Weber fuel return

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WreckTangle
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Weber fuel return

Post by WreckTangle » Sun Aug 11, 2019 8:41 pm

I have the seemingly common problem of fuel starvation with an aftermarket Weber carb on my 1.8 GT2 Auto. I’m in the process of implementing the welding tip fix which I think will solve the problem as folding the fuel return pipe over worked as a quick fix to get home. I’m trying to do this “properly”. Renewing the vapour separator made no difference so I have cleaned up the original, tapped the return spigot with an internal thread and slightly modified a welding tip to enable me to attach it to the return outlet. I’m expecting this to work, but I have been mulling over whether replacing the vapour separator with a low pressure bypass fuel regulator might be the “proper” fix since it would maintain consistent fuel pressure into the carb. Has anyone tried this or am I barking up the wrong tree?
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mark1gls
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Re: Weber fuel return

Post by mark1gls » Sun Aug 11, 2019 9:37 pm

I’d try the welding tip 1st and see if that helps...

Let us know how you get on.


Mk1 78 Scirocco GLS 1.6 FR, weekend toy.
Mk1 88 Golf GTi cabriolet 1.8 DX. Daily drive.
Membership No. 323

WreckTangle
Posts: 18
Joined: Sat Dec 02, 2017 6:16 pm
fill in the right answer: 15

Re: Weber fuel return

Post by WreckTangle » Sun Aug 18, 2019 4:34 pm

Early indications are that the welding tip has cured the problem. About 60 trouble-free miles since fitting it taking in some long hills which seemed to bring on the problem before. However, I’m not sure I understand why. As far as I could make out the vapour separator has its own internal restrictor and will only send fuel down the return line if a constant flow of fuel is going through to the carburettor. Does the Weber require greater flow or pressure than the original Pierburg? Is the setup with a welding tip the best way to achieve what it needs?



mark1gls
Posts: 3291
Joined: Thu Apr 02, 2009 9:28 pm
fill in the right answer: 10
Location: Somerset

Re: Weber fuel return

Post by mark1gls » Sun Aug 18, 2019 10:15 pm

The problem seems a bit random, few posts on this problem on Mk1 Golfs as well and like the Scirocco not everyone seems to suffer with it.

Could be the fuel lines have slightly different internal bore size on some cars, fuel filters not letting enough fuel through.... etc...

The welding tip does seem to cure the problem 95% of the time...

Not 100% sure why it works but if it does happy days. :-D


Mk1 78 Scirocco GLS 1.6 FR, weekend toy.
Mk1 88 Golf GTi cabriolet 1.8 DX. Daily drive.
Membership No. 323

kidcrewbob
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Re: Weber fuel return

Post by kidcrewbob » Tue Aug 20, 2019 12:26 pm

Worked for me also - plugged hoses with a couple of appropriately sized bolts to start with and hey presto - runs like a dream. Can only deduce that the fuel return arrangement is just not required on a 1.8 with Weber conversion. Assume it's a Pierberg "feature"!