mysterious misfire

[nova_172]

i have a misfire on my nova 1.2spi, i hav tried almost everything and know its not the dizzie, plugs, leads, i seems to be a misfire on cylinders 2 and 3. any ideas

[mowgli]

coil, plugs, or a bad connection. book it into a fastfit diagnostic place. it will save you money in the long run

[M_U_T_A_N_T21]

do a cylinder preasure test to see how much preasure is in each cylinder they should all be the same if there is a preasure drop in one of the cylinders then id sugest taking the head off probly a valve or somin

or make sure there isnt an air leak spray some wd40 on the inlet manifold if the engine revs pick up slitly while doing this you may have an air leak where your spraying it

[nova_172]

basically all i did was take the throttle valve off and clean it, wen i put it bk on it started strait away but the next mornin it wouldnt start it wud jus fire every now and then, i did a pressure test about a month ago and they were all 160, all i noticed yester day was fuel drippin form the carb by the manifold gasket, but it looked like it was coming out of the spring taht closes the throttle val;ve.

[M_U_T_A_N_T21]

did you clean it out with carb cleaner

[nova_172]

my mate did it wiv brake cleaner and compressed air

[M_U_T_A_N_T21]

id rebuild the carb if theres leaks on it clean all the jets and and new gaskets

[M_U_T_A_N_T21]

if there is a misfire check to see if all 4 plugs are sparking take 1 plug out at a time and plug it into the lead an hold the plug close to an earth on the engine when you turn it over it should spark if they all spark then its not the coil,leads,dizzy and plugs

[Aragorn]

does it misfire when running?

if so try this:

start it up and ensure idling happyish

get some carb cleaner and spray loads of it along the inlet manifold to head mating face top and bottom- the idea being if theres a leak thats drawing in air it will draw in carb cleaner and the revs will rise or fall

have a good look round the bay and listen for hissing, mine had an air leak on the brake servo pipe and was drawing in air - idled like a bag of shite but drove normally - u could here the air hissing in very clearly - make sure the little vacuum hoses that goto the airbox and throttle body are attached and theres no split hoses

failing that try to see where he fuel is leaking from, if fuels getting out airs getting in and take a pic of it if u can