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Celebrating 250 Years of American Freedom, All Year Long! More Horsepower. More Burnouts.
Celebrating 250 Years of American Freedom. More Horsepower. More Burnouts.

Install Help


    

 FLEX FUEL PIN OUT GUIDE

Before You Begin-

Performance parts are fundamentally different from consumer electronics. They are often installed on highly modified vehicles where no two combinations are exactly alike. Vehicle year, trim level, existing modifications, calibration, aftermarket components, and previous repairs can all significantly affect installation procedures.

For that reason, many aftermarket performance products, including SMG products, do not include vehicle-specific, step-by-step installation instructions.

Where available, product-specific guides, wiring diagrams, pin-out information, or reference documents will be available for download directly from the product page. If a guide is not linked on the product page, one is not available for that product or application.

The information on this page is intended as a professional reference and assumes the installer:

  • Has experience with automotive electrical, fuel, brake, and mechanical systems.

  • Possesses the required specialty tools.

  • Understands safe installation practices.

  • Is capable of verifying proper operation before placing the vehicle into service.

Installation Support Policy

We are happy to provide support for:

  • Product compatibility and fitment

  • Missing or damaged components

  • Product identification

  • Clarification of information contained within our published documentation

Our support does not include:

  • Complete vehicle-specific installation walkthroughs

  • Step-by-step installation training

  • Custom wiring instructions

  • Custom fuel system design

  • Tuning or calibration assistance

  • Remote diagnostics of installation workmanship

  • Engineering or fabrication consultation

Many of the products we manufacture are intended for experienced installers and professional performance shops. Improper installation of fuel systems, electrical components, engine internals, suspension, or brake components can result in engine damage, fuel leaks, electrical failures, brake failure, property damage, serious injury, or death.

If you are not completely confident performing the installation safely and correctly, we strongly recommend having the product installed by a qualified professional.

Expert Services

Professional installation, custom fabrication, mechanical consulting, tuning, and calibration are professional services that are separate from the purchase of an SMG product.

Purchasing an SMG product does not include unlimited technical consulting, custom engineering, tuning advice, or step-by-step installation assistance.

Our technicians, tuners, and fabricators perform these services professionally every day, and those services require the time, experience, and expertise of qualified professionals.

Support Eligibility

Installation support is provided only for products purchased directly from SMG or through an authorized SMG dealer.

We cannot provide support for:

  • Used products

  • Second-hand purchases

  • Products obtained through unauthorized sellers

  • Modified or altered products

Tuning Requirements

SMG AUX Fuel Systems, BigBoy Pump Systems, and Flex Fuel Kits REQUIRE proper ECM/FSCM calibration before operation.

These products are not plug-and-play.

Failure to properly tune these systems can result in poor drivability, lean conditions, engine damage, or component failure.

SMG does not provide custom tuning advice or calibration support. Consult your qualified tuner before installing these products.

Flex Fuel Kit Notes

Current-generation Flex Fuel Kits feature our plug-and-play ignition coil jumper harness and no longer require fuse taps or dedicated ground wires.

Basic installation consists of:

  • Install the ethanol sensor at the fuel rail.

  • Connect the supplied ignition coil jumper harness.

  • Route the white signal wire to the PCM.

A weatherproof inline disconnect is included to simplify routing and PCM connection.

If PCM pin-out information is required, refer to our Universal PCM Pin-Out Guide AT LINK ABOVE.

Please note that not every year, model, or PCM strategy is covered. If your application is not listed, consult your tuner.

BigBoy Pump Notes

All BigBoy Pump Systems require tuning.

Baseline calibration information may be available on the applicable product page or included with the pump when appropriate. These values are intended only as a starting point for experienced tuners.

Important notes:

  • OEM fuel pressure regulators generally begin bypassing around 5 bar.

  • Excessive commanded pressure can reduce effective fuel delivery.

  • High-volume pumps do not require excessive fuel pressure; they require sufficient fuel volume.

  • Desired Pressure, Maximum Pressure, Duty Cycle, and FSCM tables should all be calibrated appropriately.

  • Avoid aggressive driving below 1/4 tank, particularly on saddle-tank vehicles where fuel transfer may not keep pace with demand.

AUX Fuel Kit Notes

Current AUX Fuel Systems utilize weatherproof connectors for the Hobbs switch, relay, and primary fuse.

The supplied Hobbs switch is factory preset and requires no adjustment.

Vehicle-specific mounting locations are intentionally left to the installer. Fuel line routing, wiring routing, pump placement, and tank fitting locations may vary depending on vehicle configuration and existing modifications.

Vacuum hose and a boost reference T-fitting are included.

For naturally aspirated applications, alternate activation methods such as RPM or window switches may be used; however, SMG does not provide installation or tuning support for those configurations.

General wiring reference:

  • Red ring terminal: Battery Positive

  • Black ring terminal: Chassis Ground

  • Fuse tap: Switched ignition source

  • Long power lead: AUX pump

Corvette kits utilize both positive and negative conductors within the rear harness.

Fuel connections:

  • Install the supplied NPT fitting in a location that maintains fuel pickup during acceleration.

  • Connect the supplied AN plumbing as required.

  • Tee into the factory feed using the supplied fitting.

Only use thread sealant on NPT threads.

Never apply sealant to AN fittings.

Do not overtighten AN fittings, as thread damage and fuel leaks may result.

15" Brake Conversion Notes

Brake system modifications affect vehicle safety.

The installer assumes all responsibility for verifying proper installation and safe operation before driving the vehicle.

SMG is not responsible for improper installation, reduced braking performance, wheel interference, or modifications performed during installation.

Additional notes:

  • Kits are designed around otherwise stock vehicle configurations.

  • Toe rods and bushings install only one direction. Verify all labels before installation.

  • Mixing components from other manufacturers may create fitment issues.

  • Some wheel combinations may contact the bleeder screws due to their shorter overall height compared to OEM.

  • Always perform a complete wheel clearance check before driving.

  • If calipers, brackets, or other brake components are modified for clearance, those modifications are performed entirely at the installer's own risk.

Replacement components are available from SMG when applicable.

Legacy Guides

Due to continuous product improvements, many older installation guides no longer accurately represent current products.

Current Flex Fuel Kits:

  • Mount underhood at the fuel rails (except frame-rail truck applications)

  • Utilize plug-and-play ignition coil jumper harnesses

  • No longer use fuse taps

  • Include a weatherproof PCM disconnect

Older guides should be used only for general reference and pin-out information where applicable.

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