bloody plastic cars

[welshmike]

OK guys, i need your help/advice. I know its not Old Skool, if it was id likely have it sorted by now! but..

 

My sister has a Mk3 Mondeo 1.8 Duratec, one day last week it wouldnt start, cranking over fine but no sign of life whatsoever. Later the same day it started and ran fine, without touching anything at all.

 

Then the other day the problem came back, i had a look at it and worked out it wasnt getting any fuel to the engine. Lifted the back seat to access the fuel pump and couldnt hear it pumping at all, unplugged the electrical connector to test for power with a multimeter and it showed over 12v. Fuel pump must be buggered i thought, ordered a new one, just fitted it but it still doesnt pump.

 

I put power straight to the pump from a seperate battery to check it wasnt a dud pump and it pumps fine, still getting over 12v at the cars wiring to the pump but when i connect it, nothing. Thought it must be a problem within the plug itself so carefully took each pin out of the plug and connected them to the pump to eliminate any loose connections, but still no life in the pump. The engine still turns over fine but doesnt even sound like catching.

 

With the electrical plug dismantled i could test the voltage while it was connected to the pump, and it showed nothing at all. So, what ive figured out is, with the ignition on, unplugged there is 12v, as soon as you plug it in that drops to zero?!

 

what could cause this? some sort of ECU / Fuel Module problem? My electrical knowledge is fairly limited so it could be something dead simple. next step i think is go through the fuses for ecu / control modules but i cant be arsed now, im freezing cold and soaking wet and had enough of this plastic piece of poo.

 

So does anyone have any suggestions? is there a common fault with these? I know theres some clever people on here, thanks in advance.

[Escort Mk1 4 Door]

dont think he have had that yet ill check when im at work today, i know we have had the flaps in the inlet go and they are a bugger on the 2.0 not sure about 1.8 if it has them

[katana]

Most ECU's provide a switched earth to the fuel pump relay so although you may have 12v to chassis if the earth circuit is screwed somewhere - no start. As it seems intermittent i'd try relay first? 

[john_3.0s]

well if your certain the feed isnt present under load from the pump that suggests to me that the driver in the ECU has died but Its odd how it burst back into life then packed up again, if the ECU driver had failed i wouldnt expect to come back to life again like that.

 

Will the car run if you get the pump going with a direct feed to the pump i.e. bypassing the ECU? if so then at lest you can be sure its the pump ciccuit thats at fault somewhere. as Katana suggests see if its the +12v or the neg that dies when its under load.

 

Next up id be checking the voltage on the ECU connector to see if it behaves the same.

 

HTH

[welshmike]

Right, just got home from work, time to start again. 

 

Forgot to say last night, if i run the pump it starts fine so it is something in the fuel pump circuit.

A guy at work suggested it could be something to do with the imobiliser? but im doubtful

 

ill go out now and triple check the earth first as a few people have suggested that.

 

thanks for the replys any more thoughts would be hugely appreciated.

[john_3.0s]

thats a good start to have singled out the pump feed circuit as the problem.

 

it could be the imobiliser, that would explain why it started working again...

 

check the voltage on the pump when the key is in all positions, not just the aux on but also the running and start and see whats what.