o.k here's the deal, stock 16 running a pair of 32-34 pdsit's off a 16 t3 and a 009 for what it's worth and it's in a '70 t2, engine starts well hot/cold and returns good mpg, occasional carb cough, but liveable with.
suddenly engine would not tick-over, it started great and drove fine, just would not tickover, anyway after not really doing anything just re-balance carbs, now ticks-over.
the problem is slightly lumpy response just above tickover while pulling off and an apparent decrease in torque on pulling off, to joe bloggs (john doe) it's running fine, but to me somethings different, it could be the usual paranoia after an initial problem, i just would like some experienced opinions please.
in mitigation to the problem the engine still starts fine and drives smooth and ticks-over nicely it just doesn't seem as smooth as it was before on a standing still pull off, it will pull acceptably smooth in all gears from low speed (15-20 mph), this is unchanged from before problem (if there is one, except in my head)
i have:
checked cut-off valves (o.k)
checked leaks on carbs/manifolds (o.k)
checked accelerator pumps on carbs (o.k)
corrected valve clearences (o.k)
checked spark plugs (o.k)
renewed points (o.k)
re-timed engine (max adv not exceeding 30 at max revs, idling somewhere between 5-10)
on idle i get occasional pops from the exhaust and occasional coughs through the carbs on pulling off.
it seems like a de-synchronisation on fuel delivery from the accelerator pumps, but i've checked they work and visually appear to deliver the same amount, any takers.
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'70 panel
[This message has been edited by stagger lee (edited 06-04-2001).]
engine diagnosis
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Martin in Toronto
engine diagnosis
The backfiring is caused by too lean a mixture. At idle it's usually caused by the manifold sucking in air (that's when the vacuum is at its highest). That's also probably why it won't idle.