93 nissan sentra 1.6L crank but no start, replaced fuel pump, filter & relay, fuse ok, no engine light on instrument panel when key turned on but not start, also no fuel pump sound, disconnect connector to sending unit & checked with key on found no power going to fuel pump. any suggestions please would greatly help... Thank you...

Possible crank position sensor

Check for spark on any spark plug wire. If you have a strong blue spark, the ignition system is probably good, so then check for gas-is the fuel pump turning on for 2 seconds with key on, not start? It should and that will put gas up to the engine. If you don't hear the pump turn on briefly to pressurize the line and fuel rail (where the injectors are), you will need to troubleshoot the fuel pump circuit. Check the fuel pump fuse-probably under the hood in a fuse/relay block.

I assume you checked the fuel pressure and it is normal.
Are the spark plugs getting spark when it fails to start ?
Are you getting injector pulse from the computer ?
Any trouble codes stored in the computer ?

Could be any of several things. If the crank sensor is marginal and not sending pulses, the fuel pump is shut off. This is for safety. The pump is energized for a few seconds as key is turned in preparation for starting then engine must rotate normally to keep the pump on. If it stops, in a few seconds the fuel is cut off.

Hello, My name is Mike.

There is several things as you can imagine that could cause a car to not start if cranking. Good news is at least its cranking so that eliminates some things.

I try and have you test the most easiest cheapest thing first, then we go to plan B if that still does not work. Here is first what I want you to do.

If the car is run from cold for only a short period of time when you stop the engine the fuel pump continues to run on for a while. The pressure builds up and fuel leaks past the injectors into the cylinders. If the engine is warm enough it evaporates. If not it condenses over the spark plugs and when next you try to start it it is flooded and turning the starter just pumps more fuel in and makes matters worse.

Simple remedy is lift the hood and in the fuse box you'll find a fuse for fuel pump which should be removed. (check owners manual to locate if cant find)

Then crank the engine repeatedly with your foot to the floor just to pump lots of air through to dry things out.

Replace the fuse and start the engine.


NOW if this did not work with a couple of attempts from start to finish, then these are the things you need to check or possibly replace.

Again, I always try and look at the easiest for you first and well as cheapest, First check your plug wires, making sure no cracks and good connections. Then see if you can pull at least one plug, and inspect it, if it looks real black then it should be replaced, is misfiring. Check or replace Cap, and Rotor if carburetor, If fuel Injected, and always get a can of injector cleaner from auto Zone and they can even tell you were to hook it up on intake of injectors to clean injectors. Next would be checking your EGR and possible have to replace. But before that, I would replace Fuel filter as that is cheap and should be done regularly anyway.

Point is this, if you have good plugs, and wires, and EGR is good, and fuel filter is good, then it should start. I think the first method at top might solve it, but PLEASE first find your fuel pump relay to make sure your getting fuel. You can test this if getting fuel or not, by getting some starter fluid and spraying into intake area, as you crank it, if it cranks then it is not getting fuel, then could be fuel pump relay, fuel pump, or even a vacuum leak. When you turn on car (not start) listen with head out door to see if you can hear fuel pump coming on, should be like a buzzing type or Humming sound. That will also confirm your fuel pump is working. Then if it cranks, and wont start, then were back to fuel filter, fuel relay fuse, or vacuum leak, or like i said EGR. Please keep me informed. Thanks Mike

install a fuel pump guage and check pressure at key on and start, it should hardly vary, it the pressure is constant check the injector signal with a noid light, while you are at it check spark(no spark no injector signal) you won't find a relay fuse

The used ECM needs reprogrammed for your vehicle.

FUEL PUMP RELAY SHOULD BE IN THE ENGINE COMPARTMENT.BUT I HAVE KNOWN FUSE PUMP FUSE AND RELAY BE IN THE INTERIOR FUSE BOX UNDER THE LEFT SIDE OF THE INSTRUMENT PANEL ON THE DRIVER SIDE.

ur fuel pump is inside ur fuel tank underneath the back seat/ fuel filter is inside the engine compartment near the intake manifold

I know this sounds ridiculous, but if you just bought this car with it not running and you have never owned a 5-speed, push the clutch in to start it. On most cars, the list and location of relays are on the inside of the fuse/relay cover. If it's not labled inside the covers, the dealers will often times print out a diagram for free.