller does not see the required throttle condition, the stage may remain armed without activating.
4. Does ProMax See RPM?
Compare the RPM displayed by ProMax with actual engine RPM.
5. Is The Stage Red?
Red means a programmed lockout is preventing activation.
6. Does ProMax Show Stage Output?
If the controller says the stage is firing but the solenoid does not operate, move downstream and inspect the solenoid wiring, solenoid and nitrous system.
It Sprays, Then Stops Nitrous activates and then stops during the run.
First Question: Did The Screen Stay On?
If the ProMax screen stayed powered, the controller probably did not lose electrical power.
Instead, one of the activation conditions or programmed lockouts may have changed during the run.
Look At The Stage Color
- Grey: stage disabled.
- Red: stage locked out.
- Yellow: stage armed and waiting.
- Green: stage triggered.
Look For What Changed
- TPS or WOT
- RPM
- Nitrous pressure
- Fuel pressure
- Wideband condition
- Gear
- Transbrake
Why Can It Stop During A Shift?
TPS and RPM can change very quickly during a shift.
If either input leaves the programmed activation range, ProMax may stop commanding the stage.
Check The Datalog
Find the exact point where stage output stopped. Then compare TPS, RPM or MPH, nitrous pressure, fuel pressure, wideband, gear, transbrake and lockout information at that same point.
The Screen / Controller Turns Off Power, ground, fuse, wire size and electrical noise.
Do not use the chassis, vehicle ground stud, ground distribution board, wiring board or another accessory ground for the ProMax main ground.
Why Is Battery Ground So Important?
Nitrous solenoids create a large electrical load when activated. A ground point that appears fine while the vehicle is sitting still may create voltage drop or instability once the system is under load.
Correct
ProMax main ground wire → battery negative terminal.
Do Not Use These For Main Ground
- Chassis ground
- Vehicle ground stud
- Ground lug
- Wiring board
- Accessory ground
- Nearby sheet metal
Also Check Main Power
Main power should also be connected according to the official ProMax installation instructions.
Check The High-Current Circuit
- Main battery positive connection
- Main battery negative connection
- Fuse size
- Wire size
- Loose terminals
- Damaged wiring
- Voltage drop under load
- Electrical interference
Why Does It Work In The Shop But Shut Off During A Pass?
The electrical demand increases when the solenoids activate. A marginal power connection, poor ground, undersized wire or weak terminal may not show up until the system is under load.
Electrical Noise
Keep controller and sensor wiring away from high-current ignition components, capacitors, drivers and other electrically noisy components whenever possible.
TPS / WOT Problems ProMax doesn't see throttle position correctly.
Why Does TPS / WOT Matter?
TPS or WOT can be one of the conditions required before the nitrous stage is allowed to activate.
TPS Reads 0% Or Doesn't Change
- Verify the correct TPS signal wire.
- Verify TPS configuration.
- Watch the TPS display while moving the throttle.
- Inspect the connection for a poor connection.
Checking A WOT Switch
Watch the TPS/WOT setup screen while operating the switch.
If the controller does not see the switch change, verify the switch, required power and correct input.
Vehicle Goes Into Limp Mode
TPS circuits can be sensitive. If the vehicle enters limp mode after the ProMax connection is installed, inspect the TPS wiring and connection.
RPM Problems Missing RPM, wrong RPM or unstable RPM.
Compare The Reading
Compare RPM displayed by ProMax with actual engine RPM.
If the displayed RPM is missing, unstable, approximately double or approximately half, verify the RPM input and controller configuration.
Pressure Sensor Problems Nitrous or fuel pressure doesn't match the gauge.
Start With Sensor Scaling
The programmed sensor scaling must match the pressure sensor connected to that input.
Verify The Correct Sensor Input
Confirm the nitrous-pressure sensor and fuel-pressure sensor are connected to the intended inputs.
Check The Harness
- Sensor connector condition
- Loose terminals
- Damaged wiring
- Shield grounding
- Electrical interference
Why Does The Reading Matter?
If pressure is being used as a lockout condition, an incorrect pressure reading can also cause the stage to lock out incorrectly.
Lockouts Why ProMax intentionally prevents nitrous activation.
What Is A Lockout?
A lockout means ProMax sees a condition outside the limits programmed into the setup, so the stage is prevented from firing.
Nitrous Pressure Lockout
If nitrous pressure moves outside the programmed range, the stage can be prevented from activating or can stop.
Fuel Pressure Lockout
Fuel-pressure lockout can prevent stage operation when the pressure input leaves its programmed range.
Wideband / AFR
Wideband-related conditions may also be used depending on the controller configuration.
Gear Lockout
If the system does not spray in a particular gear, check the gear-lockout setup before assuming the controller failed.
Transbrake
Transbrake behavior depends on how the controller has been configured for the vehicle.
Progressive Ramp Time, TPS, RPM, vehicle speed, MAP, HOLD and RESET.
What Does Progressive Mean?
ProMax can vary the commanded solenoid duty cycle instead of immediately commanding full output.
Time
Output changes according to elapsed time after activation.
TPS
Output changes according to throttle percentage.
RPM
Output changes according to engine speed.
Vehicle Speed
Output changes according to the configured vehicle-speed input.
MAP
Output changes according to manifold pressure.
HOLD
HOLD allows an interrupted time-based ramp to continue from where it stopped when activation returns.
RESET
RESET starts the time-based ramp over when activation returns.
Software, Display & Firmware Laptop connection, screen communication and update issues.
Laptop Won't Connect
- Verify ProMax has power.
- Verify the USB connection.
- Verify the correct ProMax software.
- Verify the computer recognizes the connection.
Error When Software Opens
Connection-related errors can appear before communication with the controller is established.
Display Won't Communicate
Verify controller power and the physical connection between the controller and display.
Problem Started After An Update
Datalogging & Setup Files Find exactly what changed when the problem happened.
Why Datalog?
A datalog shows what the controller saw during the run.
Look At These Channels
- TPS
- RPM or MPH
- Nitrous pressure
- Fuel pressure
- Wideband information
- Gear
- Transbrake status
- Stage output
- Lockout status
What Are You Looking For?
Find the exact point where the stage activated, failed to activate or stopped.
Then compare the controller inputs and lockout status at that same point.
Save The Setup File
Save the current setup before making major changes. A saved setup file is also useful when working with Nitrous Outlet technical support.
Still Need Help?
Verify the ProMax main ground runs directly to the battery negative terminal, work through the matching troubleshooting section, and have your setup file and datalog ready for technical support.