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Yet another Pierburg 2E3 question

Hi everybody! Just when you thought you had gotten rid of annoying 2E3 questions, here I come and throw one more: I just bought an Opel Kadett 1.3S, 1990. Very similar to Vauxhall Astra, from what I've been told. Anyway, it features a Pierburg 2E3 carburettor, and here's my problem: Assume the engine is cold (has been left out for 10 hours at -10C, i.e. really cold). Starts-up nicely, at first try. Idles at high speed for 3 seconds and then the idle becomes 'lumpy', as if the mixture were too rich (but that's just a guess, I can't check the mixture). Depending on temperature and engine speed, this problem disappears after 10 mins. To be more accurate, it goes away when the water temperature gauge reaches the blue marking on the scale -beforehand it stays far in the un-measurable range, the needle goes as low as mechanically allowed to-. If I attempt any driving during this period, the car feels lumpy and has almost no power. Still, the engine shows no sign of trying to stall, it runs stable (within the above-specified problem limits). To give you some idea on the temporal sequence of problems under my bonnet, I'll try to summarize it below:

Cold engine start: 'bumpy' idle, ----lumpy driving;

10 mins after: fast, stable idle ----lumpy driving; 20 mins after: fast, stable idle ----stable driving; Then: the fast idle goes away by depressing the throttle once or twice. Then: everything runs just fine. Low idle, good response. No 'but's.

The sparkplugs are new and the ignition is electronic. HT wires in good condition, under my own inspection. One more weird thing, the hot/cold air flap valve in the air cleaner spout is present and in good working condition. But it is not attached to anything (no vacuum hoses or thermostatic gadgets). It revolves around an axle and is brought back to a stop by a spring. I don't know who or what controls it. Again, Haynes manual is misleading, they point out some vacuum hoses. I have no hoses there and no hole in the air cleaner body to attach them. The only hose attaches to the air cleaner just near the carb body and is termed: 'Air cleaner hose connection', in the Haynes manual.

Please help me identify the problem. Had already spent some 30 euros on Haynes manual, but they seem to be addicted to replacing (or disassebling) the part, rather than repairing it. No good hints in there.

Thank you.

Matei

Reply to
Matei Rusu
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Basically as soon as the engine fires the choke flap should unload slightly, if this does not happen then you get your symptoms. To check: remove the air cleaner so you can see in the top of the carb, start the engine and have a look (you may need an assistant) when the lumpy idle begins the flap should have already opened a little, it probably hasn't, push the flap slightly open with a finger, the idle should improve. There is probably a vacuum operated diaphragm which is meant to open the flap as soon as engine starts, this may have a split supply hose or may just have failed, to test diaphragms you need a source of vacuum.

MrCheerful

Reply to
MrCheerful

Sounds like the choke pull down diaphram isnt working as it should and is over choking the engine at cold start.

Tim..

Reply to
Tim (Remove NOSPAM.

Thanks for the advice. I'll give it a try this week-end and I'll keep you informed on my progress. Best regards, Matei

Reply to
Matei Rusu

...wasn't the autochoke on this model of Astra troublesome after a few years old?

Reply to
Sean

The last five words in your question are superfluous, ime. I don't think the Pierburg carb in my old Cavalier ever worked all that well (and I knew the previous owner). I should have junked it for a drop-in Weber replacement instead of suffering years of cursing and swearing, and all the symptoms the OP described.

Reply to
John Laird

No. Well yes, the autochokes were abit trouble some on VX's but it was usually the GM varajet carb that had the problems, not the Pierburg.

Strangely, this exact problem is fairly common on the smaller VW's with the Pierburg 2Ex carb when they work perfectly fine on Vx's....

Tim..

Reply to
Tim (Remove NOSPAM.

Thanks for the help guys! The cause for all these problems seemed to be the choke pull-back unit. Namely, the vacuum hose providing vacuum to this mind boggling unit (whatever it does there, it's beyond human mind's comprehension limits). The hose feels spongy and has a lot of small cracks in it. As Mr. Cheerful and Tim said, pushing the choke flap up a teensy bit (by finger) with engine running returned the idle to its normal state. Now there comes a really stupid one: how do I take the hose out of the wonderful choke pull back unit? It seems to go inside its case, and slightly pushing and pulling it did not move the thing at all. Should I dismantle the pull-back unit? Any hints on it? As usual, nothing in the Haynes manual about that. Moreover, the hose attaches to the carb body in a misterious way. It simply goes to the carb body. No rings or retaining screws. I could yank it out, but what about putting the new one back? Just push? The vision of the joint is somewhat hindered by the whole carb body, so I have to rely on my sense-of-touch. So the "refer to figure" advices in the Haynes' are not very useful. Any hints would be highly appreciated. Thanks again. Matei

Reply to
Matei Rusu

Vacuum hoses usually just push on - the vacuum keeps the hoses firmly attached. The decomposing rubber hose has probably just stuck to the metal tube it attaches to - give it a firm pull and twist and it should come free.

Reply to
Bob Davis

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