Mk2 1.6 driver light restoration, starting/vacuum issues, help!

[XTC]

I was wondering about the intermediate shaft because it spins so freely it would be easily knocked, looks like all the auxillery belts and cambelt covers are coming off tomorrow! Let's hope it's that

[Brighouse-gti]

Sounds like timing issue 

[XTC]

Ok reset the timing belt today just to make sure, it is definatley ok.

Set the float level in the carb, checked that the bowl was filling up. Jets were cleaned.

Problem is the same, starts up revs up to 2000 sounding as it should then dies, or runs poorly for a few seconds before dieing.

To confirm it was fuel starvation i dropped fuel in the carb air intake with a syringe a couple of drops every second and it continued to run for 15-20 seconds like this.

Im starting to think the best way to go now is to fully rebuild the carb so if anybody has a rebuild manual for a weber dmtl 32/34 carb it would be a great help?

Also confirmation of the vacuum pipes would be a good, been fighting this problem for 4 weeks now!

[Santiago]

Re. vacuum pipes, what did you change between the first and second posts of the thread?

As far as I know, the hose from point B in your pic isn't required for the Weber, and should be blanked/blocked.
Airbox vac hoses go just from the vacuum diaphragm that moves the warm/cold air blend-flap to the front fitting of the airbox thermostat, and another from the rear fitting of thermostat to back of carb.

Have you checked the order of the leads on the dizzy cap?   1342 clockwise. 

[XTC]

Between the first posts Iv done exactly as you've said, plugged b up and the one on the back of the carb to the air box flap thing, how can I test this flap is working?

Yeah that's the firing order Iv got and Iv got the rotor arm pointing at the notch at tdc cylinder 1, any ideas as what could cause fuel starvation as the engine was sat for almost two years?

[Santiago]

...how can I test this flap is working?

Start up the engine from stone cold, pop the bonnet, then pull the vac hose off the diaphragm above the blend flap.  I'd imagine you should be able to hear it clunk from full warm-air to full cold-air position.  If you can't hear anything happening, remove the foam-covered hose that goes to the wing, and photograph the flap with and without vac hose attached to diaphragm, to see if it moves. 

...any ideas as what could cause fuel starvation as the engine was sat for almost two years?

Is there an inline fuel filter in the bay? If so is it clean-ish?  Trying to work out how the carb got "full of gunk".
Not sure if the Weber has this, but on some carbs there's a teeny-tiny filter inside the fuel feed connection of the carb, maybe this is badly clogged if there is one?

[weazgti]

Have you checked the fuel pump is working ok? Pull pipe off fuel pump and crank engine

[XTC]

With regard to the fuel pump, iv done as you've said and its pumping plenty of fuel out. The carb bowl is filling up its as though the fuel isnt getting through the jets.

 Thanks for explaining, I will try the hot/cold air flap next time i work on the car, is this essential for running?

The fuel filter in the bay is a little dirty, i bought one on the way home from work today and will fit it before i next try to run the car.

Iv been stripping the carb down further than before and found this :




Im not sure exactly what it is, its spring loaded from either side, there is a hole at the bottom of the float bowl that feeds into this chamber then it looks as though it feeds to the jets.

It was corroded as the photo shows and had some more 'gunk' in, does anybody know what its function is?

[Santiago]

... I will try the hot/cold air flap next time i work on the car, is this essential for running?

In a word, no.  Certainly won't be causing your current problem.

The fuel filter in the bay is a little dirty, i bought one on the way home from work today and will fit it before i next try to run the car.

A quick look at google images suggests that there might be an internal fuel filter, so find and clean that out if you haven't yet. I guess it can't be too bad though if the float bowl is filling.

The valve you've found is sometimes called a power valve.  It reduces fuel supply at idle and low throttle openings when there's deep vacuum in the inlet mani, and vice versa.  Corrosion anywhere inside a carb is bad news, so clean, clean, clean.  Idle jets can get blocked by very small bits of crud.

[XTC]

I came across the fuel filter you mentioned whilst cleaning the carb, it was virtually spotless!

I gave the carb the clean of a life time, cleaned all the jets again with an airline. I found that the hole diameter of the Primary main jet didn't look as large as I had expected, soaked it in carb cleaner over night and sprayed again with the airline. In the end I had to resort to poking the bristles of a toothbrush down the hole (I know your not supposed to) and it dislodged some white powder, I think it's the remenance of dried up fuel, blew the jet out again and now the hole is twice the diameter and clear!

That coupled with the corrosion and blocked power valve gives me hope! Il fit the carb tomorrow evening and post the result.