Posted on 61 Comments


The FiTech ECU for Go EFI systems has a special driver circuit that will drive the fuel pump directly, which means that an external relay is not needed. This driver circuit allows both PWM control (pulse width modulated), and direct internal relay drive of the fuel pump. This allows the voltage to be reduced when the fuel demand is low, such as at idle and light cruise.

Pump Prime time = At Key On, the pump is turned on for this much time, which allows the throttle body to be purged of air pockets, and for the pressure to be built up to the normal operating pressure.

TPS for PUMP ON = If the throttle is opened above this position, the internal relay is turned on to supply full power to the fuel pump.

RPM for PUMP ON = If the RPM is above this speed, the internal relay is turned on to supply full power to the fuel pump.

PWM Low Flow = When the fuel flowrate is low, and all of the other conditions for allowing PWM control to be met, this is the percentage of duty cycle that is used. Set this such that fuel pressure doesn’t drop below the rated fuel pressure of the system.

61 comments on “FUEL PUMP CONTROL

  1. Is there an option to turn off the pwm control and just directly power on an external relay? Current setup has an external relay powering a aeromotive stealth in-tank hi pressure fuel pump/sump setup. If not how would you recommend I set up the feed power to pump

    1. At the factory setting for the PWM in the EFI is set to be full on and a relay can be used.

  2. What amperage load is the internal relay and PWM rated for?
    Is a diode needed to prevent feedback or is this taken care of internally?


    1. The limit of the pump line is 15 amps. No diode is needed.

  3. is the fuel command serviceable? as if the electric fuel pump quits?

    1. The Command Center is serviceable and we do offer replacement fuel pumps. (pt# 40102)

      1. I just installed the command center. During the first run test the car run out of gas. After that the pump did not started again. I was told by the installer that he did not disconnect the electric power to the command center while the deposit tank was refilling. Is it posible that the pump has been damaged?. Do you have any recommendation to make it work or where to look?.

        1. If the Command Center was not primed it will cause harm to the fuel pump. Please call us and we will help you would with a solution. 951-340-2624

  4. Will the PWM run 2 bosch 044 pumps?

    1. The EFI system will run PWM for a pump that draws less than 15 amps. Two Bosch 044’s will run more amperage so you can NOT use the PWM and you must use a relay with the system.

  5. The PWM can control only ONE bosch 044 pump is that correct ?

    1. The PWM will work with a pump that draws less than 15 amps. Anything over that will damage the unit.

  6. Could a solid state relay be used to keep the pulse width modulation fuel pump output feature of the ecu (but on the control side of the relay) and run a higher amperage output to the pump without drawing that amperage thru the ecu? If so what would the operating frequency requirement of the solid state relay be?

    1. This is an interesting idea. We have never tested this so we could not say whether it would work or not. The PWM of the ECU operated at 1khz.

  7. When using the relay, where does the Orange wire connect?

    1. The orange wire provides 12 volts to turn on a pump. When using a relay with the EFI system the orange wire will connect to the relay trigger circuit (pin 85 or 86) and the other side of the circuit needs to be grounded.

  8. i have a Spectra EFi fuel tank with a Spectra in tank fuel pump what should pwm settings be?

    1. You need to contact Spectra to see if their pump will work with PWM (pulse width modulation) systems. If it will you can decrease the value to just before the fuel system starts to lose fuel pressure during idling then increase the value by about 5. This will make the pump run as slow as possible while still maintaining fuel pressure.

  9. I am using the Edelbrock 3605 fuel sump. what should the PWM be set to?

    1. You need to contact Edelbrock and ask if their pump work with PWM. If yes you lower the PWM value to just before the fuel system can not maintain pressure.

  10. I currently have an aeromotive part number 11569 in tank pump installed in my vehicle. Will this pump be compatible with the go efi4 30002 system, and will PWM and current be okay for the fuel pump circuit of the
    ecu? I would rather use PWM if possible. I know aeromotive states that this pump will work with PWM applications, but not sure about current. Thanks.

    1. This fuel pump will work with our system. The pump wire can support up to 15 amps. PWM is not set from factory so out of the box it is on 12 volts. If Aeromotive says this pump can support PWM have at it! lower the value to the point you start to loose fuel pressure then increase the value by 5 to 10. You will need a pressure gauge to do this.

      1. How do I lower the value in the handheld controller? Would this be the PWM low setting. I do not need full speed of the pump at low fuel demand ie. at idle and light loads. Also will I need to change the other PWM settings that are available or only the low setting? Thanks again for your time.

        1. We only present the low PWM setting from factory. Its in the Engine setup page called (Pump PWM If FCC=40) and this value is set to 74.9 default. If you want full control of pump speed you will need to access Fuel Pump Control in the Pro Calibration which can be turned on in Display Setup.

          1. Correct me if I’m wrong, but I read in other posts that the fuel pump circuit for the goefi4 system will support up to 15 amps max is this true? Also I contacted Aeromotive about the fuel pump I am running and they said that with that pump @ 58psi I will be pushing the limits right at 15 amps. So with that said can I safely use the fuel pump circuit from the ECU to trigger an external relay or do you think I would be safe running that close the limits of the fuel pump circuit? Also if I use an external relay triggered by the ECU will there still be voltage control to the pump, or will it run at full power all the time? Thanks for your time.

          2. You can use the pump directly hooked up to the EFI. We have tested with this pump. Also you can if you want too use a relay. When using a relay the pump will run full on all the time.

          3. Sorry to be such a pain in the butt, I only have one last question for you and that is— what wire size do you recommend running to the pump? I know the wire size for the fuel pump circuit on my vehicle is probably no larger than 14 gauge. Aeromotive recommends running 10 gauge wire to the pump but that is to get full battery voltage/ current to the pump from an external relay. Do you think I would need this big of a wire if I am using ECU control of the pump. The reason I am asking is that it would require modification to my fuel pump module to get a larger wire to enter the tank and hookup to the pump. It looks as if the wire size for the fuel pump circuit from the ECU is 12 gauge. Any recommendations will be helpful in aiding my setup. Again thank you for your time and quick response to my inquiries. Customer service is excellent.

          4. You will be fine using the same size or larger gauge wire from the EFI system which is 12 gauge.

  11. Hi, we have the Fitech 1200 Power Adder, and we have been getting our Hot and Cold Starts alot closer….. but we are having a problem with the fuel pump running…. it has done it twice now….. the first time it happened, I was running it, and shut it off, took the key out, and noticed the pump still running! We had to unhook the battery to shut it off, and it was back to normal after that…. today I started it and ran it for a few minutes, I shut it off, the fuel pump and every thing shut off, and I was still sitting in the car writing down my changes I had made on a piece of paper, when all the sudden, the fuel pump kicks on and starts running again, Key Off. Had to disconnect the battery again, and that turned it off…. it seems that the Internal Relay or Harware is doing it on its own! We do have it ran through an external realy as well, but that relay gets its power from the Fitech….. so it has to be the Fitech powering it, even when the key is off, right? Please help!

    1. This is normally caused by a loss of either ground or power for a moment, or a random spike through the ignition system (if the car is running). This can cause the ecu to go into a fault loop and make this situation happen. I would recommend checking your grounds from the engine to your battery as well as the power wires to the system to make sure there is good continuity through all of them. If this does not work then we may need to reset the ECU to do this please follow the directions below.

      Resetting to a stock calibration:

      From the main menu go to the very bottom and select Write Cal To ECU. Once in this menu scroll down to the second to last selection, it should say Default v8 T195. Once on this file select it and it will download to 100 percent. After this is done it will revert to the main menu. Now go to Go EFI Initial Setup, then Engine Setup, now input all of the parameters that are needed for your application, making sure to save each one individually.

      After you have entered your information and saved it go up and select Dash Board. Once in dashboard turn the ignition key off and wait for all the data to black out. Once this happens turn the ignition key to the on positon and start the car.

  12. Any problem with using copper wire to extend your aluminum wire to the tank mounted fuel pump?

    1. We actually use copper wire… We tin the ends of our leads.

  13. I assume that I need to run a return line to the fuel tank as you show for an inline pump. Does that not effect the modulated control?

    1. Yes a return line is needed. The PWM feature will slow down the pump but it will not control pressure.

  14. I have the 30002 unit and am using the GPA-4 pump from Tanks Inc, which says it should draw about 10 amps at 58psi on a 12V system. The orange wire from your harness is 14 gauge, but to run it to the in-tank pump, the run will be 15+ feet with all the bends and turns. Do I extend the orange wire with more 14 gauge? I don’t mind using a beefier wire (e.g., 10 gauge) from the pump, but how do I hook it into the orange 14 gauge wire? I know I can use a relay, but I’d like to be able to use the ECU modulation feature. Is this possible, or is the relay the only way to go?

    1. Using the same gauge wire or larger is fine. The circuit is rated for 15 amps so going straight to the pump is okay. You can also use a relay if you would like.

  15. I’m running a dual fuel pump setup in a boosted app – where the 2nd pump is activated off a hobbs switch. Ideally I would like to ditch the hobbs switch and use the fitech to activate the 2nd pump. Is this possible, using the orange wire, to activate a (2nd) pump at X-psi of boost?

    If no, is there a more elegant way that you could recommend to run dual pumps with the fitech unit? I’m running (2) Aeromotive 11540 pumps. I do not believe the fitech could control both pumps via the orange wire to due amperage concerns.

    1. The EFI system can NOT do what your asking. Unfortunately I dont have a better option for you. The EFI will support up to 15 amps on the orange (pump) wire.

  16. Can your Command CENTER #40003 be mounted next to the fuel tank, rather than in the engine compartment. My fuel tank is actually in the truck of my car with an external fuel pump feeding the existing carb on the engine.

    1. It could effectively be mounted where ever. You just need to supply the system with 4-6 psi of fuel pressure. Usually they are mounted next to the radiator.

      1. I have no room under the hood to mount it there. The only room I have is in the trunk where the 10 gal fuel tank is mounted with the existing electric fuel pump, Its a long run from the trunk to the engine compartment, as I have a 351 Ford V8 stuffed into a 1926 Ford Coupe…. Thank you for your assistance

  17. I have the Coach Controls Coupe-23 wiring kit that powers the fuel pump through a built-in relay that is triggered by the ignition. What do I do with the orange wire since it won’t be used for the fuel pump? Thanks for answering my question.

    1. I would give the EFI control of the fuel pump. It will cycle the pump as needed and will shut off if a RPM is lost.

  18. Getting ready to purchase the 30004 PA system. I want to replace my fuel tank and there are three options that I’m considering. The Aeromotive kit, the Tanks kit and the Holley Sniper kit. I want to utilize the PMW function as well… which one of these kits works best with your system?
    Aeromotive 18317, Tanks TM37B-T Kit, or Holley Sniper 19-05…I have a 66 Chevelle SS big block

    1. It seems like all three of them should work. You would ultimately ask the manufacturers if their pump can be ran on PWM.

  19. Is it possible to use the Command Center fuel pump (40102) stand alone in place of a standard in-tank pump and power it with the Go EFI 4 – 600 orange wire directly? I ask because I’m going to replace my Q-jet with the Go EFI and I’m also replacing the fuel tank and sending unit (1978). I’m debating between replacing the existing mechanical pump with an in-tank unit or supplementing the existing mechanical fuel pump with the Command Center. If I go to an in-tank setup, this would seem better than driving a different after market pump, such as a Aeromotive 11569.

    1. It is possible to use the 40102 fuel pump inside a tank. You will have to build a hanger to hold the pump inside of the tank.

  20. I have a 1200 power adder with the Aeromotive stealth tank and an external relay. Do I set all 3 pwm settings to max? Is there anything else I need to change for this setup?

    1. You can leave the PWM settings where they are. They are set to run 12 volts.

  21. How can i turn off the PWM function.. i have go through the menu and cant find any option on it. I need to run relay to operate my panthom fuel syste.


    1. If the Pump PWM is set to 75 or more it is basically off.

  22. Planning to install a In-Tank Pump to feed the 600PA unit and need to upgrade the factory EFI Pump. (upgrade wiring as required)

    I was either looking at your replacement pump #40102 for the FCC or as mentioned in previous post the aeromotive11569 installed into the fuel tank to the rear of the car.

    What are the specifications on AMP draw for the #40102 ? will the distance from the ECU to the Tank pose a problem because of distance ?

    Thanks !

    1. Both pumps are almost identical. You can use them interchangeably and draw around 15 amps max.

  23. I have a aeromotive phantom 340 installed in my tank with a external relay. I am installing your 1200hp power adder do I leave my fuel pump wired like it is? Or should I bypass the relay and use the power wire from the fitech? And also I don’t need a external regulater at all??? Thanks in advance

    1. You can either bypass the relay or use the orange wire to trigger the relay. Both are acceptable.

  24. My current fuel pump circuit has a oil pressure safety shut off switch built in to it. Should I keep this circuit or does the EFI have a safety shut off built in to it?

    1. The EFI system has a similar feature that uses RPM as a reference. The moment when RPM is lost by the ECU it will immediately shut the fuel pump off.

  25. Hi, can you confirm if the Aeromotive Stealth 340 #11542 can be powered directly by the ecu?

    Aeromotive says the pump is compatible with PWM but will draw 15 amps at 60 psi.

    Thank you.


    1. This pump can be connected straight to the EFI but you need to contact Aeromotive to see if the pump can be pulse width modulated.

  26. hi i dont have any power on orange pump wire i have 12.50 volts red wire going to battery and 12.50 volts on white key wire when i check orange pump wire i only get 00.01 volts on meter

    1. The pump wire only has voltage for the first 5 seconds of key on, so you need to check the voltage with someone turning the key on for you to check this properly.