Sweet as a nut MK2 - sudden loss of power on steep hill

[WillGT21985]

Hi Scirocco Register!

My name is Will, and in January of this year I was lucky enough to find a lovely K reg GT2. The car was sold on here, and has Scirocco Reg stickers in the windows so I thought I'd come here for some advice.

Brief background: used as daily driver, never missed a beat, Weber carb, just been to Wales and back (300+ round trip), fluid levels fine, never overheated, timing always bob on, engine feels powerful and energetic, described as "sweet as a nut" by RAC patrolman today.

Problem: the car severely lossed power when nearing the top of a hill today - juddering, rapid decline in revs. I managed to get to the top, and pulled off the road to ring for assistance as I was concerned to carry on. RAC came out, checked it, and followed me home, and it ran perfectly.

Could this signify a failing petrol pump, or a faulty fuel line? I imagine these components work hardest when on a steep incline so maybe the first places where the components show a weakness before failing entirely. Is it worth me taking it to my garage (a trusted place) and explaining what happened, so I can nip the problem in the bud? Or is it too hard to nail down what it is yet, as the fault has only occured once?

Many thanks for any advice offered. Cheers!

[mr.brown]

Most likely crap in the fuel tank/line/pump/carb.

Start from the back and take a peek in the tank with a torch - you will also get to inspect the fuel pick-up/sender unit. Check/change the fuel filter. Maybe blow out the fuel lines with compressed air. Remove and clean the jets from the carb.

Once you've done all that you'll probably find it was something electrical

Pump is on the front of the block - but that is unlikely to be the issue as it is mechanical and if it was going to fail it would fail - and not get better a few minutes later.

[unknownmale]

Could also be the needle sticking in the seat (In the carb bowl) this would stop the flow of fuel into the bowl.

[scrappy1382]

check the rubber flange the carb sits on, you may find it is cracked and adding more air than it should. £25 ish to fix and should sort this issue

[the edmundator]

I had a faulty ignition module that cause the same kind of symptoms once as well.

[WillGT21985]

Thanks for these. I'm not confident enough to go fiddling inside the carb, so I'll probably tell these possibilities to the trusted mechanic and let him explore. I'd be fine doing this if I was shown beforehand, but just going by descriptions I'd be worried of doing something wrong to the detriment of the car. Cheers, and keep 'em coming if there are other possibilities.

[unknownmale]

You should say where you're based, someone here maybe close and able to help

[WillGT21985]

I'm in Stoke, cheers.

[whiteshark]

Mr Browns and Eds advice are spot on. Start from the rear and look at your fuel filler neck first for holes and work your way to the the carb. You may have a fuel pipe somewhere that is deteriorating on the inside and closes under pressure. Uphill struggle . If carb model check the flange behind the fuel pump. Really sounds you have dirt in the fuel tank somewhere as the dirt has gone backwards and blocked something due to the tilt. Start it at night in the dark with the bonnet open to ensure there is no arcing on any of the HT leads. Don't give up, I know from experience that your car runs smoothly in the driveway even under high revs, give it a tilt and it can all go Pete a Tong. I'm not a carb specialist and if that goes wrong I get a second opinion, my mechanic!

[WillGT21985]

I decided to test it when driving home from work today. Up a gradual hill I accelerated from 4th to 5th, and then put my foot down again...sure enough, it started to protest, and resist. It's only done it twice - but both times I was accelerating up a hill in 5th.

Does this clarify anything that has already been said?

Thanks for all the points. I've booked it in to my mechanic on Thursday, so he can investigate further. I shall mention some of these points to him.

One more thing I should add...when I bought the car, the chap said that he thought the fuel filler neck was corroding, and would need replacing soon. I've had a couple of other, more pressing, things to do on it since purchase, but I'm now thinking this one is perhaps coming back to bite me in the arse!

Cheers for your help, and keeping it coming.

[WillGT21985]

I've just realised that finding a replacement fuel filler neck can be very hard, judging by past forum posts. Is it still hard? Can a similar part for another vehicle be used instead?

[mr.brown]

Essextom on here is currently producing a batch of stainless steel filler necks.

[WillGT21985]

That's good news. I've just purchased the brass parcel shelf supports from him.

[Village Idiots]

It is possible to modify Mk1 Golf filler necks. The top bit where the filler cap is is different, often this is re-useable from your original. Just cut off the sound bit, cut some off the top of the Mk1 neck and weld the two together.

[mark1gls]

When you take the fuel filler cap off shine a torch down there, you should be able to see if any bad rusty holes as they always rot at that end of the filler neck.