Dirty fuel (I think) - UPDATE: carbie shenanigans

paladin Slammed & Awesome Dubber

79 posts · joined Jan 2009 · 2 Jan 2009, 7:48 pm

#686991

Hey all!

Well I have what I think amounts to a dirty fuel problem. I've just been away for 5 weeks in Laos, and the day before I left wouldn't you know it I have a massive fuel leak from the bottom of the tank around the tap. I lost about 20 litres of fuel on a 20 minute drive home from work. Erk!

Anyway, sent it off to a local tank repair shop when I got back (a week and a bit ago) and they fixed it. They gave the tank a light respray of something black on the exterior. Anyway, get it back, install it, fill it up to the rafters and notice that there is a leak in the seal around the sender. So I take the sender out to have a look and maybe put some fuel gasket goo around there. What happened is that the fuel in the tank bubbled up with the sending unit out, made contact with the surface of the tank (freshly sprayed with the black paint that is thinned by petrol) and some petrol complete with a bit of black paint then sunk back in the tank. So I knew I had some contaminant in my fuel tank, but basically hoped for the best, cheery idiot that I am.

So now I'm getting what I reckon sounds like fuel blockage. I drive her and then she starves of gas and cuts out. I then need to sit there and try starting her again a few times. After a while the fuel pump (which should be ticking over regularly but has stopped) starts up again and I'm good to go - anywhere between 100m and a kilometer before the same thing happens again. The fuel pump is an aftermarket electric one mounted behind the rear seat.

I'd basically like any input anyone can give me about what I should do!

I have some questions:

1. The best thing to do would obviously be to empty the tank and start from there cleaning lines etc front to back. The tank is about 90% full at the moment, though. Anyone know the best way to drain an almost-full tank? Just remove it and be ready with a jerry can when I diconnect the bottom hose?

2. Do all bugs have fuel filters in them by default? If so it will live somewhere between the tank and the pump, right? That will be my first thing to check/clean. And sorry for the dumb question - but I've never needed to do anything with a fuel filter before. Erm. . . what do they look like?

3. What else should I check/clean do you reckon? Do I need to blow all the hoses, clean out the carbiie, check plugs etc etc?

Basically what do you think the steps you'd follow would be if you were in my situation? Giving yourself a big smack on the back of the head being high on the list of course.

Oh - and does this sound like dirty fuel to you? It would seem a coincidence if the pump had failed or similar so soon after the tank being replaced.

pod i`ve got to finish this thing one day

4,980 posts · joined Dec 2003 · 2 Jan 2009, 8:01 pm

#686995

if it has a fuel filter its most likely blocked up 🙁 , if it hasnt got one i`d get one pronto ... then id be cleaning the fuel lines out and the carby as well,it could also be the filter in the bottom of the tank as well , so draining the tank most likely will have to be done.and whilst you are there you might as well put new rubber fuel hosing in as they dont last forever.. a little trick when having to drain the tank is to use some vice grips to close the rubber hose up under the tank then release and tighten to let the fuel flow into your gerry can 🙂,hope this makes some sense 😁

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paladin Slammed & Awesome Dubber

79 posts · joined Jan 2009 · 2 Jan 2009, 8:10 pm

#686998

pod wrote:if it has a fuel filter its most likely blocked up 🙁 , if it hasnt got one i`d get one pronto ... then id be cleaning the fuel lines out and the carby as well,it could also be the filter in the bottom of the tank as well , so draining the tank most likely will have to be done.and whilst you are there you might as well put new rubber fuel hosing in as they dont last forever.. a little trick when having to drain the tank is to use some vice grips to close the rubber hose up under the tank then release and tighten to let the fuel flow into your gerry can 🙂,hope this makes some sense 😁

Hey pod! That's a great trick. Thanks. I'd not have thought of it. That at least alleviates my concern about fuel going everywhere if I have to take the tank out! I already put in the best new hosing I could get from Repco when I swapped the tank over and have plenty left as they only sell it by the meter.

If the only fuel filters that might be found are aftermarket in-line ones then, nope, I don't think I have one as I couldn't see anything - so will go get one pronto. It should sit between the pump and tank rather than the pump and carbie - right?

How exactly does one go about cleaning the filter in the bottom of the tank? Is there always one? EDIT: found the answer to this one myself - including the link here if it's of use to anyone else. Good detailed instructions on cleaning the in-tank fuel filter: http://www.vw-resource.com/fuel_filter.html

Would any kind of fuel additives help here do you think?

Thanks heaps for the speedy reply!!

greedy53 Bishop of Volkswagenism

3,062 posts · joined Mar 2006 · 3 Jan 2009, 9:04 am

#687051

there is a fuel filter in the tank on older models they are on the end of the pickup pipe on newer bugs there is a copper plug that when removed lets access to the filter if there still in toss them they will cause much crying and teeth nashing and with the modern in filters much better
welcome to the wonderful world of vw's

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Joel Now containing 100\% E-Wang

9,368 posts · joined Feb 2006 · 3 Jan 2009, 9:28 am

#687057

Hey Craig, pod and greedy have covered it pretty well

standard bugs like yours never had an inline filter

all they had was a gauze over the pick up in the tank and another gauze inside the fuel pump
problem is aftermarket filters dont have the gauze and your pump is electric anyway
which leads me to the next point, you say its mounted behind the back seat?

elctric fuel pumps need to be gravity fed so the best spot is under the fuel tank,
they dont suck up hill to well
id be searching for an inline filter somewhere between it and the fuel tank and if there isnt one, fit one
pump may be clogged up with crap

also if your having trouble with the engine idleing assuming it still has a standard solex carby check the idle jet isnt clogged up

its on the RHS of the carby above the generator and below the big round electric choke unit
brass 8mm hex head take it out and see if theres abit of rubbish in the little pin hole in the tip

when u screw it back in dont tighten the buggery out of it either it distorts the seat in the carb

HTH

paladin Slammed & Awesome Dubber

79 posts · joined Jan 2009 · 3 Jan 2009, 3:22 pm

#687110

Joel wrote:Hey Craig, pod and greedy have covered it pretty well

standard bugs like yours never had an inline filter

all they had was a gauze over the pick up in the tank and another gauze inside the fuel pump
problem is aftermarket filters dont have the gauze and your pump is electric anyway
which leads me to the next point, you say its mounted behind the back seat?

elctric fuel pumps need to be gravity fed so the best spot is under the fuel tank,
they dont suck up hill to well
id be searching for an inline filter somewhere between it and the fuel tank and if there isnt one, fit one
pump may be clogged up with crap

also if your having trouble with the engine idleing assuming it still has a standard solex carby check the idle jet isnt clogged up

its on the RHS of the carby above the generator and below the big round electric choke unit
brass 8mm hex head take it out and see if theres abit of rubbish in the little pin hole in the tip

when u screw it back in dont tighten the buggery out of it either it distorts the seat in the carb

HTH

Thanks Joel! I definately owe you a beer or three at the VW meet here in Feb.

Today I removed the tank (lots of bother as it was almost full - lifted it up and crimped as per the suggestion above, but when I went to drain it into the jerry cans I had set up, not a drop would fall out of the tap underneath by gravity. That was my first clue that the fuel was, indeed, dirty. So after getting the fuel out, pulled the tank and found the pencil filter inside was VERY dirty. Also the fuel out of the bottom of the tank that drippe dout when that was removed was very dirty looking). Gave the tank a flush until running clean. Disconnected fuel lines and blew them out with my compressor. Installed an in-line fuel filter next to pump on the tankward side.

Reconnected, drove to the servo and filled up with fresh fuel.

Still having the same problem. Running rough as guts and getting starved of fuel.

I notice that the inline filter is filling only to about the halfway mark (enough to cover the inlet and outlet) but not the whole way. Maybe there is a problem having it mounted where it is, as you say, Joel? It's never missed a trick before, though. Been very reliable.

Mr carb is a Solex 34 pict 3 and I reckon it might be clogged. So am off to do as you suggest mate and have a squiz at that jet!

paladin Slammed & Awesome Dubber

79 posts · joined Jan 2009 · 3 Jan 2009, 5:11 pm

#687123

And now I'm wondering if I might need a new fuel pump too. Will start a new thread.

grumble Son of Jim - Creator of Good

2,672 posts · joined Jun 2008 · 3 Jan 2009, 6:23 pm

#687134

As silly as it sounds if you pull the hose off where it goes into the chassis at the front does the fuel still flow freely as when you cleaned the gauze. It may be blocked in the tap or the gauze may be buggered.

paladin Slammed & Awesome Dubber

79 posts · joined Jan 2009 · 3 Jan 2009, 7:37 pm

#687151

grumble wrote:As silly as it sounds if you pull the hose off where it goes into the chassis at the front does the fuel still flow freely as when you cleaned the gauze. It may be blocked in the tap or the gauze may be buggered.

Hey mate. Thoroughly cleaned all the gauze in the pencil filter and flow is fine now. So that's all good. Tank is clean as are the lines through to the carbie.

I followed your suggestion Joel, and you're a legend! There was, indeed, gunk in the idle jet. Sticking out of one of the four holes around the outside (as opposed to the small one at the end) was a piece of wire/leaf/something narrow and thin about 2.5mm long! So I pulled that, forced carbie cleaner in at pressure and made sure all five holes were running smoothly. Fired some cleaner in to every opening on the carbie I could find, from the fuel inlet down.

So I'm now thinking I have a carbie issue as a result of the dirty fuel. If there was gunk in the idle jet, dollars to doughnuts there's more throughout. She's still choking after running for a while. Took her for a few tests today. If I'm doing 60kph or more then she chokes up and dies after about 5 mins run. If I stay under 30 then she'll run (a little roughly though) for maybe 20 mins. I then need to sit with the car for 5 mins or so letting the fuel pump work with the engine off and then she starts up right away. The longer I sit, the neater the start.

So I'm now thinking I might have a problem with the float needle valve or similar and basically the carbie is clogged and running dry. That would seem to account for the different drive times at different speeds? Does that sound likely do you think? I tried the tapping on the top of the carbie thing but it doesn't seem to have worked. Any tips, or should I just buy a kit and disassemble/reassemble the carbie? I have the Haynes manual and the 'How to keep your Volkswagen alive' book. It looks a complex procedure. Whaddaya reckon - should I give it a go? What are a newbie like myself's chances of not stuffing it completely? Is it a job best left to the pros?

I have to say, frustrating as this all is I'm really enjoying getting to know my car better.

Joel Now containing 100\% E-Wang

9,368 posts · joined Feb 2006 · 3 Jan 2009, 8:26 pm

#687164

given what happened when you flushed out the tank the fuel bowl in the carby would have all sorts of crap floating around in it
have you pulled the top off the carby yet?

when it dies on you does it smell really strong of fuel?
there could be crap lodged in the inlet needle holding it open and flooding it
or by the same token there could be crap floating around the bowl getting sucked into the main jet and starving it of fuel

ignition and fuel problems can be hard to diagnose over the net

5 screws hold down the carby top and the return spring
with that off you can remove the float and see how much crud is in the bottom

what sort of filter did you use?
im guessing by the fact you can see that its half full its a clear plastic one
those are only rock catchers, the finer stuff that gets thro them is what blocks the jets
and yes its normal for them not to be completely full but it should do the job for now

i've been using metal EFI fuel filters for a while now
they cost abit more but they filter for a much higher demanding system and for intervals of upto 30,000kms

greedy53 Bishop of Volkswagenism

3,062 posts · joined Mar 2006 · 4 Jan 2009, 8:27 am

#687197

sounds like a dirty filter to me so pull the hose of the pump and see if t still runs out freely if thats ok than check the fuel pump if you have the screw on top there is a filter in there than pull the carby top off and see if any water is in there
you didn't say if you let the fuel run through the hose after the water clean .it really sounds like a blockage and when you get it running empty a bottle of metho in a full tank,i know sounds crazy but it will attach it self to water ,also cross plug leads 1 and 3 so it will pop back through the carby and old trick for cleaning the crap out of jets

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paladin Slammed & Awesome Dubber

79 posts · joined Jan 2009 · 5 Jan 2009, 7:05 pm

#687491

Hey all. Just thought I'd post a quick update. This seems solved for now. After a good clean of the fuel pump and another clean of the exterior of the carbie and what I could get at she's running now. Idling a bit rough, but running and not choking. I think I'll strip and do the carbie just so I know it's clear of gunk. The float chamber had some scale at the bottom of it, so I reckon a good work over is in order.

I tried the metho thing too 🙂

Thanks heaps for all the help!!