[JaxSS]

I just installed the JMS boost a pump and it’s not activating when the throttle is depressed light just stays steady all dip switches are correctly set 5(off) 4(on) 3(on) 2(off) and 1 off after configuration. When I touch the grey and black wire together by the pedal harness it’s activating the boost a pump (light blinks) but for some reason depressing the pedal will not activate the unit no matter what I do. Im pretty sure its configured correctly but any assistance would be greatly appreciated.

[TJay74]

I just installed mine as well.

There should be a harness that went up front to the throttle pedal. Then there is a jumper harness that plugs into the throttle pedal assembly, it has a small black single pin connector that comes off of it. Basically it intercepts the throttle pedal signal and then sends it back down the single black connector to the JMS. Make sure you plug that into the harness that has the 2 loose wires with the ring terminals on it.

Also make sure to check the JMS switches out closely, they are super hard to read even with a light shinning on them.

[JaxSS]

I have the jumper harness to the pedal all plugged in and the single connector off the harness is plugged into the red wire with the matching connector coming from the boost a pump. The directions I have say the black and grey wire are only used to configure the unit and should be separated and taped up once setup. I checked out the whole harness to make sure the wiring was ok everything seems fine but the boost a pump doesn’t seem to be getting signal from the pedal. ����*♂️

[TMS]

Did you set the baseline voltage and then follow up by setting the ramp in voltage?

[TJay74]

Originally Posted by TMS

Did you set the baseline voltage and then follow up by setting the ramp in voltage?

On the JMS box there are 2 rotary pots on the side, they are red in color. One is the 50% adjust (The point where the throttle has to go over before the JMS will boost the voltage).

The other pot is the 100% adjustment, it adjusts how much output voltage the JMS pushes once the pedal reaches the 50% trigger point.

[TMS]

Perhaps you’ll find this helpful.

You need to calibrate both the input trigger and the output voltage on your car.

Below are my instructions on how to do this. Since you are using the accelerator pedal you need to configure the unit to ramp in using 0-5v sensor (accelerator pedal is the sensor) and not a time ramp. Thus switch #3 must be set to on. Further, you want to set switch #4 to on and #5 off so it configures the unit for a 0.4V increment which is the smallest increment. This will give the most granularity of the ramp in using the accelerator pedal. If this incremental voltage is set too high based on the dipswitch combinations of 4 and 5, then when the voltage starts ramping up it might go from 14.4v Base to 17.47V starting at 50% throttle and maxing out early at 60% throttle. We want to spread the ramp-in over the largest percentage of pedal movement possible (something like ramp in at 50% throttle and maxes out around 80% throttle).

Steps for configuration:

Note: it really helps to have a second person when it comes to setting the ramp-in trigger using the accelerator pedal.

1) You'll test voltage on the white wire of the JMS booster (I used a sharp voltmeter probe to pierce the wire insulation).
2) On the dip switches - 1 is on (program settings mode), 2 is off, 3 is on, 4 is on, 5 is off.
3) Output Voltage Set - Two ground wires coming out of the JMS Pedal harness near the accelerator (gray and black) get touched together with car running. Turn the dial knob on the JMS unit labeled "adjust output voltage" until you get as close to 17.47V as you can on the voltmeter. At this point, you have set the output max voltage. Turn dip switch 1 off to save the programming changes (before you kill power). Now, disconnect the two ground wires (gray & black) from each other and tape each of them up so they don't accidentally ground out. These stay unconnected. Shut ignition off.

4) Input voltage ramp-in trigger - This is where a 2nd person comes in handy. Turn the ignition on with engine off. Turn Dip switch 1 on to go into programming mode. With HPTuners VCMScanner connected (or whatever tuner you are using), monitor the "Accelerator Pedal Position" channel. Push accelerator pedal down until you reach as close to 50% on this channel (pedal should be about half way down). Now while one of you is holding the pedal steady at 50% have the second set of hands turn the "Adjust Input Trigger" dial on the JMS unit up or down until the base voltage of 14.4V begins to just start ramping up. Once that dial is set, test your ramp-in to make sure everything works properly. Simply let off of the accelerator pedal. Have your partner watch the voltmeter. It should stay steady at about 14.4V. then slowly press the pedal down until you get to 50%. 0%-50% throttle should stay at 14.4V. Once you go above 50%, the voltmeter should start registering an increase in voltage. Have your helper call out the voltage while you keep pressing the pedal down. Your partner should see the voltage climb up to and max out at 17.47v or so (whatever the max voltage ended up being on the previous step). It will likely max out somewhere between 75% and 80% throttle position which is perfect. Then, as one final test, just mash the pedal to the floor and make sure the voltage goes to 17.47v. Now make sure you turn dipswitch 1 off to save your settings (before you kill the ignition).

You're Done!

Hope this helps.

Trevor

[TJay74]

Trevor thanks for the info, that will come in handy for me tomorrow as I go back thru the settings on mine. I got the wiring corrected today, now I need to check the settings again.

[JaxSS]

Thank you Trevor finally got it figured out ����

[nezoid]

After everything is configured as listed above, does messing with the dials change the configuration? Or would you have to go through the process again?

[TMS]

Originally Posted by nezoid

After everything is configured as listed above, does messing with the dials change the configuration? Or would you have to go through the process again?

The only time the pot dials should affect the calibration is when the box is in program mode which is when dip switch #1 is on. Once you are finished with the configuration and exit programming mode, I believe it disables the pots.

[travislambert]

How was the 17.47 derived? Is this a limit based on current draw, pump rating, cavitation threshold, FPCM limit...

I'm trying to figure out the max voltage I can run without issues on my ZL1. This is a track car and it's currently running out of fuel below a half tank of gas, after a hard right turn followed by a long straight (due to the saddle tank). I guess the jet pump on the left side just can't feed enough on its own. Otherwise it's fine.

[parish8]

Originally Posted by travislambert

How was the 17.47 derived? Is this a limit based on current draw, pump rating, cavitation threshold, FPCM limit...

I'm trying to figure out the max voltage I can run without issues on my ZL1. This is a track car and it's currently running out of fuel below a half tank of gas, after a hard right turn followed by a long straight (due to the saddle tank). I guess the jet pump on the left side just can't feed enough on its own. Otherwise it's fine.

I cant answer your question but how is a boost a pump going to help with your issue?

[travislambert]

Originally Posted by parish8

I cant answer your question but how is a boost a pump going to help with your issue?

Because if the pump can move more fuel it'll work just like any Camaro when the fuel is only in the left side of the tank. In our cars, if you have less than 1/2 tank of fuel and take a hard right turn, ALL of the fuel will migrate to the left side of the tank. The right side is completely empty, but the way the pump is designed to pull from both sides, it works just fine.

The problem is when you add more fuel demand (with a 2650 in my case), the pump struggles to keep up when fuel is only in the left side of the tank (opposite the pump). Once the fuel bucket on the pump is empty, pressure drops quickly.

I turned my booster to 17.445 volts and I've been running all day so far at VIR without issue. Of course, I've purposely been keeping more fuel in the tank, but I do have data showing fuel only in the left side while running about 155+ MPH without a pressure drop.

[Joshinator99]

Originally Posted by TMS

Perhaps you’ll find this helpful.

You need to calibrate both the input trigger and the output voltage on your car.

Below are my instructions on how to do this. Since you are using the accelerator pedal you need to configure the unit to ramp in using 0-5v sensor (accelerator pedal is the sensor) and not a time ramp. Thus switch #3 must be set to on. Further, you want to set switch #4 to on and #5 off so it configures the unit for a 0.4V increment which is the smallest increment. This will give the most granularity of the ramp in using the accelerator pedal. If this incremental voltage is set too high based on the dipswitch combinations of 4 and 5, then when the voltage starts ramping up it might go from 14.4v Base to 17.47V starting at 50% throttle and maxing out early at 60% throttle. We want to spread the ramp-in over the largest percentage of pedal movement possible (something like ramp in at 50% throttle and maxes out around 80% throttle).

Steps for configuration:

Note: it really helps to have a second person when it comes to setting the ramp-in trigger using the accelerator pedal.

1) You'll test voltage on the white wire of the JMS booster (I used a sharp voltmeter probe to pierce the wire insulation).
2) On the dip switches - 1 is on (program settings mode), 2 is off, 3 is on, 4 is on, 5 is off.
3) Output Voltage Set - Two ground wires coming out of the JMS Pedal harness near the accelerator (gray and black) get touched together with car running. Turn the dial knob on the JMS unit labeled "adjust output voltage" until you get as close to 17.47V as you can on the voltmeter. At this point, you have set the output max voltage. Turn dip switch 1 off to save the programming changes (before you kill power). Now, disconnect the two ground wires (gray & black) from each other and tape each of them up so they don't accidentally ground out. These stay unconnected. Shut ignition off.

4) Input voltage ramp-in trigger - This is where a 2nd person comes in handy. Turn the ignition on with engine off. Turn Dip switch 1 on to go into programming mode. With HPTuners VCMScanner connected (or whatever tuner you are using), monitor the "Accelerator Pedal Position" channel. Push accelerator pedal down until you reach as close to 50% on this channel (pedal should be about half way down). Now while one of you is holding the pedal steady at 50% have the second set of hands turn the "Adjust Input Trigger" dial on the JMS unit up or down until the base voltage of 14.4V begins to just start ramping up. Once that dial is set, test your ramp-in to make sure everything works properly. Simply let off of the accelerator pedal. Have your partner watch the voltmeter. It should stay steady at about 14.4V. then slowly press the pedal down until you get to 50%. 0%-50% throttle should stay at 14.4V. Once you go above 50%, the voltmeter should start registering an increase in voltage. Have your helper call out the voltage while you keep pressing the pedal down. Your partner should see the voltage climb up to and max out at 17.47v or so (whatever the max voltage ended up being on the previous step). It will likely max out somewhere between 75% and 80% throttle position which is perfect. Then, as one final test, just mash the pedal to the floor and make sure the voltage goes to 17.47v. Now make sure you turn dipswitch 1 off to save your settings (before you kill the ignition).

You're Done!

Hope this helps.

Trevor

This was post was very helpful! Thanks to @TMS!