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I have a Nissan Primera P12 2001 (2500cc) which was working without any issues. Yesterday when I try to start, it wouldn't.

Talking to the repair guy said it was the fuel pump. But later he said it is the crank sensor at fault, which prevented the car from starting due to sending bad readings to the computer, but I still have to replace the fuel pump, as it failed too.

So my question is, can a problem in crank sensor cause fuel pump failure? or is it pure coincidence? (or I'm about to pay too much money)

(I don't know what crank sensor does)

UPDATE: I was told both crank position sensor AND cam sensor needs replacing. I believe this is the model I have http://www.carfolio.com/specifications/models/car/?car=232980

UPDATE 2: Here's the photos of the faulty fuel pump http://imgur.com/M9ymIAQ,rGUXsSg

  • This may be obvious, but which fuel does this car use? If it is a diesel, is it a low pressure or high pressure pump? – HandyHowie Nov 18 '15 at 8:16
  • its a petrol car. Evidently there are 2 pumps. One closer to the tank and the other closer to the engine. One closer to the engine is the one that needs replacing. – Madushan Nov 18 '15 at 11:00
  • I'd be very surprised if there are two pumps on this car, unless it employs Gasoline Direct Injection (GDI) – Zaid Nov 18 '15 at 14:30
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    In that case a picture of the suspect part would be useful. It would be funny if the part being labeled a fuel pump turned out to be a fuel pressure regulator. – Zaid Nov 18 '15 at 14:42
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    The link in the update indicates that your Primera employs "direct petrol injection", which explains the presence of the two pumps (another way to say gasoline direct injection) – Zaid Nov 19 '15 at 4:30
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Sounds strange.

I can understand that the absence of a crank position sensor signal can prevent the engine from starting (the ECU won't allow the car to run without it). The lack of signal could also prevent the fuel pump relay from activating and priming the fuel lines.

But I'm struggling to buy that a bad crank position sensor would result in physical failure of the fuel pump.

Electrical fuel pumps usually fail when the brushes in the electrical motor wear out, weakening the ability of the pump to pressurize the fuel.

It could be that the mechanic wants to replace the fuel filter that has clogged up over time, and the fuel filter is part of your vehicle's fuel pump. However, most fuel pumps should allow you to replace the fuel filter without having to swap out the more expensive fuel pump.

  • I agree, this does sound odd. If I was to guess, the mechanic has probably broken one of the things he is claiming is at fault. – HandyHowie Nov 18 '15 at 8:18
  • he specifically said that he is getting me a second hand pump, coz a brand new one would cost over 1700 (NZD), so the second hand unit is around 300 (NZD). (He didn't mention anything about the fuel filter) Two faults may not be related, but I too am curious as to whether its pure coincidence or not. Any advise ? – Madushan Nov 18 '15 at 11:11
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    @Madushan Coincidences are highly unlikely. I'd ask him how he determined that it failed. Did he measure low fuel pressure to confirm it? If so, how did he rule out a clogged fuel filter or bad fuel pressure regulator? Many people might argue that for a 14 year old car (assuming the fuel pump is the original one) that it is not a bad idea to replace the fuel pump anyway, but I personally would like to be 100% sure that it has indeed failed before dropping in replacements when they weren't really needed – Zaid Nov 18 '15 at 11:32
  • I'm not sure if the pump was the original or not. Car is an import, and I'm the first owner in this country. Odometer is just under 90,000KM. (bought 3 years ago at 60,000km and only changed brakes pads and rotors (worn out), air filter, and drive belt (it had cracks according to the same tech guy) since. So I think it's safe to assume the pump still the original? – Madushan Nov 18 '15 at 13:52
  • @Madushan it might be the original one but my point was that replacing it is unnecessary if it is in good order – Zaid Nov 18 '15 at 14:24

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