JMS BAP Installed Zero improvement, Any Ideas?
 

I recently installed a JMS BAP on my 2016 Camaro SS and I am not seeing any improvement in my lowside pressure. I have data logged the lowside presure, under a very streetable tune, whipple, lt4 fueling high pressure, injectors, intank, pump gas and 9 psi boost, lowside is reading 48 to 50psi of lowside pressure with or without jms connected. Trying to see if I am missing something or got something installed incorrectly.

I tapped into the red wire with the purple stripe that goes to the Chassis Control Module behind the rear drivers fender that feeds the fuel pump. (red wire from the JMS first into JMS then white wire from JMS out). I have it set up to be controled by the throttle, I have tested the voltage output on the white wire coming out of the JMS with the car turned off as someone push down on the throttle it increases from the battery voltage of 12.xx to 17.47 volts. I have also tested the voltage on the red wire with the purple stripe at the Chassis control module plug by connecting a voltage meter and setting it to max voltage reading and during a full throttle pull, it reads 17.47 max volts under a full throttle pull. I then tested the voltage on the grey wire that comes out of the Chassis control module plug that I believe feeds the intank fuel pump. The max voltage under a full throttle is right around 12.5 volts either with or without the JMS connected, I was expecting this to read around 14.5 volts without the JMS connected and 17.4 with the JMS connected. Has anyone tested the voltage on the grey wire that feeds the fuel pump?

Any ideas? Am I missing something? I am beginning to wonder if I got a bad ZL1 intank pump and need to switch it out.

Thanks for the input.

You might try reaching out to Jenetty...I'm at a loss on this one.

Hey Rob, I have this install on my car and can probably help. You can also reference Ted's instructions from his website, https://jannettyracing.com/pages/jms...er-gen-6-guide . Another good resource from this forum is https://www.camaro6.com/forums/showt...&highlight=jms . Let me know if I can help some more.

Thanks. It looks like I have it set up and configured similar to Ted's instructions.

Thing that has be stumped is I am seeing the voltage increase on the white wire coming out of the JMS as the throttle is press down but it is not resulting in any increase in fuel pressure. Did you ever test the voltage at the grey wire that goes to the in tank pump?

I will walk back through it all step by step to confirm I have everything setup correctly and let you know if I see any difference.

I went back through the configuration start to finish, no change. Everything checks out on the volt meter, with key on / car off volt meter starts at 12.xx until it reaches 50% throttle on hp tuners then builds to 17.48 volts. Confirmed volt output at white wire on full throttle pull, volt meter set to max volt read, shows 17.48 max volts after full throttle pull.

At this point either the increase in volts from the JMS is not getting passed on to in tank pump, as I am not seeing any increase in the volts at the grey wire that feeds the in tank pump, maybe this in normal? Or I got a bad ZL1 intank pump?

I feel like the intank pump is acting more like an LT1 intank pump, Has anyone connected a JMS to an LT1 in tank pump?

Hey Rob, do you have a Log that you could share? I also included the wiring diagram and pin connecter breakdown for the fuel pump. Wires 1 (+) and 2 (- or ground) at the pump should be your supply voltage for verification. You may need to adjust your "Fuel System Voltage Minimum" on your tune also.

The forum does not seem to allow logs to be uploaded. I upload a couple of screen shots from the logs, first one with the JMS and second without the JMS connected. I will send you a PM if you want to see the actual logs.

The wire I have been testing for voltage to the fuel pump is the grey wire that comes from the chasis control module to the fuel pump, wire #1 in your diagram. The wire shows as white in the original pictures I attached. Upper far right wire opposite end from the red wire with the purple tracer.

I had done some testing with the fuel system minimum voltage increased prior to buying the JMS, did not see much improvement. Haven't tried both together I will add that back into the tune to see if I notice any difference.

Thanks

Make sure you got the correct wire. Thee are no less than 5 wires in that harness bundle that are "red/purple" stripes. I ran into this problem myself since my FPCM is under the car due to my car being a 1LE.

Find the wire at the FPCM and pay very close attention to the color of the wire and how sharp and thick/thin the purple tracer stripe is, the correct one in my FPCM was a thin purple strip that had a very sharp and crisp edge where it met the red portion of the wire jacket.

My understanding from Ted is you wont see the voltage increase in the HPT Scanners program, you will notice it in the fact your LPFP readings will stay up and more consistent.

Make sure its wire 1 you tapped into on the plug going into the FPCM. Do you have a good ground connection?

The wire I tapped into is the red wire with the purple tracer, the wire that I have circled in green. This should be the #1 wire, let me know if you see it differently. I have logged voltage on this wire under full throttle by sticking the voltage meter probe into the back of the plug next to this wire and setting the volt meter to read max, it is reading 17.48.

The blue circled wire is the grey wire which should be #13 that goes to the fuel pump. I have tested the voltage on this wire also, in a similar manner, by sticking the voltage meter probe into the back of the plug next to the grey wire. This wire reads around 8 volts at idle and under full throttle reads 12.xx volts max. This reading is identical whether the JMS is plugged in or not.

I have not tested the green/blk wire #38 which is the low ref from the fuel pump.

I am using the same body ground that is in Ted's instructions.

Let me know if you see anything I am missing.

Thanks

Attachment 995444

possibly, it might be another story.

Just wondering when I use a BAP , do I need to tune FCM ? especially "Max Desired Pressure" in FCM tap?

Attachment 995445

It is also in "Fuel pressure" tap.

Do I need to adjust the both?

My max fuel pressure was update to 500kpa when I installed the zl1 intank pump. I dont show the fuel pump control tab, I must need to download an updated version of hp tuners to see it? I have version 4.4.4.

You need to read FPCM , then the tab will appear.
It will take 1 credit to flash your FPCM.

i would use the table from a SS 1LE car for that table.

Also you wont see the voltage increase in HPT, only at the actual wires at the rear. This is because the JMS catches the signal and increase it and then pushes the increase to the pump. The change never makes it thru the module is my understanding from talking with Ted.

The JMS directly increases the output voltage to the pump.