XJS ( X27 ) 1975 - 1996 3.6 4.0 5.3 6.0

Fuel pump noise? normal / concern?

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Old 06-19-2017, 11:52 PM
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Default Fuel pump noise? normal / concern?

I've noticed my car's fuel pump is hissing and crackling, I've never really been back behind the car while its running so this is the first time I've really noticed it and the noise gave me pause to consider how much its going to cost this time.


https://www.youtube.com/watch?v=dE-l...ature=youtu.be


Despite the noises the car is quite quick, 10-11mpg mixed driving, idles smooth. I'm going to assume this isn't 'ideal' ?
 
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Old 06-20-2017, 12:45 AM
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That sounds like it could possibly be cavitation in the pump. It is possible that the gravity fee to it is partially blocked. It might be worth cleaning out the sump tank and changing the sump tank's sock filter, as well as changing the feed pipes from the main tank to the sump, and from the sump to the pump. Of course, it could just be the pump failing! Either way, it needs fixing, that is for sure.
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Old 06-20-2017, 03:58 AM
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New Fuel Pumps are not that expensive, as they are generic and fitted to lots of different makes of Cars.

I got one off ebay with a 2 year Guarantee for abt £27 (UK) and Yes it is a bit noisy but after a while you don't notice it.

I think that some of these pumps may be badged, so paying any more than that won't always mean that the pump will be any quieter.
 
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Old 06-20-2017, 09:32 AM
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If your is like my 92, 5.3 there is no sump tank. There is a sock filter on the inlet and it sets in a foam support that could degrade and plug it. If it idles normally and doesn't show signs of roughness under load, then it is unlikely to be cavitating. If you hear the noise at idle try installing a fuel pressure gauge. I've had pumps make noise for quite a while before quitting. I'd plan on a new one though. I just had another thought. If the foam rubber support degrades enough to allow the pump to contact the tank, I'm sure it generate a good deal of noise. Wonder if that has happened to anyone?
 
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Old 06-20-2017, 10:53 AM
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Originally Posted by catterwaller
If your is like my 92, 5.3 there is no sump tank. There is a sock filter on the inlet and it sets in a foam support that could degrade and plug it. If it idles normally and doesn't show signs of roughness under load, then it is unlikely to be cavitating. If you hear the noise at idle try installing a fuel pressure gauge. I've had pumps make noise for quite a while before quitting. I'd plan on a new one though. I just had another thought. If the foam rubber support degrades enough to allow the pump to contact the tank, I'm sure it generate a good deal of noise. Wonder if that has happened to anyone?

I was about to order new pressure regulators prior to discovering this maybe that will clear it up.
 
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Old 06-20-2017, 10:58 AM
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Originally Posted by VancouverXJ6
I was about to order new pressure regulators prior to discovering this maybe that will clear it up.
Your 1989 car does not have the facelift intank pump. It has the external pump and sump tank setup.
 
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Old 06-20-2017, 11:52 AM
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Originally Posted by Greg in France
Your 1989 car does not have the facelift intank pump. It has the external pump and sump tank setup.
I know, Im afraid to touch it and risk spilling fuel everywhere, id imagine you'd have to pump out every last bit of gas as its the lowest point in the system.
 
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Old 06-20-2017, 12:22 PM
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Originally Posted by VancouverXJ6
I know, Im afraid to touch it and risk spilling fuel everywhere, id imagine you'd have to pump out every last bit of gas as its the lowest point in the system.
Lookunder the boot floor, under the sump tank, you will see a rubber bung. Remove it and you will see the drain plug in the bottom of the sump tank. You drain out all the fuel through this. Then remove the carpet before getting stuck in.
Greg
 
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Old 06-20-2017, 04:00 PM
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Hi VancouverXJ6

This is where you find the Rubber Bung that Greg was talking about.

Pull out this Rubber Blanking Plug and you will see The Fuel Drain Tap.

Put a piece of Tube on the Spout, then turn on the Tap and Drain the Fuel.



Location of Fuel Sump Drain Plug




This is the Sump Tank Drain Tap
You will need a Socket to turn it on.
 
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