Fuel tank located at the rear of the car under the seats removed to get to e36 fuel pump and fuel level sensor. Main system of tubes with the fuel goes under the bottom of the machine and consists of a tube direct feed (from the fuel pump in the gas tank to the rail with injectors) fuel filter (the latter is located directly under the driver's seat), tube return line (the valve on the rail with the injectors pits on the tube the excess fuel by controlling the pressure in the rail at the right level) and pipes of the ventilation system of the tank (venting vapor from the tank through the filter into the street. you can read here: the ventilation system of the fuel tank). The fourth tube, which is located next to the fuel tubes to the fuel system does not apply. It is brake fluid that goes to the rear wheels.
Under the hood is a rail with injectors and Fuel Pressure Regulator, and the adsorber (with the ventilation system of the tank) with your valve.
The principle of operation of the fuel system simple - pump constantly pumps the pressure in the rail (which you can check the pressure gauge on the rail). Fuel Pressure Regulator controls the constancy of the pressure in the system. If the pressure is normal, when you open the injectors the fuel is sprayed on the cylinder in accordance with its algorithm of opening/closing. If not normal then spraying may not occur when fuel will be poured into the cylinders and the car will not go.
As a rule, a malfunction of the fuel system bmw e36 m43 limited to malfunctions of the pump in the tank, leaks or pumped the fuel line (both direct and inverse), to the oppression of the injectors and idle Fuel Pressure Regulator. Examining all of these issues in turn you will most likely sort out the problems in the fuel supply. It should be understood that for proper operation of the engine meets multiple systems - fuel supply, air supply, cooling system, electronics, exhaust system and, in fact, the iron bar of the engine. Having achieved a stable pressure in the fuel system, and not eliminating the problem in the engine you have to deal with problems in other systems.
fault Diagnosis of the fuel system
First of all we need a pressure gauge to connect to the fuel rail, or just a gauge to connect directly to the fuel pump. Now you need to understand that the fuel pump in any case should provide more pressure than is written on the bleed valve of the fuel system. Read the pressure on the fuel valve and watch the pressure in the pump, it was no less. This can be done either directly connected to the pump, or by connecting a pressure gauge to the rail and pinching the return line near the engine. To run e36 fuel pump, you can either PowerNow key starter or link related contacts in the fuse box, or giving the power directly from the battery. If the pressure is less, the fuel pump cannot cope (it should also be measure with the lid of the tank and compare the result to check valve tank breather).
If the fuel pump and the ventilation system of the tank in order - check the rest of connecting the pump to the rail. Pinch the return line, start e36 fuel pump and observe the pressure. If it is less than indicated on the valve - problems with direct rail fuel - not sealed or clogged, a clogged filter, not sealed rail or poorly seated injector. All leaks with normal pump visible Nagas or the scent (smells like gasoline). The stiffness is checked by removing the fuel filter. Further conformed themselves.
If parizatoi the return line pressure is more than is written on the valve with a supply pressure is all right, and then there is a need to check the Fuel Pressure Regulator and return line. Usually, in 99% this is the Fuel Pressure Regulator, it may fail to open/close, or it may jam and it will permanently relieve all system pressure back into the tank. Ie if you pull the return line and observe the pressure on the rail less than indicated on the Fuel Pressure Regulator - Fuel Pressure Regulator replacement.