random misfire!! .please help.

kinglarry001

i've had my eml on for couple of months (since i found out there was no bulb in there)

got a vauxhall speacalist to plug in the diagnostic thingy, and it came up with random misfire. nothing to say what was causing it.
so i bought a brand new coil pack (as the mechanic suggested) but dont think it has made a diffence. it had new spark plugs in couple months ago. and new battery.

she isnt properly missfiring. the eml is on constantly, and now and again flashes.

any ideas?

MikeS

join the club

i am thinking it is overfueling due to the coolant temp sensor

kinglarry001

i've got no idea mate! i aint mechanically minded lol

but its starting to do my head in!!

it flashes when im accelerating hard, so i drive like a granny, yet still flahes. no ryme or reason for it to flash!!!

MikeS

means the misfire is fucking up the cat

kinglarry001

but my car doesnt seem to actually misfire though! i dont think! what should it feel like iif it is?

MikeS

mine is intermittant

starts up fine then it starts to idle rough, then it doesnt like revving then after revving the car starts to misfire at idle then when revving it misfires

if i take my foot off the gas then most times it tends ease off

also fuel consumption is shite

misfire sounds like an impreza turbo

feels like a tank

kinglarry001

but wouldnt it come up with a fault code though? thats what i find strange

mine doesnt sound as bad as yours

MikeS

my code only came up twice in the last week

flashing for about 10 secs m8

maybe cos i know wot to look for i am more sensitive about it

also the problems are intermittant not all the time

i think the cylinders are flooding due to overfueling

gonna replace cts 2morrow

kinglarry001

cts?

MikeS

coolant temp sensor

only costs 10 quid or sommit

does your car struggle to reach operating temp

like over 80c ?

MikeS

http://www.yourfilelink.com/get.php?fid=481410

this is my car 50% of the time when running

use realplayer to get video as well as sound

kinglarry001

no video mate.

been speaking to peeps on vvoc. and some one said about egr vavle, just dissconected it and went for a drive, eml didnt flash.

if i was to leave it unplugged while driving, will that cause problems/damage?

vocky

you need to fit a blanking plate to eliminate the egr valve.

running with it disconnected will give an eml, but won't affect the engines running, a duff egr valve will cause poor idle.

misfires can be caused by;
coilpack - you have tried that
spark plugs - use triple electrode plugs
crank sensor - not a common problem
fuel filter - worth doing anyway
injector - try some injector cleaner (then replace the fuel filter)
jumped tooth on the timing chain - has the timing chain been replaced ?

kinglarry001

so would a duff egr valve cause it to misfire? the eml light is constantly on anyway, i've gotten used to it lol

vocky

the egr won't cause a misfire, just poor running / tickover, they usually stick open, so if you unbolt the two bolts you can remove the valve and see if it's duff. If the plunger isn't fully shut then it's duff (the plunger lifts up away from the solenoid)

kinglarry001

if it was f*&ked, then would it cause my eml (the one with pic of engine on) to come on and say random misfire on the diagnostic computer the mechanic conected?

MikeS

it if was fucked then the eml light would come on and show the code

simply unplugging it will create another code but wont solve the problem

p0300 means variable cylinder misfire

how can it be the coil as it is variable, same goes for injectors

it is caused by over fueling or under fueling imo

the coolant temp sensor controls fueling and ignition, also the egr valve

kinglarry001

i dont know what the code was. just that the dispaly read random misfire

MikeS

p0300 is random misfire

same as me doh !

kinglarry001

ah, just that looking through the fault code list, it had cylinder /something (getting tired now lol) random.