Starting Issues & Leaky Fuel Lines

[DaveVR 0]

Hi all,

 

Had an issue with the VR recently whereby it starts on the button first thing but after a decent run and being left for a while it spins over for far too long and struggles to start, appearing to suffer from from fuel starvation. When it eventually fires it struggles to pick up revs/misses for a second or two then is spot on from then on. It did this yesterday on leaving retro rides gathering and when it did fire, it stunk of fuel. Popped the bonnet and found the fuel line onto the rail leaking at the clip where i noticed it is splitting. As it warmed up it stopped leaking (probably making a seal when expanded). It looks a bit knackered as though somebody has chopped it down in the past to stop the same issue so either way it needs new. My two questions are;

 

1. Is there anywhere I can still buy genuine under bonnet fuel lines (bulkhead to rail) - did a search on here but seemed to be people mostly asking about aftermarket stuff?

 

2. Can the starting and the leaky line be linked? I've been trying to work it out and all I can come up with is that it may be struggling to build up pressure. It's a strange one because it never does this from cold, is fine when running and when putting my foot down?

 

TIA, Dave.

Edited August 20, 2018 by DaveVR

[Jim Bowen 1]

The fuel hose is just an 8mm ID fuel hose, not much point getting it from VW, they will just be buying it in and overcharging for it.

 

I'd like to say that will be causing the fault but i've had the same issue before (leaking fuel when cold and the struggle to start when hot) and replacing all the fuel lines didn't fix it. I am starting to wonder if its pump related as i've changed everything else.

[DaveVR 0]

Thanks for the info Jim. It was more hope than anything that the issues are related but like you say, it does seem like a supply/pressure issue. It's just strange that it only does it in those circumstances.

[Bauhaus 3]

I don't have a VR but on a G60 this is usually caused high under bonnet temps that build up when you stop after a good run, the heat cooks the fuel in the lines and a vapour lock occurs in the fuel line, upon start up the fuel pump pushes the vapour lock out which is the struggling/misfires your experiencing.

 

If your getting new fuel pipe make sure is for fuel injection and is R9 rated hose.

[fendervg 32]

Both feed and return hoses were still available from VW a couple of years back when I replaced mine. As said above, you can use any fuel hose of the correct diameter once it correctly rated for pressure and purpose, it's not a high pressure system anyway with the pump rated at 4 bar. The advantage of using the OEM one is that it is pre-shaped to fit - some people go for braided, but there's no advantage really except for looks.

 

Another trick is to simply cut a section off the end if you have enough left and re-attach for a clean fit, but it sounds like that may have happened already on yours. Getting the ends and the hose clips on to the solid pipes near the bulkhead can be tricky as it's a tight fit - soaking the ends in hot water or some fuel to lubricate them will help.

[DaveVR 0]

Thanks Bauhaus, the theory on this sounds about right. As I say, it's not necessarily a 'hot start' issue. The car was parked up in the show grounds at about 9:30am and we left at around 12:30-1pm so not hot at all but not enough time to cool to stone cold with the current weather. The car often gets left in the garage for months at a time without starting and when I come to start it, it spins over maybe three times and fire up no problem so it definitely doesn't smack of a supply issue to me.

[DaveVR 0]

Both feed and return hoses were still available from VW a couple of years back when I replaced mine. As said above, you can use any fuel hose of the correct diameter once it correctly rated for pressure and purpose, it's not a high pressure system anyway with the pump rated at 4 bar. The advantage of using the OEM one is that it is pre-shaped to fit - some people go for braided, but there's no advantage really except for looks.

 

Another trick is to simply cut a section off the end if you have enough left and re-attach for a clean fit, but it sounds like that may have happened already on yours. Getting the ends and the hose clips on to the solid pipes near the bulkhead can be tricky as it's a tight fit - soaking the ends in hot water or some fuel to lubricate them will help.

 

Thanks fendervg, yep theyve been shortened already so time for a replacement. Depending on cost, if they're still available I may go for this due to the pre-shaping (looks better imo).

[Jim Bowen 1]

Try and give the relays a clean up. I think they can be opened up

[Kezbo 0]

I bought those fuel lines from Heritage Parts recently, genuine VAG ones. Not cheap though.

 

Interestingly I have the opposite problem, takes ages to fire from cold but starts on the button when warm.

[a_riot 0]

I bought those fuel lines from Heritage Parts recently, genuine VAG ones. Not cheap though.

 

Interestingly I have the opposite problem, takes ages to fire from cold but starts on the button when warm.

 

Might be your fuel check valve at the fuel pump. Its supposed to keep the fuel from going back into the tank when the fuel pump isn't running, and so if leaking, typically cold starts are long, warm starts are short.

[DaveVR 0]

I bought those fuel lines from Heritage Parts recently, genuine VAG ones. Not cheap though.

 

Interestingly I have the opposite problem, takes ages to fire from cold but starts on the button when warm.

 

How recently did you buy them Kezbo? I had a look on the website and couldn't find them, even in the out of stock section.