Whats what here then?

My car started out as a GTI, somewhere over the years its been turned into a carb with bits mixed and matched all over the place.

The sender under the rear seats was a GTI one I think with a pump on it?

Ive taken that out and put in the one out of the donor car Ive got along with the wiring loom.

The thing is, now I'm not getting fuel up front where it counts. If I suck the lines nothing comes through, If I blow them I can hear the fuel in the tank bubbling? Also when blowing one line air seems to be coming out of both of them at the other end.

All in all I dont know what I should have and shouldnt have and Ive got a car thats got no fuel.

hatchback or cabby? And if cabby, what year?

cabby 86.

I was under the impression that the fuel pump is on the front of the engine and that it doesn't have any more with it being carb, what gets me though is the fact fuel cant be drawn from the tank but bubbles when blown.

afaik the fuel lines on carby go from pump all the way to the sender in the top of the tank. if it used to be a gti the fuel lines come from the bottom corner of the tank at the bottom, but there is also a fuel pump there and other gubbins around the tank area

rubjonny said

afaik the fuel lines on carby go from pump all the way to the sender in the top of the tank. if it used to be a gti the fuel lines come from the bottom corner of the tank at the bottom, but there is also a fuel pump there and other gubbins around the tank area

Its an 1986 though - AFAIK a 1986 GTI cabby will have a bolt in tank, a lift pump and a second (high pressure) pump in the same position as hatchback GTIs, next to the tank on the offside.

I know that pre-1985 carb cabbys just have a sender/fitting at the top which the fuel lines go onto (send and return), and the mech fuel pump sucks the fuel from this all okay.

I don't know 100% sure if a 1985 on cabby has the lift pump or not, I think it does though? I think its due to the shape of the bolt in tank

The GTI hatchback and the pre-1985 GTI cabby are the only ones which have a side outlet on the fuel tank. So there's 3 types of tank:

pre-1985 cabby GTI and hatchback GTI. tank held in with straps, 45 litres
pre-1985 (hatchback and cabby) carburettor. Tank held in with straps, 45 litres.
1985- cabby (all, eg carb (eg Clipper*) and GTI). Tank is bolted in, 55 litres.


* Not all 1985 on cabbys which had carbs are Clippers, there's GL too. And some Clippers had injection engines.

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So would it be easier to change the tank and lines? ive already put the sender in but it just wont pick the fuel up but like I said when you blow it, it bubbles in the tank. So that must mean both the pickup and lines are going right into the fuel and tank, its just not sending it up front.

nath69uk said

So would it be easier to change the tank and lines? ive already put the sender in but it just wont pick the fuel up but like I said when you blow it, it bubbles in the tank. So that must mean both the pickup and lines are going right into the fuel and tank, its just not sending it up front.

Sorry, that doesn't make any sense to me. Yours started out as a GTI - it should have 2 fuel pumps, one in the tank and one next to it.

A carb car after 1985 (can someone confirm properly its fuel tank arrangement) has an in-tank pump and a mechanical pump on the engine. A carb car before 1985 has just one pump, the mechanical one on the engine which is able to suck fuel from the tank.

The fact that yours isn't able to suck fuel might be because:

1.  the tank is different, though I can't see this as an issue. although VW did choose to fit an in-tank pump after 85????
2. there's something wrong with the fuel lines, eg there's deterioration in the rubber pipework which causes an air leak, which means the mech pump just sucks air instead of fuel.

I suspect its (2), also because yours started as a GTI but now has a carb engine (why????) then who knows what the guy who did it, did with the fuel lines. Also why didn't he replace like-for-like? What is the reason for replacing a fuel injection engine with a carb engine? You have to wonder if they're of the mindset to replace FI for carb, maybe they didn't fully understand the fuel lines and pumps etc too?

Does it have the wiring for an in-tank pump (it will have 4 electrical connections at the fuel gauge sender, if its just the fuel gauge alone it will have 2 connections).

yeah the later cab injection does have a lift pump in the tank, but my point was the lines to the front of the car come from the bottom corner of the tank where the main pump is, i wasnt really clear about that though. The reservoir, accumulator and lift pump bits may or may not still be there though, depending what was done.

What I was trying to do was figure out exactly what was done to convert it to a carb, before we go chasing our tails.  If it was converted properly both the main and under car pumps should have been removed and a carb fuel level sensor dropped in the tank, the lines from that then go directly to the fuel pump on the front of the block.

The main pump almost certainly was removed, cant beleive a carby pump could suck fuel thru a deactivated main pump. If it was still there and running, the carb would be completly flooded!

One way they might have done it is leave the lift pump and reservoir in, then plumb that to the carb. I've heard some have done this with their bike carb setup, so I guess it could work.

But this is all theory and guessing, the OP is going to have to get underneath and check exactly whats going on, plus look under the metal plate under rear seat to see if its a fuel lift pump or just a level assembly thats fitted.

The car has been converted for reasons unknown to me. the car ran fine when I got it, however all the wiring was a mess and to be fair beyond repair. I've taken the whole original wiring loom out and replaced it with the loom taken from the H reg carb.

The fuel sender under the seat did have a motor attatched to it, I've replaced it with the one from the H reg carb.

As for the fuel lines being perished, if that was the case then when blowing down the line it would also leak air and not create bubbles in the tank.

I was hoping there was an easy explanation to this, looks like I'll have to get on my back after all.

Thanks
guys.

nath69uk said

As for the fuel lines being perished, if that was the case then when blowing down the line it would also leak air and not create bubbles in the tank.

Not necessarily!

Hmmmm, like I said I was hoping to get a simple reason for it. Looks like I will have to go and investigate tonight.

Thanks.

ok then, as paul says have a shufti at your fuel lines.  could be they've gone inside and are acting like a non-return valve, you can blow but you cant suck
i take it the fuel filter was replaced?  could be pump is weak also.  If it still had the lifter pump fitted then maybe it was wired in to fill the reservoir under the car, then the lines went from there to the pump on the front of the block. if the under car reservoir is still fitted this could explain it, as engine pump probably wont be able to suck fuel from inside the tank once the reservoir is empty…

Done it, found a small square thing on the drivers side up near the tank. Probably a pump of some kind. So that was it I ripped the whole lot out and replaced it with straight lines from the sender to the engine. Dropped some fuel in the carb and cranked it up, wasn't long until the fuel was drawn up into the lump all by its self.

sorted

Thanks for the help fella.