The fourth cylinder on my lanos 1.5L was misfiring. So I decided to be clever and I replaced all the spark plugs and leads. Big mistake. Now when I start it up it coughs and splutters for a few seconds then dies. I'm fairly sure I put the leads on in the right order. Please tell me if this is correct: Assuming that the cylinders are 1,2,3,4 when looking from the front of the car. I attached cylinder 1 to the top socket on the coil pack. Cylinder two to the fourth (bottom) socket. Cylinder 3 to the second socket down and cylinder 4 to the remaining third socket. I have tried a few other combinations but I'm faily sure this is right. So if it is right what now? How can I fix it? All help is apreciated, thankyou.
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Re: Not starting after replacing plugs and leads
This type of distributorless ignition system uses a “waste spark” method of spark distribution. Each cylinder is paired with the cylinder that is opposite it (1-4 or 2-3). Look closely next to towers on coil pack assembly they are numbered.
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Cold starting misfires can often be caused by either tired high tension spark plug leads or ignition coil packs. If replacing leads, then replace with a full, new set. Coils can be changed individually, but it is often the case that if one has failed, then the others aren't far behind. Some cars have individual coil packs on each spark plug. Some cars have a single pack for all plugs and some have coil packs which may control two or more plugs.
To check for a misfire (ignition failure) follow these steps:
(Cold start) (Use a pair of insulated pliers)
1) Start the vehicle
2) When the vehicle starts misfiring, disconnect plug leads or coil pack connections one at a time. If the vehicle idles even more roughly, then that plug or pack should be considered fine.
Replug each connection before disconnecting the next one. Once you disconnect a plug lead or coil pack connection and find no difference in poor engine running, then you have likely found the offending cylinder. Check the spark plug condition, lead and/or coil condition and connections on that cylinder.
have a compression test done to determine if valve or other chamber problem. change coil to another cylinder if individual coils to see if misfire moves . Change injector to another cylinder to see if misfire moves . IF it has HT leads then replace that lead with a new one and /or change that plug only too see if it is a plug problem. Check inside distributor cap for crack at that plug lead point.
having PO 304 = Misfire cylinder 4,PO 306 = Misfire cylinder 6, as I read above you have done the most. The thing that you have missed is to check whether the Catalytic Converter is faulty or not. To get an idea check whether you have a smell like rotten eggs at the end of the exhaust,you start having problems with cat and needs replacement. My advice before you go for a cat replacement is good to visit an MOT center and check your emissions and then you decide,
first code means random/multiple misfire cylinder (s) detected
second code means misfire detected number 1 cylinder, third code, miss=fire number 3 cylinder fourth code misfire number 4 cylinder
causes can be spark plugs, HT leads, ignition coils, injector, wiring fault, low compression/ engine mechanical fault
check fuel filter and check fuel for water or contaminents
then check fuel pressure with gauge also while driving
may have pin hole in leads - spray water with salt solution over HT leads while engine running and then rev to see or here spark jump(missfire)
recheck spark plugs - did you crack any on installation/removal/installation?
what are the codes and description if stored?
what is engine live data parameters like do they look normal (right specs for range/operation)?