JMS Fuel Max Install

[96ss1664]

When I installed the JMS Fuel Max for my car I noticed that the JMS instructions were not vehicle specific and I hadn’t seen any threads here. So I thought I would try and do my first write up on this topic, hope this helps anyone looking to do this install.

JMS Fuel Max Install
1. Remove the driver’s seat by moving the seat all the way forward to remove the two T-50 Torx bolts, once you remove the bolts slide the seat forward and lift up on the seat to disengage it from the tracks. Unplug the main harness underneath the seat, and now you can remove the seat from the car.
2. Disconnect the battery Ground.
3. Find a suitable location to mount your JMS unit; I mounted mine next to the battery.

4. Remove the side access panel of the center console, start at the front working your way to the back. It’s held in by clips so be careful not to break them.
5. Now it’s time to run the plug in play accelerator activation cable, take the plug for the JMS unit and follow the same path the Red battery cable takes back to the battery.


6. Remove the back of the console to gain access while running the cable from the console to underneath the back seat. They’re two screws on both sides of the console that holds it on.

7. Pull up on the rear seat to gain access to run your cable, still following the Red battery cable


8. Now lean the back part of the seat down where you can see into the trunk, follow the battery cable into the trunk with your cable.

9. Plug the cable into the JMS unit.
10. Time to plug the accelerator harness in.

11. First, cut the terminals off the Black and Grey wires, tape each wire so they cannot make contact with one another or a vehicle ground and then zip-tie the wires to the harness where their out of the way.
12. Unplug the factory accelerator harness; plug the factory harness into the JMS harness. Now plug your JMS harness into the accelerator pedal.

13. Take the black 10 gauge wire from the JMS to the battery or vehicle ground.
14. Run the Red and White 10 Gauge wire from the JMS unit up to the fuse panel on the right side of the trunk, unplug fuse F12/FSCM. Instead of splicing into the factory harness I went with a GTC CT6100 fuse socket connector.



15. Plug the fuse socket into the F12/FSCM spot, use a volt meter to determine which terminal has a constant +12 Volts. Connect the Red JMS wire to the constant 12 volts terminal.
16. Connect the White JMS wire to the other terminal which has no voltage on it.
17. Connect battery ground.
18. Follow the JMS instructions on how to program and setup the JMS Fuel Max.

Here is a diagram if you want to splice in the JMS. Found this on a CTS-V forum.


Here is a diagram if you want to use the Fuse Socket.

[Rando73]

Awesome write up!

[collins8]

Nice write up. I have read that the ZL1 does not like a voltage booster used with its fuel pump control loop. I have read the fuel pump control module will end up throwing codes and in the end it does not work well. Worst case there is a chance the fuel pump control module could go into a thermal over load condition and shutdown on you and that would really suck going lean and ruining an engine. I talked to James Short a very reputable tuner about using one and he told me he does not like them and they just cause problems. I have also talked to Carl at vaporworx
https://www.vaporworx.com/documentat...-systems-work/
and he basically stated the same thing, the voltage boosters do not work well with the GM hardware to control the fuel system in these cars. Check out his site, there is some great reading there.
I am curious how the JMS unit works for you, and I would like for some of the tuners on this site to explain how the voltage boosters work for them. I would love to be able to add some ported heads to get a little more out of my car but I am at my fuel limit and I am not willing to risk the use of a voltage booster.
I know Carl at Vaporworx has been working on an upgraded GM Fuel pump control module that would work on these cars but I have not talked with him in some time to see how the project is going.

[blake-b]

Very nice write up! I have one in my SS but I am using a Hobbs switch to activate it and I am only boosting the second pump (Squash system).

[CarlC]

Agreed, nice write-up and documentation.

I too am interested in the programming used. Maximum voltage, ramp rate, etc. We have had good results using the JMS unit in both testing and multiple vehicle platforms.

Typically the GM FSCM's become unhappy at voltages reaching 16v+. This is where if it accepting a higher voltage the ramping function could be the reason.

[Bigtime53]

I must have been living under a rock because I have never heard of this. So if I have read this right you get more voltage to the fuel pump and it puts out more fuel? If that is the case it sounds like to me it would shorten the life of the pump because of heat or just plain wear it out sooner? Someone educate me please.

[ZO6 Bryan]

Originally Posted by Bigtime53

I must have been living under a rock because I have never heard of this. So if I have read this right you get more voltage to the fuel pump and it puts out more fuel? If that is the case it sounds like to me it would shorten the life of the pump because of heat or just plain wear it out sooner? Someone educate me please.

Actually more voltage makes the pump motor run cooler and much more efficiently. It is better for the pump. But to work with a E67 PCM that uses the FPCM it has to be wired correctly. You need to power the FPCM with the higher voltage, not just the pump.

Think of it this way. What is harder on your power window motor? Trying to raise the window with a drained down battery and the motor struggles to raise the window? Or putting the window up with a fully charged battery and the window raises quickly and smoothly?

Go here for more info. http://kennebell.net/KBWebsite/Commo...heory_kens.pdf

[ZO6 Bryan]

Originally Posted by collins8

Nice write up. I have read that the ZL1 does not like a voltage booster used with its fuel pump control loop. I have read the fuel pump control module will end up throwing codes and in the end it does not work well. Worst case there is a chance the fuel pump control module could go into a thermal over load condition and shutdown on you and that would really suck going lean and ruining an engine. I talked to James Short a very reputable tuner about using one and he told me he does not like them and they just cause problems. I have also talked to Carl at vaporworx
https://www.vaporworx.com/documentat...-systems-work/
and he basically stated the same thing, the voltage boosters do not work well with the GM hardware to control the fuel system in these cars. Check out his site, there is some great reading there.
I am curious how the JMS unit works for you, and I would like for some of the tuners on this site to explain how the voltage boosters work for them. I would love to be able to add some ported heads to get a little more out of my car but I am at my fuel limit and I am not willing to risk the use of a voltage booster.
I know Carl at Vaporworx has been working on an upgraded GM Fuel pump control module that would work on these cars but I have not talked with him in some time to see how the project is going.

Wrong!

[Rando73]

What settings are you guys running?

[Bigtime53]

Originally Posted by ZO6 Bryan

Actually more voltage makes the pump motor run cooler and much more efficiently. It is better for the pump. But to work with a E67 PCM that uses the FPCM it has to be wired correctly. You need to power the FPCM with the higher voltage, not just the pump.

Think of it this way. What is harder on your power window motor? Trying to raise the window with a drained down battery and the motor struggles to raise the window? Or putting the window up with a fully charged battery and the window raises quickly and smoothly?

Go here for more info. http://kennebell.net/KBWebsite/Commo...heory_kens.pdf

Bryan, so I am guessing here but FPCM means fuel pump control module so what is E67 PCM? But to answer my question this piece we are talking about does supply more fuel?

[ZO6 Bryan]

Originally Posted by Bigtime53

Bryan, so I am guessing here but FPCM means fuel pump control module so what is E67 PCM? But to answer my question this piece we are talking about does supply more fuel?

E67 is the computer used in the newer supercharged cars. I.e. CTS-V, ZR1 and the ZL1. For instance the Camaro SS has an E38 computer. And it controls fuel pressure differently than the non supercharged cars. And the Boost-a-pump does supply more fuel by giving the fuel pump more voltage that it needs to keep up with demand.
Like the example I gave on how your power windows behave when they don't have enough voltage to run properly.

[ZMEnow]

Originally Posted by ZO6 Bryan

E67 is the computer used in the newer supercharged cars. I.e. CTS-V, ZR1 and the ZL1. For instance the Camaro SS has an E38 computer. And it controls fuel pressure differently than the non supercharged cars. And the Boost-a-pump does supply more fuel by giving the fuel pump more voltage that it needs to keep up with demand.
Like the example I gave on how your power windows behave when they don't have enough voltage to run properly.

Thanks Brian for the write up as ths is in the JRE 75 - 125 kit that I will be putting on shortly.

[96ss1664]

Originally Posted by CarlC

Agreed, nice write-up and documentation.

I too am interested in the programming used. Maximum voltage, ramp rate, etc. We have had good results using the JMS unit in both testing and multiple vehicle platforms.

Typically the GM FSCM's become unhappy at voltages reaching 16v+. This is where if it accepting a higher voltage the ramping function could be the reason.

I will let you know my setup when my car gets tuned April 1, I have noticed that +16V to +16.5V is kind of the sweet spots. I'm going to start with the +0.8V Ramp and see how that works for my setup.

Originally Posted by DrkPhx

Nice write up. I like the fuse method. Nice and clean. I'm not sure about that diagram where it shows the red JMS wire (input) connecting directly to the battery. I thought about doing that so it has a constant voltage, so I called JMS and a few shops who use them and they said do not connect it directly to the battery. If you splice it, it should be into the red/white wire which goes directly to the FPCM.

So it would go:
red/white wire > red JMS wire [input to JMS unit] white JMS wire [ouput] > red/white wire > FPCM.

Also, one shop recommended installing it as close to the FPCM as possible (it's located on the rear passenger side sail panel) to minimize any voltage drop that may otherwise occur if you install it in the trunk. Which can happen because of the thin factory wire. I currently have mine installed in the trunk and was thinking of switching it, but I will first test for voltage drop using a digital multi meter to see if that happens.

Thanks, kind of curious why they don't recommend going to the battery. I know that it has constant voltage on the red/white wire all the time just like the battery. I do know they recommend only using the GM JMS unit because it has the feature of the JMS going into sleep mode and it wont drain your battery. You would have some voltage drop, but that can be overcome by adjusting the voltage output by the amount of voltage drop. Which I calculated it and it would be about .3-.4 Vdc.

[ABADZL1]

Originally Posted by Rando73

What settings are you guys running?

1.7v of throttle pedal for a linear ramp up max of 17.1v. This is my setting to maintain 65psi at wot.