Fuel pump internal filter?

[Loach1]

Just a quick question, I can't find a definitive answer....

Does the stock inline Bosch fuel pump have a strainer in the inlet side? I've read about a small thimble that can be removed and cleaned, but I'm not sure if this is on the stock pump?

I have a surging at steady speeds that feels like inconsistent fuel delivery, that started after running out of petrol. I checked the main filter and that is like new inside, and the pump is nice and quiet.

Thanks!
David

[chiefyo]

Gauze filter in swirlpot at bottom of fueltank at least there is on my 3C. Accessed by removing locking ring holding in metal plate, behind this is a flat rubber sealing washer. Get replacements for both of these ready to fit before attempting removal as old items will not seal seffectively and this sits above exhaust !!!!

[BountyHunter]

Loach1 said:

I have a surging at steady speeds that feels like inconsistent fuel delivery, that started after running out of petrol.

it shouldnt happen, but could it be some sort of air lock ?

[Barry S1]

My S1 has no swirl pot in the tank but a filter
tank side of the pump, but i don't think they had one
from new, my old pump never had anything in it when i
changed it this year, have you checked the filter
in the engine bay ,best to just renew it then you know its OK

Barry

[Loach1]

I checked the parts catalogue and see that the S1 tank does not have any sign of a filter inside, or one before the pump for that matter. There is a pressure accumulator after the pump, then the large filter under the bonnet. The large filter had no real restriction when blowing through and looked very clean inside, so I put it back on. It seems that from the factory there is nothing to prevent the pump from crud, unless the reports of a thimble filter in the inlet are true....

Removing and refitting the filter introduces a lot of air in the system, but it started after a few seconds, which would have included refilling the large filter, so I don't THINK it has an airlock.

For today's efforts, I just poured some Seafoam in the tank and hope it can work some magic. I've always been impressed with the product when removing carbon build up at the top end, so fingers crossed! If it is still rough by the weekend I will have to get a closer look at the pump.

[dryden]

My S1 has a six bolt flange on the bottom of the tank, inside which is a boxed off section with feed holes and a plastic filter push fitted on to the inner side of the feed pipe. I discovered this when the petrol pump was making slurping noises, what had happened was the plastic filter had come off the pipe, and unable to float away because of the boxed off bit, blocked the pipe!..... So I took it off, and binned it!......

[greymrj]

The fuel pumps are available from different makers. Some definitely have a small filter in the input end. The one I took off had, and it was completely full......certainly proved to be the immediate cause of fuel starvation. (The ultimate cause was of course rust from the tank). Take the pump off, let it dry completely, at least overnight, stand it on end (input side down) and tap it down gently....see what comes out. The pumps which do not have an obvious filter also seem to be able to trap some crap, I took one of those off and treated it in the same way and some muck did come out.
My tank also seems to have had a plastic filter at some time but wasnt complete. I now have an expensive, but highly efficient, full flow in line filter between the tank and the pump. It screws apart and has an internal cartridge filter which is very cheap to replace. Came from Demon Tweeks. If anybody is interested I will loo up the details.