not sure if running on all cylinders

ive recently got an 1982 1.6 running after being stood for 10 years. New fuel pump, new oil, fuel and filters engine sounds kind of ok but when i disconnect one of the spark plug leads it doesnt do anything where as the others drop the revs right of and nearly stall it. Ive swapped spark plugs and leads its not them, ive cleaned in the dizzy cap. im wondering if its compression problems not sure any help please!!

if you pull the plug lead off the suspect cylinder while the engine is running and move it five or 10 mm up the plug but not fully off you should hear an audable ticking, tyhis is the sound of high tension electricity jumping the gap from lead end to spark plug, this shows all is ok with the ign / ht leads if not then that needs further investigating, if you can hear the ticking then you may have a compresson problem, sticking rings or valve problems, to check properly you need a compression tester to confirm cylinder pressures, try the first option 1st and keep posted, i asume you have changed the spark plugs, hope this helps

Or the injector is stuck closed

yes i can hear the electricity noises when i take the plug on and of, i have not put new spark plugs in yet but have swapped them around with the good cylinder doesnt change the problem with the suspect cylinder.cheers

sound like you know what you are doing, sounds like a compresion problem now,could be a sticking compression ring, this may sound a bit drastic but its worth a try, spray a load of wd 40 or something like it into the bore, dont be shy with it, leave it in to do its business at least over night, next remove all remaining spark plugs and turn over the engine using the starter, cover the plug hole with a rag to catch any wd coming out, refit your plugs and start her up, if this works you might get a bit of smoke out the back till it burns it off and of course you will need to change your oil, if it doesnt then it may need the head off for more investigation. dw

Cheers mate I'll give it a go, let you know

I'm with Lhasa

I'd do an Injector test (linky on the left) then if that's all ok, look into the compression

I seem to have had a bit of luck, seems it was the injectors decided to swap one off a good cylinder into the dodgy cylinder. Fired it up and all four were firing nicely seems like I disturbed a bit of shit the seals seemed good too. Gonna buy some system flush hope that cleans it up a bit, Ive got hold of a compression tester I'll check it anyways, cheers for the help.

I will do the injector test aswell as soon as I've got the rig set up