Fuel tank sender unit ......**FOUND ONE!!!!**

[WreckTangle]

I hope that works for you.

In my experience, you think you’ve solved the fuel starvation issue and then it comes back to get you when you least expect it. After restricting the return line I used my GT2 1.8 Auto trouble-free for a number of local trips and commuting 25 miles each way all through the depths of lockdown - I work at a hospital. When lockdown was lifted I used it to visit a friend about 40 miles away. It made it there no problem but started playing up on the way back. Mine seemed to be linked to the tank getting below half full. There is no crud at all in my tank and the filler neck and connecting hose is new. My next step will be to replace the Weber with a Pierburg that I’m restoring and which I reassembled last weekend. When I fit the Pierburg I shall use a new carb flange and new vacuum hose. That will help to eliminate some other variables.

Fingers crossed that yours stays fixed.

[kidcrewbob]

So far so good Wrecker - not a blip whatsoever c.150 miles in. That tank half-full thing is something I noticed - I think it's to do with the concentration levels of crud to fuel being increasingly higher and therefore more likely to be sucked up the pipe - also seemed more likely after a hill climb and quick descent with a couple of twisty bends - ie shaking the crud all over the place whereas if your gunning it on the M6 in a straight line the crud will gravitate to the rear of the tank and away fom the pickup......that's my theory !! I too thought I'd shifted all the crud but would say you will never get a fully clean tank without taking it off and blasting it if not replacing it - cost me £112 for the tank and £100 to fit.

[kidcrewbob]

So another 50 flawless miles this sunny day - got to within 500 yards of home only to be caught in 4 way temp traffic lights - so sitting there for 5 mins. Engine running slightly above middle temp according to the gauge which is normal when stationary - slipped it into neutral for a few minutes, lights change off we go - COUGH SPLUTTER & DIE - you m0thrf4cker!!!!! So several hundreds £ on (filler neck, tank, filters, restricted return flow, new fuel lines etc etc) still cannot be trusted - just as you said Wrecker......

That said, I had this effect before (on same road!) when I slipped the auto into nuetral for a few mins rather than ride the torque converter and it seemed to kill it but I don't understand how or why - this is still a fuelling issue but unlike other pre-tank replacement splutters the full-choke-to-get-you-home trick does not work - seems to need to stand in this scenario. Guarantee it will start as if nothing happened in about an hour.

What a nightmare.....

[GT_II]

Is it fair to say it only stalls after the car has been idling for a long while? I know nothing about the Weber carb, but thinking outside the box, is there a possibility the engine is being suddenly flooded with excess fuel on opening the throttle rather than being starved due to a blockage?

Also have a read of "vapor lock" on Wikipedia which might be relevant.

[kidcrewbob]

I guess that is a possibility although I couln't smell fuel wafting from the engine bay and there were no blow-backs / back-fires - whilst waiting for the lights I was on a slight incline to go over a hump back bridge so would have had to give it a quick prod after shoving it in D to get it over - is it possible I have over-restricted the return pipe perhaps.?????

[kidcrewbob]

Great tip - vapor lock symptoms seem very relevant here indeed. Will do some checking.....

[WreckTangle]

It sounds as though your symptoms are very similar to the ones I’m seeing on my 1.8 GTII Auto with Weber carb.

I wondered recently whether I hadn’t restricted the fuel return enough. I used a modified welding tip drilled out to 1mm.

My longer-term approach is to restore a Pierburg and get the car back to as near factory spec as possible. However, that is proving to be quite a slow process.

I went up to my garage today to get the battery out of the Scirocco to charge it and took the opportunity to have a good look at the Weber in the light of the knowledge I’ve obtained working on the Pierburg.

I spotted straight away a couple of problems with mine.

The electric throttle body heater, although present, is not actually making contact with the copper heat exchanger on the Weber. There is a gap of at least 2mm. This is probably leading to icing in certain conditions.

Also, although I cannot really see the rubber seal the carb sits on I can see largish part of a paper gasket protruding from under it. This suggests it might be leaking at times.

I suggest you check for some simple basics like this.

The other thing that is clear is that the vacuum control on the Weber is nowhere near as sophisticated as on the Pierburg. In fact, as far as I can tell, there is no provision for raising the tick over when drive is engaged. This might explain another irritation I’ve experienced running the Weber.

[kidcrewbob]

I did some vapor-lock checks following the last episode and found that the fuel pipe from the swirl pot to the carb was lying across the rocker cover and was getting extremely hot - since tying this pipe up & away from the heat source I've had no issues but will not hang the flags out just yet!!

My rubber seal is fairly new and sound with no sign of leaks etc, however I'm not sure about the throttle body heater / heat exchanger on the Weber - not something I've checked - will have a look to see what's what.....

Interesting observation re the Weber and the auto - I have thought that this setup may be the root cause of slight vibration at standstill when in P or R and maybe the Pierberg would do better but I'm not ready to throw that sort of money at such a minor issue.

Check this guy out if you want to go for a Pierberg replacement - I've not used him but seems very niche expertise :-

https://sites.google.com/site/pierburgc ... rburettors

[mark1gls]

I did re route my rubber fuel lines away from the engine and away for the inlet/exhaust manifold as I was worried about the heat for the engine.

[C 20 CCO]

Back in 2018 I had terrible problems with fuel delivery. I logged it on here so it’s archived. Turned out to be the inlet manifold gasket. The suction for the fuel to reach the carb is but a weak breath. The slightest breach and the fuel flow can’t keep up with demand....

[C 20 CCO]

Just an after thought on replacing the fuel sender in the tank. Rub a liberal amount of graphite from a pencil around the rubber seal to lubricate it. Old plumbers trick [emoji106][emoji106]


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[RussGLAuto]

Just read your posts, interesting. I'm in exactly the same predicament.

How did the new tank fitment go? About to have mine replaced. Any issues you had?

Cheers

[C 20 CCO]

Hope it went well[emoji106]

[RussGLAuto]

Just got her back yesterday, new tank & fuel lines installed.
Surprisingly, the main rust culprit was the fuel lines themselves, almost looked like furred arteries!
With the jets in Pierburg blown through, new filter she is now purring like a good un!
The lads at Peterborough Classic & Customs did an amazing job, didn't damage the original sender unit, but I have a nice new old stock spare now for the future just in case .

In summary, Pierburg refurb is most defiantly the way forward over the Webber. As nature intended!

[mark1gls]

Glad you have the car back all working now, it can be a pain finding and sorting out intermittent running problems.