[Archie123]

Hi,

I have a 2002 Focus LX which has developed an intermittent start problem.

The fault seems to be an electrical fault somewhere in the fuel system electrics.

Symptoms:
The car randomly will not start, after some investigation I found that the fuel pump is not firing so there is no fuel getting to the engine.
It happened about 3 months ago and I dropped the tank out, put it back together and off she went. Then last week it happened again, I dropped the tank, replaced the filter, checked that everything was ok, put it back together and off she went. Then, the day after it would not go in the morning but later in the day started fine. I drove it around for a few days and now it will not start again.

Attempted fixes:
I have dropped the fuel tank out twice, checked the pump, cleaned the tank, replaced the filter.
I have replaced the pump relay.
I removed the inertia switch and it seems to be fine (shorted the wires when I had the switch out and there was no improvement)

Can anyone suggest any other things to try?

Thanks

 

[autotec]

Well my friend, now it is time to pull a wiring diagram out. This is what I do half of my day now. Just start at square 1, are you losing the power or the ground? When you find that out, find out when the power ( or ground ) stops by checking the circuit as you move down the line. Take your time, and you can figure it out.

 

[sleepyboy]

Have you replaced the fuel pump itself? The older ones were faulty and ford made a "newer" one. If you never replaced the pump you should try that. ph and welcome to the forum [welcome] [ffrocks] [loveff] [wrenchin]

 

[whynotthinkwhynot]

Check the ground connections for the fuel pump which are under the rear seat if Australian Foci are built like US Foci. There should be 2 ground wires there connected to the chassis, and I'd also check or replace all chassis grounds at the battery for posterity's sake.

There is a fuel pump fuse, check your owner's manual for the location, but it should be ok. As far as I understand the system, the fuse and inertia switch are the only things that could stop the hot wires for fuel delivery. All other controls that could stop an engine are tied to the starter relay, not the fuel pump.

 

[Archie123]

Thanks for the responses, I will start off with the ground wires and report back.

I have been talking to Ford here and they are telling me that it is unlikely to be the pump or the engine management system.

It is diffucult to get a wiring diagram from Ford, does anyone have one for the fuel system? (fyi the plug is also under the back seat in Aus).

Really appreciate your help.

 

[Archie123]

Hi,

For future searches, the problem was the ground wires at the fuel pump plug. It looked as though it had been shorting as the hole in the hole in the plug had turned black.

Thanks for your help.