A bright idea to stop rust bits destroying fuel pumps?

I'm after some opinions so hopefully a few of you can help; Forgive the rather lenghty background but it may help…

I have a (new-to-me) '83 GTI 1.8, which was a non-runner. I established the fuel pump was not working, just a dull 'thunk' when powered up. 12V was there, so tried an old pump off my old Audi 80 and the car ran fine - for about 30 minutes. Then one time I turned the car off, when restarting the pump didn't run, just clicked as the original pump had done. I dismantled this pump later and found quite a few bits of rust within that could have jammed the pump I believe.

So, ordered a brand new pump from GSF, and to be prudent, cleaned the tank very thoroughly in situ to rid it of the rust bits from the old filler neck (new one fitted before my ownership), by using a telescopic magnet, air-powered grit blasting suction pick-up, and hoover nozzle (when dry). The tank was totally clean and in good condition as far as I could see - took me about 4 hours…

Fitted new pump, re-fuelled, started fine, and ran for about 10 minutes (fine under hard throttle too) before the pump packed up and 'stalled', this time blowing the fuel pump relay with it. Now I'm pretty sure another unseen bit of rust has jammed this new pump, and I don't fancy buying a new tank just to ensure the tank is clear of crap, or keep buying new pumps which last 10 minutes…

The tank has the black baffle box in it, together with a good condition cylindrical filter within, albeit with no 'bottom' to the filter, but this doesn't appear to be doing any good, SO, my idea is to route the standard 90 degree inlet pipe from tank to fuel pump via a simple in-line filter to protect the pump. This part is at low pressure so should be ok. My question is; Will such a filter. like the inline engine bay filters on carb'd Golfs allow a sufficient flow rate for the injection system, given that delivery is far greater than consumption?
And are there any other pertinant issues I'm missing?

Please help, as this is starting to get me down, and is also getting expensive!!

Don't know about allowing a decent fuel rate but some later pumps (and pierburg replacement ones) have a little mesh filter just before the inlet of the pump after the 90deg elbow… Could try something like that…

I had same problem as you and eventually lashed up an arrangement using fuel hose and the biggest plastic in line filter I could find. Used the orginal rubber elbow hose from tank to filter to hose in a loop to pump (I think). Cable tied up out of the way. Left it on for @5000 miles and then removed it. Its run OK since. I think I cut the rubber elbow so needed a new one :dontknow:

Use the filter from a fuel injected Rover Metro. There's a couple of options. The one you want is usually listed with a comment about M18 threads. There's an M14 version too. The M18 one has a large enough bore to replicate the pipe bore and the fittings are also compatible. I used some power steering pipes from a mk3 Cavalier so that I got some 90 degree bends, but M18 is a standard hydraulic thread so new fittings and ends can be bought cheaply. Not had a pump failure since I did it.

Thanks guys - some very valuable and much-appreciated advice.
An update - this morning, after much overnight thought, I decided to try to lash up the very same arrangement as Early-1800 had done, purely coincidentally.
Having looked at where I might mount it, not so low as to be under threat of damage from hanging too low, the only in-line filter I could think of was the little one that carb'd VW engines use, but was concerned about flow rate given that the bore of the supply and return spouts are 5mm, compared with 10mm for the original GTI pipe, which is a lot less. However, I filled a funnel with petrol and poured it through the little clear paper filter and the flow rate was surprisingly high - the paper filter didn't 'back-up' with fuel at all, so I thought it might work.

I cleaned the tank again, and this time poured 5 gallons of fuel from the tank, through a paper filter from one jerry can to another, about 4 times, to make sure the fuel was clean. This alone removed a lot of rubbish, which had abviously come out of the tank with the petrol. This may well have been half of my problem. I then made up a loop of petrol hose, with reducer sections, to fit the in-line filter between tank and new pump (which had just turned up by courier), tie-wrapped it up out of the way of the moving rear axle, and decided that it had better be tried… Also had to replace the 15 amp fuse as the stalling of the 'old' pump had blown the fuse.

Car started fine, the little filter is passing loads of fuel, and ran the car under hard throttle up the lane in 2nd and 3rd to be sure of sufficient delivery. I must say I'm a little surprised, but the car performs just as it should, good power, good tickover, good hot and cold starting, and only a very few bits in the in-line filter thus far. Can anyone see any problems of potential damage I might be doing using this method?

Good advice about the Metro filter though. My concern was I'd struggle in an auto factors as they'd just want a car model to raise a part number from, rather than be able to dig a load of filters out and let me see what might work best. So I'll keep that gem of advice just in case the little filter I have fitted does cause some problems in due course. But at the moment, all seems well.

Thanks again for the good help - there's obviously a lot of experience on the site! I'll keep you posted if there are further problems. Cheers.

The best way to clean out your tank is to swill with fuel and empty. Seems like doing that has removed most of the rubbish in there. As long as the filler neck is ok you shouldn't have any more problems.

Good thing about that filter is you can see any crap it catches and be certain when the tank is clean…

Good job!

Does anyone have a part number for the M18 Metro filter? I went to my local spares place today and all their catalogues piont to the same filter for the Metro GTi which had a thread measuring about 13mm internal dia so was probably a M16.

Alternatively can anyone suggest a suitable filter that doesn't cost $$$?

Cheers

can you suggest where i can buy a fuel filler neck for a cabriolet????

talk to Crazyquiff - he has a pattern that enables a tintop filler neck to be adapted - apparantly works pretty well.

M

could you also stick a big magnet to the bottom of the tank to help stop the bits of rust floating around?

Replaced fuel neck on mine as was really rusty ops: i then put a magnet in the tank and drove around for a week or so. There was loads of rust and crap stuck to the magnet and I had a clean tank at the end of it

Well I replaced the fuel pump (thanks caddyman 8) ) and it's been running ok for a couple of days so touch wood…

I checked inside the tank a couple of weeks ago and it looked clean. Out of interest where did you stick the magnet so you can easily get it out again?

Alos I noticed some very light whitish corrosion/oxidation on the first couple of inches inside the filler neck (got my hand all around the outside of the neck, totally sound) - could this be a problem?

Cheers all

When you put fuel in do you get a woosh on opening the petrol cap ?
If not might explain the oxidation ?
I put some magnets in a cloth bag tied with string (not the plastic type)
and put it in the tank through the fuel gauge sender unit located under the seat. Just unscrews leave some of the string outside of the guage so you can pull the magnet out to clean. I did it three or four times and it came up really clean I couldn't even see the bottom of the tank when I started.
There was a thread about it last year but can't remeber who it was
but it helped me no end but I'm still finding problems along the fuel systems but does look like it's coming to an end