D5 (D5244T to 2005) In tank fuel pump buzzing?

[Bernard333]

The rotor and bushes are constantly immersed in diesel and designed for that so I think your right that if it runs dry it will quickly get damaged , its quite a powerful motor for the size of it . Due to a certain driving style my pump would certainly have regularly run dry so I am not surprised it eventually failed ( I can say this now with the benefit of hindsight ) . I stripped the pump motor and it failed due to brush wear , they would not be easy to replace but when I put it loosely back together it came back to life , problem is I cut the metal case open to get at it so its really knackered now , was thinking about welding or brazing it but you have to draw a line somewhere .

[carl4u44]

Great post Bernard. I have now obtained my second hand petrol unit complete with fuel guage sender unit etc. I understand now the ridgit plastic pipes your on about. I have even tested the motor with a 12v battery on the blue and black wires coming off the electric motor.

Now to be brief, having returned from the scrappie, the buzzing has completely stopped! I now wonder if the pump has failed all together and the the main engine is doing the fuel drawing work?? As the car is running and starting good. But now I cant even hear the slightest hmmm...

I could remove fuse no. 33 and fire up the engine to test this theory but now Im unsure what to do next.

To note I also see from the picture above that this type of motor is a turbine type, which are meant to be very stable in providing a constant flow!

[Bernard333]

Carl , I would think your motor is still working , on my D5 there is no way it will start without the in tank pump even with a warmed up engine , the injection pump suction is enough to maintain cruising at 50 mph on a flat road but as soon as you need acceleration it needs the help of the in tank pump . I know you have looked at the electrics but is there a possibility the fuel pump control relay is sticking on sometimes , I have a lot of experience with industrial contactors and circuit breakers welding themselves in the on position but car relays I dont know if they are prone to do this or have a tendancy to ocassionally stick on but I dont see why they should be any different .

[carl4u44]

Is there a way of testing the intank pump? Can I take a small rubber hose off the engine fuel pump and turn the ignition on?

'the injection pump suction is enough to maintain cruising at 50 mph on a flat road but as soon as you need acceleration it needs the help of the in tank pump'

As what you mentioned. I did this today and got the 'engine service required urgent'. Would not restart n side of road. Codes read: 1)fuel pressure low. 2)small leak detected. Will be changing the fuel filter in the morning (12000 miles old)

[fungus]

To test fuel flow from the in tank pump open the drain screw on the bottom of the fuel filter. fuel/water will drain out under gravity. Turn ignition to 'on' the pump should start up and if its working corectly fuel flow from the filter will increase.
HTH

[carl4u44]

I'll give that a go later!

[carl4u44]

update, no fuel coming from filter with red on. Checked the fuse too and thats ok. Now lifting the rear seat!

[Bernard333]

Carl , before you go to the trouble of completely removing the fuel pump check that the pump is getting 12V delivered to the connector on top of the pump with ignition on and engine off and that the return to earth is a good connection , I doubt this is the problem but dosnt take much time to do and at least you can then rule out the relay and power supply . When I replaced mine for the second time in December its still leaking diesel from the tank where the sealing ring is not seating correctly so I cannot have the tank more than half full which is not a great hardship but I will have to revisit the fuel tank and do the job properly . Another easy test under the bonnet , remove the short rubber fuel feed pipe feeding low pressure fuel to the high pressure injection pump , this should spurt out fuel with the ignition on this rules out any blockages between the fuel filter and the high pressure pump . You may need to use a new jubilee clip . Something I have noticed since replacing the pump is that my fuel consumption has increased a lot , this does not make sense and I am looking for other causes ( the tank is leaking a little but not enough to explain where the fuel is going ) .

[carl4u44]

ok got the fuel pump out. the casing looks slightly different to the petrol one i have. I applied my own 12v to the blue and black pins of each pump and mine is not working!

[carl4u44]

yep both part numbers on the electric bosch pumps are different!