Which unit do I need to get

[rocco1504]

Hi

I have an '85 T3, 1.9 DG, with a Pierburg 2E3 Carb, and it's always had a starting problem from cold and I've been told by a knowledgeable member from here who's done some work on my van before that I need a Vacuum advance unit.

The problem is, I'm not sure which one I need, and one of them, I'm not sure if Brickwerks still list although the page still comes up from my favourites list.

The two items are :- https://www.brickwerks.co.uk/t3-parts/t ... g-2e3.html" onclick="window.open(this.href);return false;
and the other which I say I'm not sure they list is https://www.brickwerks.co.uk/t3-vacuum- ... it-dg.html" onclick="window.open(this.href);return false;

I know sense says it should be the second one, but will the first one do if I can't get the other ?.

Thanks for looking

[CovKid]

First one (if its for the carb). The second one is a vacuum unit for the distributor.

[CJH]

The first one operates the second choke, i.e. it opens the second venturi under full throttle. I don't think that can be the one you've been advised to get to solve a cold starting issue.

The second one controls the vacuum advance on the distributor, so will affect engine performance whatever the engine temperature. If your existing one is leaking you'll particularly notice a problem at higher rpm, so again I'd be surprised if this is what's needed to fix purely a cold starting problem, but if you've been advised to get a new vacuum advance unit then this is the one.

There's a third vacuum unit. It's the choke pull down unit. This is designed to open the choke flap a fraction once the engine has started, to avoid flooding. This is the unit that's most likely to be behind your cold running issue I'd have thought. If the choke flap stays closed until the engine warms up then you'll have an over rich mixture during that period.

But I don't think any of these will be the cause of a colt *starting* issue - check that the choke flap is closed when the engine is cold, and check that the fast idle mechanism is operating properly. If the choke flap doesn't seem to be operating as expected you may have a broken linkage - see here.

[rocco1504]

Many Thanks for the replies guys.

I have to admit, I really don't know much about Carbs or how they work other than supplying metered amounts fuel for running.

My starting procedure consists of one press of the pedal and then turn the key, in the winter it can take 5 minutes to get it running, and it starts momentarily then stops, repeat until it stays running, it's the same in the summer, it just takes less time to get it to stay running; when it starts it sounds like it's going to cut out again, then catches and stays running.

I've changed the fuel pump, fuel filter, but haven't done anything else.

Thanks Again

[CJH]

That does sound like the choke. The choke richens the mixture by closing a flap to restrict airflow. This flap opens as the engine warms up through a combination of an electric heater coil and coolant temperature. My guess is that your choke flap isn't closing, either through poor adjustment or a broken linkage.

You can investigate by removing the pancake on top of the carb - you should be able to see whether the choke flap is closed when the engine's cold. It should be fully open once the engine is up to temperature. If you try to move the flap it should resist due to a linkage that connects it to various springs. If there's no resistance, and you are able to put the choke flap in any position you choose, or perhaps it's jammed open, then you probably have a broken plastic linkage.

It's also possible that your fast idle mechanism needs attention - this mechanism is supposed to override the idle screw to increase the throttle opening while the engine is cold, and as the engine warms up this mechanism gradually reduces the throttle until the idle adjustment screw takes over.

There's a fair bit of description of the adjustments in the latter half of that 'Pierburg 2E3 Choke' thread that I linked to earlier.