Mk4 petrol - fuel supply/pressure probs

[Shane the Painter]

I have just changed the fuel pump on my 2010 mk4 Mondeo 2.0l petrol. The previous pump had been identified as the problem with it failing to start. As the car has done 153k, I bought a used one from what I understand to be a reputable reclaimed spares dealer. All fitted correctly and the replacement was in very good condition when it arrived. Now the car will still not fire up. It falters after a few seconds and dies. On the faulty pump which has been replaced, it wouldn't even fire up enough for the engine to 'catch'.

Can anyone shed any light on this? Although the RAC guy ran diagnostics on it, no codes came up and he concurred that the issue all pointed to the pump. Is it possible that it could be a fuel pressure sensor instead? Or could it be a problem with the electronic throttle unit, making the management system 'think' there is no fuel supply?

The engine management light did NOT come on, either in connection with the 'dead' pump (removed) or now with the replacement pump.

Any ideas anyone...????? 

[dezwez]

do they have a fuel filter on them

[Shane the Painter]

2 minutes ago, dezwez said:

do they have a fuel filter on them

I've no idea I'm afraid. I know the diesels do. Not sure about the petrols.

[dezwez]

best to check on the older focus it under the car near the fuel tank i don't no about the mondeo i had one so bad it wouldnt let fuel though

[Shane the Painter]

14 hours ago, dezwez said:

best to check on the older focus it under the car near the fuel tank i don't no about the mondeo i had one so bad it wouldnt let fuel though

Since last night I've found out that the fuel filter is part n parcel of the pump/sender unit. If that's blocked it means a new fuel pump/sender anyway... :-( looks like buying secondhand wasn't a good idea after all..... :-( 

Thanks for your help.

[Shane the Painter]

For anyone else reading this thread - an update since yesterday:- Got the car recovered to an experienced mechanic. He removed the used pump/sender unit I bought on Monday. Tested it on the bench to find that it has an intermittent fault and has to be tapped (quite hard!) to get it to work at all! 

Bottom line with this type of combined pump/sender/filter units is that any of those three elements can cause the unit to stop working, so the 83000 miles I got from the one which failed three days ago is considered VERY good service! The mechanic who established the fault with the s/h replacement has suggested a better way to approach these units is to have them replaced on a 'Preventative Maintenance' basis every 60k. Bearing in mind the unit for the Mk4 Mondeo petrol is £388 inc VAT, plus £150 to fit at a 'normal' garage (Ford main dealer almost certainly a LOT more!), that works out to less than a penny per mile... so for me, as this vehicle is a Licensed Private Hire Vehicle, that's cheaper than the car having been off the road for (at time of writing) 3 days losing around £200/day and it won't be ready until tomorrow night.... Hey ho.... Joys of motoring and all that.....