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Audi 80 lumpy idling - Steve Bailey
My 1986 Audi 80 1.6 petrol (Pierburg 2E2 carburettor with automatic choke)is running well when the engine is under load (i.e. it goes well when you have your foot on the accelerator), and runs well when it is cold (the automatic choke keeps the revs high).

When the engine has warmed up, it still runs well under load, but when it is idling it is very lumpy and occasionally stalls. The lumpiness is erratic, not a misfire on the same cylinder.

My theory is that the idle jet has some muck in it, as when it is cold, or the engine is under load, it ses the main jet.

A few points to note:
I ran out of petrol a couple of weeks ago.
I changed the disposable in line fuel filter.
The timing is correct.
The rotor arm and distribtor cap are new.

What shall I do? Clean the idle jet with something?

Any ideas gratefully received.

Steve
Re: Audi 80 lumpy idling - Pat
Steve,

I'm by no means a technical expert, unlike many on this site, though the symptoms appear similar to those I experienced many years ago with a 1980 VW Jetta with manual choke. It suddenly started stalling when coming to a stop at traffic lights, etc.

I took it to an independent VW garage where they cleaned the idle jet by blowing compressed air through it. A small sliver of wood came out! Must have been in the fuel!

Hope you get the problem sorted.

Pat
Re: Audi 80 lumpy idling - Marcus
You need to check the vacuum pipe which connects the brake servo to the inlet manifold, this can sometimes perish and cause an airleak into the manifold, I had exactly this problem on my sister-in law's Audi 80 automatic a couple of years ago and also on a VW jetta which has the same engine.

Let us know if you solve it !
Re: Audi 80 lumpy idling - Adam Going (Tune-Up Ltd)
Steve,

Marcus is on the ball with servo pipe connection, but also check for air leaks along the inlet manifold gasket. Blocked idle jet very common, as the air corrector entry for the idle circuit is very exposed in the top surface of the carb. Most jet blockages are due to material ingressing on the air side rather than the fuel side - make sure the air filter elemnent is clean and the correct size, clean the filter casing at ever service, and if you car does not already have one consider fitting a filter in the crankcase breather on the underside of the filter casing, as the entry point is inside the ring of the air filter, making crankcase emisssions unfiltered normally.

HTH, Adam
Re: Audi 80 lumpy idling - Richard Hall
Fault repair on Pierburg 2E2 carburettor:

1. Remove air filter.
2. Undo throttle cable, all pipes, cables etc.
3. Undo four bolts securing carburettor to engine.
4. Carefully remove carburettor and place in bin.
5. Fit a Weber (£160ish from German & Swedish).

Seriously, the 2E2 is a very complicated device, and once they start to give trouble, there are so many vacuum and electrically operated devices that fault diagnosis becomes very difficult. The Weber is a splendidly simple device, easy to fit and gives better fuel economy and much improved throttle response. I fitted one to a C reg Audi 80 1.6 and the improvement was well worth paying for.
Re: Audi 80 lumpy idling - David W
Richard,

I was tempted towards advising this expensive(ish) solution.

Interesting that our pocket money Polo has the first 2E2 (or similar) I've known that works as designed at 95,000mls. It behaves as unobtrusively as fuel injection, given the time I've spent looking at/stripping this model of carb I can only wonder when it'll start chugging?

David
Re: Audi 80 lumpy idling - Rob F
DW,

Don't you have the 2E3 on the Polo? Mine does, and once I'd set it up after some overzealous meddling by a previous owner at 100k, it's run perfectly (I think I'm on about 150/160k now - and third speedo). Flange gasket leaking has been the only trouble.

As to the 2E2 - that does deserve to be binned.

Rob F
Re: Audi 80 lumpy idling - David W
Rob,

You're right, it is a 2E3 on our 1.3 Polo. Same basic design as the 2E2 but I think missing just one devilish component...the vacuum operated throttle position device.

Perhaps that is why the Polo is so much better than the last couple of 1.6 VWs I've had to sort with the 2E2.

David
Re: Audi 80 lumpy idling - Richard Hall
Last time I moved house I had a clear out and no fewer than four 2E2s went in the skip.... Strange that the normally methodical Germans could get it so badly wrong.
Re: Audi 80 lumpy idling - Colin Barrow
I've the same carb on a 200k passat estate - check that none of the unused vacuum take off(s) at the base of the carb (and inaccessible unless you take the carb off) haven't got perished rubber bungs on them. If so renew/ replace the bungs. I don't agree with the comments about the 2e2 carb - get hold of the Haynes Solex/ pierburg carb manual and read up about the carb