Automatic Enrichment Device XJ6

Jun 18, 2008 5 Replies

I have a 1973 XJ6 with a broken AED unit. This means the car is difficult to start from cold. My local mechanic insists that the AED is a disaster guilty of many engine break-downs in the old days. So, to rectify my problem he did not recommend the installation of a new AED unit - although these are still available - but simply bypassed the old one with a valve that one has to open and shut manually: When starting from cold, open valve; when engine is warmer, close valve so that the carburettors constantly get the right amount of fuel. However, this "fix" is far from perfect. The car is still difficult to start when cold and the engine runs very roughly and unevenly until it is warm.



I am no expert on this so views are very welcome. Do you agree with my mechanic that the AED unit is total crap that should be avoided at any cost? Or should I rather install a new AED unit and hope for the best?


Øyvind Olsholt skrev:

No comments on this? Anybody who owns a Series 1 XJ here? If so, what are your experiences with this choke system?

Can't answer your question, but try doing a search here...

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Choose "XJ(S1/2/3 + XJ12)" archive and "AED" as a Keyword, and click "Search"; click on the small white postage envelope (to the right of the "View Entry" button") in any interesting result to see the whole thread of postings for that hit. For example, clicking the envelope on the first entry yields this result...
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WayneC skrev:

OK, thanks. Jag-lovers is a great resource. I can see here that many owners have had trouble with their AED unit. One of the posters on the Jag-lover's forum sums it up quite nicely when he says that the AED is "an expensive item prone to overfueling engine if not in tip top condition". And that's the answer to my question, I guess. So it's up to me whether I choose to stay with the semi-manual solution, or buy an expensive and less than reliable automatic enrichment device.

AED my ass! What you are talking about is nothing more than an automatic choke. Remember the choke? Your mechanic is doing nothing more than suggesting you take out the electronically controlled automatic one and replace it with a manual set-up. In theory he is correct and if he can fashion one, he is a good mechanic. In real practice, you are better off finding a new one and installing it. The problem with his suggestion is, if you install a mechanical choke, the computer system won't be able to deal with it and change all kind of settings (making them almost all wrong) and that would open a whole new can of worms. Dammit!!!, why couldn't they just leave things alone and rely on real mechanical knowledge and engineering?????

Kestrel skrev:

Now, if you remember this is a 1973 XJ6 so there is no computer system to bother about. But I'm inclined to buy a new AED anyway, as you suggest, just to be able to start the damn thing from cold without putting the engine through five minutes of rough idle and cylinders coughing away! The car does start with the mechanical choke but this is no real substitute for a working AED. With the AED the engine starts just as easily from cold as from warm.

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