UK Car Repair: Astra 1.7dt fault code, crankshaft sensor, wiring loom

Question
QUESTION: car diagnosed with code PO 0251 reads, injection pump fuel metering control "A" malfunction (cam/rotor/injector)garage mechanics seem confused any idea what part or parts are defective, Original fault was car stopping as if ignition turned off, wait 2 mins then ok again

Many Thanks

ANSWER: Did you get my response earlier?

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QUESTION: Sorry have had no other response
ANSWER: Sorry, I did answer it. What is the position right now. Is the light still on?  Did they erase the code when they checked it?  When these things happen the procedure is to clear the code then drive the car to see if it happens again, it may not.  If they have no idea of what is wrong then you need to take it to someone who does.

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QUESTION: Fault was cleared by mechanic drove car for 2 days no problems then car stopped as if ignition turned off and refused to start again, ECU read and shows same fault code mechanic unsure if ecu, wiring loom, or diesel pump, at fault ECU has been cleared form fault as test showed No faults,(i seem not to trust engine management readers as seem too vauge in fault diagnostics)

Thanks for you input

Bob Taylor

Answer
The readers only state the result, the cause has to be diagnosed. My first suspicion would be the crankshaft sensor.  Often it is worth taking it off and cleaning it. it can also be tested, it should be magnetic and with a multimeter you can see if it actually works by operating it with a piece of iron.