Fuel pumps failing frequently?

[kentishS2]

Many S owners have replaced their fuel pumps almost as frequently as their Throttle Pots'!

It appears that this may be due to the pump not having any pre-filter. My new Bosch pump stated that it MUST have one before the pump to protect the pump. Seems logical to me. The only trouble was that I was unable to get a filter with such large connections but I have found that Demon Tweeks sell fuel filters with large connections possibly suitable for use as a pre-filter on the S.

I haven't measured the sizes yet of the connectors on the car fuel lines but I think that they are smaller than the largest size Demon Tweeks sell.

I'll post further details when I have the chance to investigate further.

[greenv8s]

Many?

The tank has an internal mesh filter. If this becomes clogged then it can restrict the flow to the pump. High pressure pumps don't like sucking against a restriction, this leads to cavitation and overheating inside the pump, the pump then fails prematurely. You can often hear the difference in the sound of the pump when this is happening. I would advise you to get the mesh filter cleaned every few years and any time the tank has been run completely empty.

[kentishS2]

greenv8s said:

Many? The tank has an internal mesh filter. If this becomes clogged then it can restrict the flow to the pump. High pressure pumps don't like sucking against a restriction, this leads to cavitation and overheating inside the pump, the pump then fails prematurely. You can often hear the difference in the sound of the pump when this is happening. I would advise you to get the mesh filter cleaned every few years and any time the tank has been run completely empty.

Yep, several have commented on pumps failing and I'm on my third and I guess there will be others who didn't read the thread or comment on it.

Thanks Peter, I wasn't aware of the strainer in the tank.

So, adding yet another filter will restrict flow further and make matters even worse!

My pump did sound different the other day and I thought "Oh sh!t ...not again"

My tank leaks around the sender and requires replacement anyway as new senders and sealing rings still leak, so I'll do away with the in-tank filter and go for a filter housing and replaceable element so that it can be replaced periodically. I've yet to have the tank made but I'll specify no in tank filter.

Thanks for that info.

Cheers,
Kevin

>> Edited by kentishS2 on Wednesday 28th July 12:04

[greenv8s]

The hotter the fuel is the more apparent this problem will be. Since the fuel is heated up in the fuel rail this heats up the whole tank in hot weather, which can eventually get to the point where even a normal healthy car will show the cavitation symptoms of a noisy pump and lost fuel pressure. If it only happens when everything is stinking hot it is probably down to the fuel rather than the filter or pump. But if it happens under more normal conditions I would suspect either the pump is knackered or the filter is blocked (which will shortly lead to a knackered pump).