D
Dave T Scotland
Hello ,
Sorry this is so long, but I've spent a long time tying down the
problem & might as well give the detail to cut down the field a bit....
I have an almost perfect 1986 Astra L 1.6 petrol; OHV 16SV with 2E3
carb & Siemens MZV BY ignition module. 20 years old but only 29,000
miles genuine and almost 100% rust-free.
Brilliant - BUT I have one engine problem that's driving me nuts, and
I need fresh ideas please from anyone who can still remember cars with
carburettors!!
As background, the car has been immaculately looked after and serviced
according to the
book all the way from new, by the now 86 yr-old one owner who's just
retired from driving.
PROBLEM:-
The engine CAN BE be perfect - starts well, idles perfectly,
accelerates
sweet as a nut and pulls very eagerly.
Then next trip out it starts and idles perfectly but has a bad
rough/flat spot - always (and only) just as you begin to put the
throttle down. Can be quite a bad kangarooing, or just a smallish rough
bit.
After you get through the flat spot with the throttle, it accelerates
right up beautifully and pulls like the clappers as normal. Same as you
go up thro the gears - each time you begin to pull away in the next
gear.
A bit worse from cold, and clears a bit as you warm up, but not
much....
Then a couple of days later you can drive all day on a long trip
without a
murmur of a problem; perfect again. The engine is also never randomly
rough - just
that bad flat spot as you begin to ask the throttle to open.
I've checked the many rubber pipes around the carb in case of
perishing, but they all look OK. I also worked over the electrics
even though I don't believe they're the culprit (changed leads and
plugs,
swapped in another coil as a test, and thoroughly polished up the
distrib cap - no sign of cracking or tracking). Also had the emission
checked - spot on legal. No exhaust leaks.
Any ideas would be much appreciated as I've reached a dead end.
Cheers.
Sorry this is so long, but I've spent a long time tying down the
problem & might as well give the detail to cut down the field a bit....
I have an almost perfect 1986 Astra L 1.6 petrol; OHV 16SV with 2E3
carb & Siemens MZV BY ignition module. 20 years old but only 29,000
miles genuine and almost 100% rust-free.
Brilliant - BUT I have one engine problem that's driving me nuts, and
I need fresh ideas please from anyone who can still remember cars with
carburettors!!
As background, the car has been immaculately looked after and serviced
according to the
book all the way from new, by the now 86 yr-old one owner who's just
retired from driving.
PROBLEM:-
The engine CAN BE be perfect - starts well, idles perfectly,
accelerates
sweet as a nut and pulls very eagerly.
Then next trip out it starts and idles perfectly but has a bad
rough/flat spot - always (and only) just as you begin to put the
throttle down. Can be quite a bad kangarooing, or just a smallish rough
bit.
After you get through the flat spot with the throttle, it accelerates
right up beautifully and pulls like the clappers as normal. Same as you
go up thro the gears - each time you begin to pull away in the next
gear.
A bit worse from cold, and clears a bit as you warm up, but not
much....
Then a couple of days later you can drive all day on a long trip
without a
murmur of a problem; perfect again. The engine is also never randomly
rough - just
that bad flat spot as you begin to ask the throttle to open.
I've checked the many rubber pipes around the carb in case of
perishing, but they all look OK. I also worked over the electrics
even though I don't believe they're the culprit (changed leads and
plugs,
swapped in another coil as a test, and thoroughly polished up the
distrib cap - no sign of cracking or tracking). Also had the emission
checked - spot on legal. No exhaust leaks.
Any ideas would be much appreciated as I've reached a dead end.
Cheers.