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D4D (4.2) Diesel Leak & Uneven Running

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Dear All, My 4.2 D4D , 65,000 mi, has recently had a new DMF, clutch & timing belts. Upon return form the garage, it has run a little rough.

At first running lumpily on tick over when cold & belching a few black clouds of exhaust smoke at low rpm, then leaving drips of diesel whilst parked and now briefly smelling of diesel in the car upon restart after running for long enough to warm the engine and a very noticeable flat spot at around 1500 rpm when running on the flat or downhill. Pumping the fuel filter pump seems to need ax 8 - 10 pumps before it firms up after standing overnight. The car always starts well but misses slightly at tick over - perhaps less so after pumping.

There is some fuel leakage (but not much)around the injection pump and below this area down to the sump but no leaks around any of the eight injector pipes (where they screw into the cylinder head) or the electrical connections on top of the engine. The car has gone into safety mode (yellow engine warning sign & vastly reduced power) on three occasions - exactly at the same place each time: ax 1.5 miles from home when climbing a gentle hill with an engine that has already been run that day but then cooled down again. On each occasion , I have stopped , pumped the fuel filter head pump ax 8 times & it has run normally thereafter aprt from its flat spot at ax 1500 rpm. I have never had any fuel filter warning lights and the filter is not due for change. Air filter was changed just before the engine out. The SCV's were changed at ax 20,000 mi

Other than smelling of diesel post start up , lumpy running at (cold) tickover & the 1500 rpm flat spot it runs well & smoothly at all other revs , there are no exhaust fumes . Fuel consumption seems normal.

The (non Toyota) garage who fitted the DMF & timing belt could initially find no real fault & suggested injector cleaner. Their diagnostic computer showed no faults . Having indicated the fuel leak around the injector pump they now think that it may need a new injection pump but I would like to know that that this is really the case ! I have booked into a Toyota main dealers for them to check it but would love to hear some unbiased theories before hearing what the local dealer has to say....

Thanks in advance for you advice. Sean

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