As a retired BMW + MERCEDES tech, I can tell you the aftermarket pumps dont work well on our cars. do you have a Pick n Pull or like wrecking yard in your area? if you go to a self serve yard & look at the pumps on cars that use the same type of injection as your 318 (VOlVO, SAAB, AUDI, VW PORSCHE, MERCEDES) it is amazing the number of new or slightly used pumps you can find. just match up injection type, fitting size etc. The pressure/volume specs for bosch pumps really dont differ that much and the m42 being a small displacement 4 cyl is on the low volume side of the scale, so most others are higher volume anyway. A higher volume pump wont affect anything really because the injection only meters a timed pulse to the injectors which can only flow a preset amount based on pressure, any excess is rerouted back to the tank. As for noise, these pumps made noise when they were new, they got noisier when hot, when they get a little wear in them they do get louder though. Not sure which check valve your car is using, as there are at least 3 different versions of bosch pumps that were installed in m42's. Look at the outlet side of the pump there is probably a short fitting that screws into the pump and the lines attach to that if so pull it out and look at it, it will have a ball bearing and spring in it, that is the check valve, some pumps use a valve built into the pump but have a provision to add the screw in type. I have put many screw in valves in pumps that already had an internal 1, it wont hurt anything. back to Pick n Pull, a check valve out of almost any bosch pump will work if you have the afformentiond type. As to a fuel accumulator, it is merely a diaphragm and spring that takes out the fluctuations in fuel pressure and acts as a reservoir for fuel pressure, they rarely go bad in my experience. but if there is no working check valve to keep the pessure on the accumulator, the accumulator wont work.
hope this helps
Topic: Lots of cranking before starting....what could cause? (Read 5308 times)