Fuel Supply Component Description. Cadillac Catera 1999

For 1990-2009 cars only

Makes 🢒 Cadillac 🢒 1999 🢒 Catera 🢒 Engine 🢒 Engine Controls - 3.0L 🢒 Fuel Supply Component Description

Fuel Tank

The fuel storage tank is made of high density polyethylene and is located behind the rear wheels. The fuel storage tank is held in place by two metal straps that are attached to the under body of the vehicle. The tank shape includes a sump in order to maintain a constant supply of fuel around the fuel pump strainer during low fuel conditions or during aggressive maneuvers.

The tank also contains a fuel vapor vent valve with a roll-over protection. The vent valve also features a two phase vent calibration which increases the fuel vapor flow to the canister when the operating temperatures increase the tank pressure beyond an established threshold.

On-Board Refueling Vapor Recovery (ORVR) System

The on-board refueling vapor recovery (ORVR) system is an on-board vehicle system to recover fuel vapors during the vehicle refueling operation. The flow of liquid fuel down to the fuel tank filler neck provides a liquid seal. The purpose of ORVR is to prevent refueling vapor from exiting the fuel tank filler neck. The ORVR components are listed below, with a brief description of their operation:

•	The Fuel Tank--The fuel tank contains the modular fuel sender, the fuel limiter vent valve, and 3 rollover valves.

•	The Fuel Filler Pipe--The fuel filler pipe carries fuel from the fuel nozzle to the fuel tank.

•	The EVAP Canister--The EVAP canister receives refueling vapor from the fuel system, stores the vapor, and releases the vapor to the engine upon demand.

•	The Vapor Lines--The vapor lines transport fuel vapor from the tank assembly to the EVAP canister.

•	The Check Valve--The check valve limits fuel spit-back from the fuel tank during the refueling operation by allowing fuel flow only into the fuel tank. The check valve is located at the bottom of the fuel filler pipe.

•	The Modular Fuel Sender Assembly--The modular fuel sender assembly pumps fuel to the engine from the fuel tank. The fuel tank pressure sensor is located on the modular fuel sender cover.

•	The Fuel Limiter Vent Valve (FLVV)--The FLVV acts as a shut-off valve. The FLVV is located in the fuel tank. This valve has the following functions:

-	Controlling the fuel tank fill level by closing the primary vent from the fuel tank

-	Preventing fuel from exiting the fuel tank via the vapor line to the canister

-	Providing fuel spillage protection in the event of a vehicle rollover by closing the vapor path from the tank to the EVAP canister

•	The Pressure Vacuum Relief Valve--The pressure vacuum relief valve provides venting of excessive fuel tank pressure and vacuum. The valve is located in the fuel filler neck on a plastic fuel tank.

•	The Vapor Recirculation Line--The vapor recirculation line is used to transport vapor from the fuel tank to the top of the fill pipe during refueling to reduce vapor loading to the enhanced EVAP canister.

•	The Variable Orifice Valve--The variable orifice valve regulates the amount of vapor allowed to enter the vapor recirculation line.

Fuel Tank Filler Pipe

In order to help prevent any refueling with leaded fuel, the fuel filler pipe has a built-in restrictor and a deflector. The opening in the restrictor will accept only the smaller unleaded gasoline fuel nozzle which must be fully inserted in order to bypass the deflector. The filler pipe is attached to the tank by a section of hose and two hose clamps. The tank is vented during filling by an internal vent tube inside of the filler pipe.

Fuel Filler Cap


(1)	Fuel Tank Filler Cap
(2)	Fuel Tank Filler Pipe
(3)	Fuel Filler Door

Notice: Use a fuel tank filler pipe cap with the same features as the original when a replacement is necessary. Failure to use the correct fuel tank filler pipe cap can result in a serious malfunction of the fuel system.

The fuel tank filler pipe is equipped with a turn to vent screw on the type cap which incorporates a ratchet action in order to prevent over-tightening.

The turn to vent feature allows the fuel tank pressure relief prior to removal. Instructions for proper use are imprinted on the cap cover. A vacuum safety relief valve is incorporated into this cap.

Modular Fuel Sender


(1)	The Fuel Pump
(2)	The Fuel Gauge Float Arm
(3)	The Fuel Reservoir

The modular fuel sender assembly mounts to the threaded opening of the plastic fuel tank with a multi-lipped seal and a threaded retainer (nut). The reservoir, containing the exterior inlet strainer, the electric fuel pump and the pump strainer, maintains contact with the tank bottom. This design provides:

•	Optimum fuel level in the integral fuel reservoir during all fuel tank levels and during driving conditions

•	An improved tank fuel level measuring accuracy

•	An improved coarse straining and added pump inlet filtering

•	More extensive internal fuel pump isolation for noiseless operation

The modular fuel sender assembly maintains an optimum fuel level in the reservoir (bucket). The fuel entering the reservoir is drawn in by the following components:

•	The first stage of the fuel pump through the external strainer

and/or

•	The secondary umbrella valve

•	The return fuel line, whenever the level of fuel is below the top of the reservoir

Fuel Pump

The electric fuel pump is a turbine pump which is located inside of the modular fuel sender. The electric fuel pump operation is controlled by the ECM through the fuel pump relay.

Fuel Sender Strainers

The strainers act as a coarse filter to perform the following functions:

•	Filter contaminants

•	Separate water from fuel

•	Provide a wicking action that helps draw fuel into the fuel pump

Fuel stoppage at the strainer indicates that the fuel tank contains an abnormal amount of sediment or water. Therefore, the fuel tank will need to be removed and cleaned, and the filter strainer should be replaced. Refer to Fuel System Cleaning.

In-Line Fuel Filter

A steel in-line filter is used in the fuel feed line near the fuel tank. The filter element is made of paper, and is designed to trap particles in the fuel that may damage the injection system.

EVAP Lines and Hoses

The EVAP line extends from the fuel tank vent valve to the EVAP canister and into the engine compartment. The EVAP line is made of nylon and connects to the EVAP canister with a fuel resistant rubber hose and quick connect fittings.

Fuel Pressure Regulator

The fuel pressure regulator is a diaphragm operated relief valve. The fuel pump pressure is on one side of the regulator, and the regulator spring pressure and the intake manifold vacuum are on the other side. The function of the fuel pressure regulator is to maintain approximately 350 kPa across the director spray plate under all of the operating conditions. The pressure regulator compensates for the engine load by increasing the fuel pressure as the engine intake manifold vacuum drops. The pressure regulator is mounted on the fuel rail.

With the engine running at idle, the system fuel pressure at the pressure test connection should be between 275-313 kPa (40-46 psi). If the pressure regulator supplies a fuel pressure which is too low or too high, a driveability condition will result.

Fuel Rail


(1)	The Fuel Rail
(2)	The Fuel Supply Line
(3)	The Fuel Return Line
(4)	The Fuel Pressure Regulator

The fuel rail consists of four parts:

•	The pipe that carries fuel to each injector

•	The fuel pressure regulator

•	The fuel pressure test port

•	Six individual fuel injectors

The fuel rail is mounted on the intake manifold and distributes the fuel to each cylinder through the individual injectors.

The fuel is delivered from the pump through the fuel feed line to the inlet port of the fuel rail pipe. From the fuel feed inlet, fuel is directed to the rail pipe to the fuel pressure regulator. Any fuel in excess of the injector needs flows back through the pressure regulator assembly to the outlet port of the fuel rail. The fuel then flows through the fuel return line to the fuel tank to begin the cycle again.

Fuel Injectors

The fuel injector is a solenoid device that is controlled by the ECM. When the ECM energizes the injector coil, a normally closed ball valve opens, allowing the fuel to flow past a director plate to the injector outlet. The director plate has holes that control the fuel flow, generating a dual conical spray pattern of finely atomized fuel at the injector outlet. The fuel from the outlet is directed at both of the intake valves, causing the fuel to become further vaporized before entering the combustion chamber.

The fuel injectors will cause various driveability conditions if the following conditions occur:

•	If the injectors will not open

•	If the injectors are stuck open

•	If the injectors are leaking

•	If the injectors have a low coil resistance

Throttle Body


(1)	O-Ring Seals

The throttle body contains a dual throttle valve which controls the amount of air that is being delivered to the engine. A coolant passage under the throttle valve heats the throttle body.

The Throttle Position (TP) sensor is mounted on the throttle body. The TP sensor and the minimum air stop are not adjustable.

Fuel Pump Relay

The fuel pump relay allows the ECM to energize the fuel pump. The ECM enables the fuel pump whenever the CKP sensor pulses are detected.

Engine Control Module (ECM), Inputs/Sensors

The ECM receives the data from various information sensors and other inputs. For detailed information on the ECM, the sensors and the other inputs, refer to Engine Controls, Engine Control Module (ECM), Inputs/Sensors.