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[terry paget]

X84GNB 2000 2.5 petrol manual estate
Engine cranks well but does not start. My first thought was failed crank sensor. Then I loosened a fuel pipe to check fuel feed when cranking, and found there was none. There is fuel in the tank.

I know there is a relay, but do  not know where. Is there a fuse? Perhaps the pump has failed.

Please advise procedure to isolate fault.

[The Red Baron]

fuse 18, 20amp. in dash. 

[05omegav6]

Give the tank a kick from under the bumper whilst a willing assistant cranks it

Pumps stick when they start to fail...

Other thing is to swap the two purple relays in the engine bay fuse box with ones from a working car

[albitz]

Iirc the fuel pump wont pump fuel if the crank sensor has died.

[05omegav6]

Iirc the fuel pump wont pump fuel if the crank sensor has died.

It runs briefly at position 2 to prime the fuel rail. If the engine fires, then it starts and runs permanently...

[terry paget]

Thanks Gentlemen. I have checked Fuse 18, it's OK. I have pulled out the two purple relays, but could not get both purple relays out of R706FHD, a 2.0 petrol. I got one out, I have more at work so will bring them home tomorrow.

[symes]

dont know if important or not but check the terminals are the same on the relays you exchange---my miggy had 1 more pin on its relay than on the relay i got from another miggy---wierd

[terry paget]

Iirc the fuel pump wont pump fuel if the crank sensor has died.

It runs briefly at position 2 to prime the fuel rail. If the engine fires, then it starts and runs permanently...

I always believed the fuel pump operated at low rpm as long as the starter was cranking, but not with just the ignition switched. This presumably was a safety measure to avoid fuel fires after accidents. I did expect fuel to feed while I cranked the starter. It did not happen.

[Webby the Bear]

Iirc the fuel pump wont pump fuel if the crank sensor has died.

It runs briefly at position 2 to prime the fuel rail. If the engine fires, then it starts and runs permanently...

Could this be linked to crank sensor.... in college we observed a mondeo that had a faulty crank sensor. we checked for spark during cranking and there was no spark. this is apparently indicative of a failed crank sensor. if it has no spark is something somewhere cutting the fuel off as precaution??? just a thought

[terry paget]

Iirc the fuel pump wont pump fuel if the crank sensor has died.

It runs briefly at position 2 to prime the fuel rail. If the engine fires, then it starts and runs permanently...

Could this be linked to crank sensor.... in college we observed a mondeo that had a faulty crank sensor. we checked for spark during cranking and there was no spark. this is apparently indicative of a failed crank sensor. if it has no spark is something somewhere cutting the fuel off as precaution??? just a thought

As said above, I see the wisdom of cutting off fuel supply below, say, 200rpm, to minimise fire risk. But engine will never start unless fuel pressure is raised while cranking to start engine, therefore pump relay is engaged with starter relay.

Today I shall substitute good violet relays for the two in X84GNB. IF no change, I suppose i should next check volts and action at the fuel pump.

I have had five non starter Omegas, all caused by failed crank sensors. I did not note down that I had checked fuel feed on those occasions, but I think I would have.

Does anyone know which colour wires to fuel pump and gauge socket are power to the pump?

[philhoward]

I think pump feed is blue/red (or is it red/blue)?

[philhoward]

..and I don't recall a priming pulse either (had fun trying to get my X30XE running from empty and a dead crank sensor); manually jumpered the fuel pump relay to get fuel up to the rail.

[05omegav6]

If no joy with the relays, give the tank a kick about a foot in from the towing eye whilst some one else cranks it

If it fires, the pump is on its way out...

Quicker and easier than testing for a wiring fault... might as well start with the easy stuff

[Marks DTM Calib]

In all the years I have worked on them, I have never seen a priming pulse on the 2.5/3.0, the fuel relay only pulls in when the crank shaft is seen to turn.

Reality is that the fuel pressure remains for days and even weeks after the engine is turned off (unless you have a leaky injector) so no need for it.

Hence crank sensor is a favourite.

An option is to pop the top off the fuel pump relay and manualy actuate the relay if you must, do you have a spark?

[philhoward]

Reality is that the fuel pressure remains for days and even weeks after the engine is turned off (unless you have a leaky injector) so no need for it.

In my case I'm not using the Omega pump (or tank) - one from a Ford Focus of unknown heritage and I think Fords DO have a priming pulse..perhaps as their pump setup isn't as good?

Not helping the OP's problem though