Hi Biker. Let's take a deep breath and start again.
You said that you ran a cable from the battery to the fuel pump,
heard a noise in the engine bay, and assumed your pump was running.
The fuel pump is mounted in the top of your fuel tank. Access is through
a circular panel in your boot floor.
Are you saying that you ran the cable all the way to the back of the car,
through the boot access panel, disconnected the pump plug, connected to
the pump +ve terminal, and rigged up a separate earth return?
If you didn't, then you haven't checked your pump is running.
You also said that you disconnected the fuel lines and there was no fuel
pressure. Seeing as you would have done this after your car failed to start,
it's a fair assumption that you exhausted any pressure and the pump
failed to run and re-pressurise your fuel system.
This means that either:
1)Your ECU is not energising the fuel relay. Either because of no signal from
your Crank Sensor, an open circuit in the relay energising circuit, or a faulty
relay.
2)A fault in the pump circuit that the relay energises. This could be the +ve
feed or the earth return.
3)A faulty pump.
4)Your fuel guage is knackered and you haven't got any fuel in the tank.
(Don't laugh. You wouldn't be the first to have this)
Do you have a multimeter or a test bulb that you can check your circuits with?
If you haven't you can't go much further until you do.
You need to check all your circuits. Remember that the relay and the pump
circuit will only work for a few seconds when you switch on the ignition to pressurise
your fuel system for starting. When you crank the engine over, the circuit
will only energise again if the ECU receives a correct signal from the Crank
Sensor.
Bearing this in mind, that you'll only have a short time window to check for a feed,
check that you're getting a feed to the pump fuse. If not you need to check the
continuity of the circuit between the fuse and the Relay. If ok, you need to check if the Relay
is operating. Check the continuity between the ECU and the Relay operating circuit.
If OK, then check out the Relay by taking it out and rigging a circuit to provide a
positive feed and Earth return to the Relay operating circuit, listen for it it click, and
check for continuity in the main circuit that it makes when it operates.
If OK, replace your Crank Sensor.
If there is a +ve supply to the pump fuse, then you have a problem with either
the circuit to the pump, that includes the +ve feed and the Earth return, or a
faulty pump. Disconnect the plug from your pump and check you are getting
12V to the pump. If not you have a wiring fault between the Fuse and the Pump.
If OK, check the continuity of your Earth return from the Pump. If faulty check
the cabling and repair the fault when found.
If everything OK, then you are looking at a faulty pump. But before condemning it,
rig up an independent +ve feed and Earth return to the Pump from a battery
and check that it actually doesn't run, just in case you've made a mistake in your
other checks. You don't want the cost of replacing a pump unless you are certain.
Post up your results as you run through the checks, or anything you are unsure of,
and electrical experts on here will give you an answer or an opinion.
Just work through everything logically, eliminating possible faults one by one.
Do NOT just go and buy a spare on spec. You'll rapidly empty your wallet to
no effect.
Good luck!
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Topic: wont start (Read 3071 times)