Fuel filter position

[lukasdeopalenica]

Does anybody know why a fuel filter was placed after a fuel pump? In this arrangement all dirt is drawn through the pump and then trapped inside the filter. I am thinking about moving it before the pump as it looks more reasonable to me. However there is a difference in pipes diameters before and after the pump.

[Neil-yaj396]

I think it was just a convenient spot to plumb it in? The other side of the pump is a shorter run and crowded by the dipstick etc. In the mid 70's a filter on a non injection car was a bit of innovation as with many things on the Beta.

[betaveloce]

@ Neil-yaj: I think Lukasdeopalenica is referring to the large filter which is mounted on top of the rear axle, next to the electric Bosch fuel pump, as his HPE is a i.e. version

@ Lucas: normally there should also be a pre-filter inside the fuel tank, so before the pump (carb as well as injection) 

[WestonE]

Lucas

Really you should have filters on both sides. If the injection pump fails it will send its swarf straight to your beautiful precision injectors which will then be a lot less precise!

Eric

[lukasdeopalenica]

That is the explanation. Bosch engineers, as they probably design the fuel system, intended to protect injectors not the pump. Do you mean filters of the same type, or any extra one before the pump?

[lukasdeopalenica]

I am going to use an extra filter before the pump. Can anyone recommend any good filter? The problem is I cannot find filter with both 12mm terminals. What may happen if I place filter with smaller openings? May this reduction influence on the pump operation? I found one with transparent and compact body, but it has both 8mm terminals.

[thecolonel]

Clear filters are usually for carb cars, I don't think it can take
ie pressure and could explode. You will need the metal cased
fuel filter designed for fuel injection.

[lukasdeopalenica]

You are right, but I think high pressure is built behind the pump where the fuel is forced, while before it the pump just sucks fuel. This however can increase underpressure before the pump as the opening will be smaller. I am wondering if it does not impact on the pump or its efficiency. 

[lukasdeopalenica]

Okay, the filter has been fitted and all seems fine. However I have not tested it on road yet
The main reason for fitting this filter was failure of my old pump that broked suddenly, probably of age but when I dismantled it and looked inside dirt, rusty debries etc just horrified me. The pump just before saying good bye worked very noisy. The lesson I have learnt from this situation is all components that can be renewed when you have a chance and/or good access (I mounted an old one when I reassembled the car after respraing) should be renewed.

[MattNoVAT]

Yes, I fully agree with the comment on replacing old components.  There is nothing worse than finishing a project then having to take it apart to replace an old component that was easily accessible earlier.  E.G. Replacing water pumps when doing the cam belt.

[lukasdeopalenica]

The pump after few minutes of operation is getting noisy. I wonder if this is caused by quite low fuel level (ca. 12ltrs) or reduced feeding pipe diameter before a fuel pump :/

[rachaeljf]

The pump pre-filters as used on Uno Turbos for instance seem difficult to find these days. The pre-filter should be a wire mesh strainer rather than a super fine paper filter as used after the pump to protect the injectors. Here is a suitable pre-filter for the FI pump:

http://inlinefilters.co.uk/index.php?main_page=product_info&cPath=918_975_976&products_id=10108

Cheers R

[lukasdeopalenica]

Thank you very much Rachael, that it's exactly what I was looking for

[lukasdeopalenica]

Problem solved by the suggested filter. It fits and works just perfect. Thanks.

[Sandro]

Hello everyone,

I'm following a very old thread here, I'm looking for an appropriate filter to locate 'before' the Fuel pump on an Injected 2L model.
( the product link here has disappeared )

Thanks Nigel and Kevin for your help this weekend!

Cheers Andrew   

[Nigel]

Andrew,
This appears to fit your needs, stated as pre-pump and 12mm in and out.

https://www.carbuilder.com/uk/12mm-12-inline-fuel-filter


Good luck
Nigel

[Sandro]

Nice one, thanks Nigel,

Rachael on the original thread was also kind enough to send me this link if any other members are interested,

https://www.inlinefilters.co.uk/Filters-Fuel/Inline/MetalStrainer/FIN-FF30145

It also has a 12mm inlet/outlet which is perfect.

Thank you both.

Andrew