Fuel Pump - Updated

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KarlH
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Fuel Pump - Updated

I went to start the car(2001 K series) this morning and don’t get the usual fuel pump whirring when you turn the ignition on and the car won’t fire up.

I’ve checked the fuse, inertia switch, and the Immobiliser isn’t on.

What can I check next?

Typical, was fine yesterday!

Cheers,

Karl

KarlH
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Sorted - the relay bypass fuse had blown.

KarlH
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Just went to use the car again, it fired up and cut out a few times and then the fuse blew again (assume that’s what the pop was followed by the fuel pump not starting again).

Any ideas what may be causing this and what I can check out tomorrow?

SM25T
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Might be a bit of corrosion in a connector or earth causing a high resistance. Do you have the right rating of fuse fitted ?
KarlH
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I’ll check connections tomorrow, was fine the day before!

fuel pump fuse is 15A 

Jonathan Kay
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Have you checked that the fuses are blown as well as that it worked for a bit after changing them? 

Have you got a multimeter and the appropriate wiring diagram?

High resistance will cause loss of function but it won't normally blow fuses.

If it is blowing fuses I'd start by:

  1. Looking for damage to wiring or connectors.
  2. Disconnecting wires at the fuel pump and seeing if it still blows the fuse. That should distinguish between faults in the pump and faults elsewhere.

Jonathan

Toby S
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Karl

Relay by-pass fuse ? I've got a 92 1400 supersport and haven't come across that - where is it ?

Kind regards

Toby S

KarlH
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I’m not convinced the fuses have blown - it’s certainly no different with a new set of fuses and they don’t look blown on closer inspection 

I have managed to get the boot floor up and tested the supply to the pump (I’m guessing the pump is on the top of the tank) and it has just over 4v getting to it. 

I know there was a previous thread about a similar 4v reading but it has no conclusion so I don’t know what the fix is and can’t get into the connectors fo test where the voltage drop might be! I did try a direct connection to the pump with a fly lead but it still didn’t make any noise.

I’ve checked earths, cleaned up connections etc and it’s non different. 

What else can I test?

@Toby S - the relay I referred to was put in for the K click you can get with the starter, it’s a mod to the MFRU.

Jonathan Kay
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... it has just over 4v getting to it. 

Where was that measuring between and was the pump still connected?

Jonathan

PROBE2
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Karl, the pump is on the side normally not on top, top is Sender.

KarlH
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Ah! Thanks. I thought being able to get to it fairly simply once I’d got the boot floor up was too good to be true. 

Looks like I’ll have to disconnect the fuel filler to get the floor out fully to get to it.