What Are The Symptoms Of A Failing Fuel Pump?

Question

Lately, whenever I try to start my car, the engine cranks a lot longer than usual, and is kind of rough starting up. Once it is going, though, the car runs just fine. (In case it matters, it's a 96 Mercedes E320). Is this evident of a failing fuel pump?

Answer 1

It is one of the things it could be, you need to do a pressure check to verify. But it could also be a fuel filter or fuel pressure regulator. All these can be diagnosed with a pressure test. There are several other things it could be but if your thinking its related to the fuel system then that's the first place to start checking.

Answer 2

check air filter and fuel filter.  Make sure the spark plugs are in good shape and not fouled.  Make sure you have good compression in each cylinder. and that all your spark plugs are getting the juice.

Answer 3

Have to also check to see if you are losing fuel pressure, within the entire fuel system, which have many components.

A fuel Gagepressure check at fuel pressure regulator, and see what the pressure is when started, and then have the vehicle sit to see the fuel pressure holds in the sealed system. A few lbs or bars loss has to be checked for allowable specs according to ther factory.

Many items in the fuel system can  be destroyed with foreign material. water, rust, and some time fuel additives, which destroy the factory rubber and electrical components within the fuel system.

Even not replacing the fuel filter on these systems can cause these metal particles to get into the fuel system Example: the burrs from the nozzle at the gas station.

Have a garage which this gage that it is a expensive tool to buy and can not be rented out at a parts store, and to be used by a qualified Tech.

Answer 4

it may be but you need a fuel pressure gauge installed so you can see if fuel pressure actually exists,try changing your filter may be restricted or add some kind of fuel injector cleaner to your fuel.

Answer 5

Could be.The only way to tell is check the pressure/flow .Does it hesitate on acceleration?