Peripheral Components

Fuel System

The TPI Fuel System comprises the following components:

Fuel Pump

In the original GM applications, the fuel injection pressure pump is installed inside the vehicles fuel tank. Adapting this pump has never seemed to us a practical solution, unless you are installing the TPI system on a vehicle that utilises the stock GM gasoline tank. This would allow for the installation of an internal tank type pump. If you are installing the TPI system into a vehicle that was originally equipped with carburettors, or even a throttle body fuel injection system, it WILL be necessary to install a compatible high pressure port fuel-injection type pump. Any number of fuel pumps will serve the purpose. We can recommend the fuel pump from a 78-80 and 82-85 Datsun 280Z. The Nissan part number for this pump is 17011-P7211. In addition, these pumps are usually readily available from wrecking yards, as are similar units from BMW, Mercedes Benz, Jaguar and many other late-model port-injected vehicles.

The electric fuel pump used should be capable of maintaining at least 50 psi under full throttle, and a return line MUST be plumbed back to the fuel tank/tanks if there is not one installed on the car!

If the fuel tank in your vehicle does not have provision for a return line, it is NOT necessary to modify the tank!

By installing the appropriate size tee-fitting into the fuel supply line from the tank to the inlet side of the fuel pump and connecting the return line into this suction line at the newly installed tee, the need for a return line can be met without removing and modifying the fuel tank.

If you are installing your TPI system in a vehicle which was originally equipped with a carburetted engine and a mechanical fuel pump that was equipped with a factory installed return line, BE AWARE, that many of these systems have a restriction in the return line. This restriction should be removed to eliminate the possibility of unnecessarily high pressures in this portion of the fuel system. These restrictions are often contained in the return line fitting on the gas tank sending unit mounting flange. If it is inconvenient to access this flange to remove the restriction, the return line can be re-routed to the fuel pump inlet line, as described above.

Fuel Regulator

A fuel pressure regulator is mounted on the rear of the right side of the TPI fuel rail. This non-adjustable regulator controls fuel pressure, to maintain it at about 41 psi under high vacuum conditions, such as idle, and up to 47 psi under low vacuum conditions, such as full throttle operation. Adjustable fuel pressure regulators are available through a number of after-market suppliers, for high performance applications.

Fuel Lines

Because of the high fuel pressures involved, we prefer to use braided stainless fuel lines with threaded connectors, as opposed to just using hose clamps and rubber hose, when making the connection between the TPI unit and the fuel pump! The pressure inlet of the TPI system is the fitting with the larger I.D. A return line MUST be connected from the petrol tank to the smaller I.D. fitting. If you are utilising braided stainless hose and fittings, it will be necessary to purchase after-market adaptor fittings which thread into the hose connections, or the TPI manifold, to allow the use of these improved hose and fitting assemblies, since the OEM connections utilise metric threads and O-ring type seals. These adaptor fittings are available, either in a male configuration for installation into the fittings on the fuel rails of the TPI or, into the ends of the stock rubber hoses which attach to the body/frame mounted steel fuel lines that come forward from the fuel tank, or in a female configuration, for installation onto the end of the engine mounted steel tubing extensions, which are a part of all factory TPI fuel line installations.

The above-mentioned items are all that could be considered separate elements of which are component parts of the TPI installation. Simply stated, the system will not work at its designed level of performance if any one of the above items is deleted! The following information will include some additional items which, while not required to make the system functional, are items that are utilised in the factory installation to make everything work as originally designed, and which may be used, as necessary, or deleted if so desired, with no functional effect on the real world operation of the unit.

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