[CarlC]

Gents,

Justin and I have been trading emails back and forth, but here's a bit of recap of the tech side of this.

The factory FSCM can be challenging to adapt given the wiring involved. On a take-out everything MAY be there, but since it is designed for a 5th-gen there is stuff that needs to stay in the harnesses, and stuff that needs to go. For the sections that stay, they likely won't be the right lengths due to the differences in chassis designs. For the sections that don't need to stay, it becomes a wiring harness dissection and study course on what to eliminate.

For new parts, getting all of the right components can be challenging, and the same applies for adding/subtracting wire lengths, unneeded circuits, etc. By the time all is said and done, the VaporWorx controller, with a total of 4-6 control wires to connect, looks quite inviting. Cost -wise I have not checked on what a total GM FSCM would be.

As mentioned above, E38 can support FSCM or standard fuel system power. For standard systems, like that provided in Speartech's harness, a simple relay is used to provide fuel pump + power. VaporWorx uses this circuit to tell the PWM controller to turn on. In this scenario all of the OE safety features remain in place. The ECM fuel pump enable circuit, the same circuit used to trigger the relay in the Speartech harness, can be used to trigger the VaporWorx controller and have all safety features remain in place.

Also, the E38 should be re-programmed to have the FSCM turned off and the fuel pressure tables re-set to a constant 60 psi for the LSA. The associated FSCM wiring and computer can also be removed. A manifold referenced fuel pressure can be used but we have found that a simple 60psi constant works well and is easier to install.