The only issue with the extra inline filter on a D (between pump and carby mostly) is that people forget about or do not realise there is a filter in the tank that could be completely choked.
1971 D Special wiring problem.
- Thread starter Greenpeace
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David makes a valid point re the in tank filter, which is a rather unusual design of stacked flat washers. BUT you have to know it is there. Removal can be messy as it is fitted to the lower surface of the tank which means the volatile liquid will probably suffer the effects of gravity once the 21mm bung is removed.
I read a recent comment on facebook DS stuff someone was redoing their tank, had split it open to clean (absolute mess) and suggestion was to ditch the washers altogether and add a filter. I thought the actual correct place to put a fuel filter was before the pump, at the base of the H frame where it moves from metal pipe to fuel hose.
I can't speak for a DS mechanical pump, but some fuel pumps don't like pulling through the extra resistance of a paper filter.
Having said that, when I bought it, my DS had an inline paper filter both before and aft of the pump and it ran fine.
I replaced the pre pump filter with a one way valve to try and improve the starting time when the vehicle hadn't been run for a week or two.
Didn't work, that's why I tip a bit of petrol down it to save the starter motor some work.
I reckon the high micron "metal case" filters would probably be better than these plastic ones tooMe too, but I've be been shot at before.
The one in the tank is 20 micron whereas a paper fuel filter is usually 10 microns.
I guess it's up to the individual what goes through their engines?
This is the first inline filter I removed from mine 3 months after I put it back on the road 3 years ago.
I'd prefer this dirt didn't find its way into the carburettor and engine, but hey that's just me.
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they are certainly much larger!
that thread is here, on aussiefrogs with piccies. Do a search and I bet you find it
EFI never had the stack of discs on the tank and replaced it with an EFI filter between the tank an pump. You could fit a filter before the carby fuel pump if you wanted to, but most are after the pump for convenience. If you don't replace the plastic filters often enough it might also break and leak a lot of fuel because the pump only stops pumping when the float valve in the carby stops the flow. With the extra filter installed, you could probably delete the discs in the tank as for EFI and eliminate that maintenance item for good.
I reckon the only reason you would ditch the washers would be if you had that much crap in your tank it blocked up every time to drove it.that thread is here, on aussiefrogs with piccies. Do a search and I bet you find it
Sure you can blow back down the fuel line and clear it, but the crap's still there.
If you remove the in-tank one, and put an inline filter in, every time you change the filter the rubbish is being completely removed from the fuel system.
Yes, removing the tank and cleaning it out is the right thing to do, but there's a few threads on here that show what a PIA that can turn into as well.
Incidentally the brass shim style fuel filters were quite commonplace on vintage Pommy cars, usua.
there is also a brass/nylon disc type filter in some of the fuel pumps used. so you have two layers of stacked disc filters on the carI reckon the only reason you would ditch the washers would be if you had that much crap in your tank it blocked up every time to drove it.
Sure you can blow back down the fuel line and clear it, but the crap's still there.
If you remove the in-tank one, and put an inline filter in, every time you change the filter the rubbish is being completely removed from the fuel system.
Yes, removing the tank and cleaning it out is the right thing to do, but there's a few threads on here that show what a PIA that can turn into as well.
Incidentally the brass shim style fuel filters were quite commonplace on vintage Pommy cars, usua.
With the in-tank filter only being 20 microns the 19 micron particles that got through it would have had a field day in a FI system.
I guess Citroen figured why waste the money on the in-tank filter when it's not fit for purpose on an FI car.
"I replaced the pre pump filter with a one way valve to try and improve the starting time when the vehicle hadn't been run for a week or two."
...thats enough anecdotal evidence to dissuade me from installing a one way filter!
...thats enough anecdotal evidence to dissuade me from installing a one way filter!