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Title: Crackle and Pop - thankfully not Snap, Post by: Paul Johnson on 13 July, 2020, 08:23:00 PM Enjoyed a run out this afternoon and the misfire on my S2 never seems to go away. It definitely lessens as she warms up, but should I be worried? Always when coasting - letting off the throttle, but also under gentle acceleration.
New plugs fitted very recently. Thoughts appreciated. Title: Re: Crackle and Pop - thankfully not Snap, Post by: nistri on 14 July, 2020, 01:39:14 PM Did you check the ignition timing? Andrea
Title: Re: Crackle and Pop - thankfully not Snap, Post by: Paul Johnson on 14 July, 2020, 07:24:18 PM Nope. Probably beyond me, but willing to learn.
Title: Re: Crackle and Pop - thankfully not Snap, Post by: SanRemo78 on 14 July, 2020, 08:20:23 PM Do Fulvia distributors have bob weights to advance the timing? Possibly seized or weak springs?
Guy Title: Re: Crackle and Pop - thankfully not Snap, Post by: Mikenoangelo on 14 July, 2020, 08:27:30 PM If the distributor has a vacuum advance I'd suspect that. On light throttle or on the over-run the vaccuum advance mechanism should advance the ignition (this is when the vaccuum in the manifold is at its greatest). If it does not then under those conditions the ignition is too far retarded to properly fire the restricted amount of air/fuel mix some of which escapes into the exhaust and pops and bangs resulting in the symptoms you describe. Make sure the pipe connecting the vaccuum advance to the inlet manifold is sound. If it is then possibly the vaccuum actuator on the distributor is faulty. I've not tried this but if you had an ignition strobe light to watch how the spark related to the timing marks on the flywheel or the fan pulley, youa could try nipping the rubber vaccuum pipe to see whether the timing changes.
Mike Title: Re: Crackle and Pop - thankfully not Snap, Post by: nistri on 15 July, 2020, 07:16:08 AM The distributor does have bobweights (that rarely go wrong). I suggest to read the Fulvia manual for checking the ignition timing: this is often out and also changed by the points wear. Andrea
Title: Re: Crackle and Pop - thankfully not Snap, Post by: lancialulu on 15 July, 2020, 07:35:07 AM If the distributor has a vacuum advance I'd suspect that. On light throttle or on the over-run the vaccuum advance mechanism should advance the ignition (this is when the vaccuum in the Fulvia Distributors do not have vacuum advance.After checking the timing you might have some issue with blocked idle jet especially if the car has been standing for a long period of years before being used. The pilot jets are accessible under the small cover on top of each carburettor. They are the shorter of the jets (2 per carb). Title: Re: Crackle and Pop - thankfully not Snap, Post by: davidwheeler on 18 July, 2020, 08:52:16 PM You will find elsewhere reference to the "idler"/"slow running" jets and advice to increase the size to cope with the higher viscosity of modern petrols. For instance http://www.lancia.myzen.co.uk/forum/index.php?topic=10197.0
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