Ford Mondeo III (2000 - 2007) - fuel system sensors

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Sat 29 Sep 2007 15:52
fuel system sensors - michaelO
Our 2003 53 Reg Mondeo TDCI (115bhp) recently cut out just after refuelling. It had run enevenly just before refuelling.The engine would restart but only run for a second or two. The AA did a diagnostic check, which seemed to indicate a fuel pump problem. The patrolman cancelled the fault code & eventually started the engine. He followed the car to our local Ford dealer where they confirmed it was a fuel pump fault.
By now the car had run perfectly for 20 miles. They said they could not check anything as the fault had been cleared & the car was now running perfectly.
The Ford service people suggested the fuel level had been low & that sensors had detected air in the system which cut out the fuel pump to protect it - either that or dirty diesel (The tank was actually one third full on refuelling.) Although the car now runs OK, I read an answer in your column (15th Sept) about a BWW diesel with intermittent fuel pump problems (stalling) which you suggested could have been due to bad earths on the fuel tank lifter pump or its relay. Could this have been responsible, or as you say would it not have shown up on the diagnostics. Our car has also occasionally stalled on pulling off ever since we purchased it at 6 months old, even with resonable revs - The head-honcho at our Ford dealership merely says that they are prone to this!
Any thoughts?

{Post reformatted to remove all the >>>'s - DD}
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Sat 29 Sep 2007 18:00
fuel system sensors - kithmo
When you say the tank was 1/3 full on refuelling, do you mean before refuelling or that you put a third of a tank full in ?
The Mk3 Mondeo Diesel (and the Focus) have a "run rough" strategy built in to the Fuelling program that activates when the fuel is low, usually when the low fuel light comes on. This program is to conserve fuel at the expense of engine performance. If it was 1/3 full before refuelling then it could be that the low fuel signal to the ECU has got confused and switched into the low fuel mode. You may find that it does it again when the fuel gets down to the same level as before (let us know). Regarding the earth connection, I have heard of one instance of this on an early Mk3 Mondeo (TDDi IIRC) where a guy bought a new pump onlty to discover that it was the earth, but only the one.
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2005 Ford Mondeo Zetec 2.0 TDCi 130ps
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Mon 1 Oct 2007 15:45
fuel system sensors - michaelO
The Mondeo did not "run rough" - it just started for a second & cut out immediately each time. The car was more than a third full before refuelling & the low fuel warning did not activate. My wife is too nervous of it happening again, so she now refills at half full!
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Mon 1 Oct 2007 22:49
fuel system sensors - TurboD
Time to sell, now- before the big bills roll in -sorry
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