GTII Lurching on Motorway

[nolegjoe]

I've been having a really annoying problem lately, my '92 GTII has been great to me until very recently. I have this intermittent problem specifically on the motorway, where the car begins to lurch on throttle. However, when I came off the motorway, it drove sweet around town. Back onto the motorway, and it's lurching like crazy again. It strikes me as a fuel starvation issue and I've tried to troubleshoot accordingly, but I'm still having the same problem. In fact, the latest mechanic has told me he can't fault the car, but I'm sure the car hasn't fixed itself.

The things I have tried/replaced so far:

Replaced the carb with another Pieburg 2e2
Replaced some rubber fuel hoses
Replaced fuel filter
Replaced spark plugs, HT leads, King lead
Replaced rotor arm and dizzy cap
Replaced ignition coil

The next thing I'm going to try is replacing the vapour separator, I hear that can get bunged up. After that, I'm going to check if there is any rust and shite in my fuel tank. I've also read something about an adjustment to the carb float height may have something to do with it? http://www.clubgti.com/showthread.php?1 ... eeded-ASAP

Anyone have any ideas?

[whiteshark]

Start from the back. Check fuel filler neck. Check fuel tank for dirt. Make sure you have a fuel filter before the carb. Your problem sounds like an old fuel pipe compressing together under pressure. I know you have replaced some of the fuel lines but under pressure some of your old fuel lines will squeeze together under pressure of higher speeds and block enough fuel coming in. I have had similar problems in the past. Be patient and you will eventually find the fault.

[unknownmale]

You can eliminate the vapour separator by running the line from the pump direct to the carb, go for a little run and if it's still doing it then there's no use spending the money on it.

[scrumpyone]

Filler neck bud

[mark1gls]

The rubber flange that the carb sits on? They can split.

[nolegjoe]

These are all really useful answers, and I'll start looking for them when I'm next at my parent's.

Regarding the rubber hoses, are there any before the bonnet, or are they all metal to the tank?

[bengould]

They are rubber from the sender to just under the car, then metal all the way into the engine bay.

Ben.

[nolegjoe]

I guess I'm buying a whole lot of new hose then! Do you know if they are 5mm diameter all the way back, or do they change size at all?

[mark1gls]

Before you start spending money on new fuel hose remove the fuel sender in the tank and have a look in the tank to see it there is dirt etc in there.

The hoses which get often over looked is the one from the fuel sender to the metal fuel lines under the car, it's about 50 cm long and there is 2, one for the fuel out and the other for a fuel return, to change them you can attach your new hose to the old hose and pull it through but be care full not to pull to hard in case you lose the end of the new pipe as it's a pain to get your hands in there. DO LOOK AT THE OTHER THINGS FIRST.

[nolegjoe]

Bad news. I've have a look at the fuel filler neck, and it does indeed look rusty, not bad enough that it's leaking, but it probably isn't far off. I've had a read around the forums and I've started to learn how much of a pain it is to replace. Apparently, you can't get the correct part anywhere. The only options are:

chopping up a Golf MK1 filler neck (which may not work because I have the space saver spare wheel, so my tank is too big?)
Finding an old scirocco at a breakers with a decent filler pipe
Getting hold of a BMW E36 plastic pipe and bending it to fit
making a new pipe entirely out of rubber somehow?

Does anyone have any advice on this? I'm not able to weld or fabricate anything myself, and I don't know anyone who can, so I'd like to avoid the Golf MK1 replacement unless it's the only option. I don't mind paying £150 for the genuine part, if that's what it costs, but there seems to be a lot of confusion about how to get it!

Some please help! Anyone know a VW guy who could fix this for me near Basingstoke? I'm desperate!

[mark1gls]

Shine a torch down the top of the filler neck and look for holes as that's where they usually rust.
There is someone making some filler necks at the moment so you may be in luck. There is a thread on this site about them.

When you replace the filler neck paint and protect it as they usually only come with paint on to stop them rusting.

[nolegjoe]

My hero! I'll look for the post. If you could point me too it, I'd appreciate it.

[mark1gls]

Here you go.
viewtopic.php?f=30&t=18592

Edit. Just noticed you have already found it and posted