way to test for multiple cyilinder misfire.. is this safe... ???!!!

[SRiz]

this is a quote from someone who was banned so maybe i shouldnt even listen to it but this is what he said... " pull the spark plug wire up and see if it sparks nicely to the valve cover when the car is running. if you pull each one individual and notice that when one of them you pull has no effect on engine speed at idle thats the one that is misfireing for sure. " im having mulitple cylinder misfire and cant figure out if its from the coil pack or compression.. or maybe just cause its been humid and the spark is traveling away from where its suppose to go... ne ways is this statement true , i just wanted to maybe have a way of eliminating one thing off my list of possible reasons... is there any kind of test I can do to see whats causeing this? I already changed plugs and wires and it helped but it came back eventually!

 

[IHeartTurbo]

You can, but it's not very good for the ignition. All that flyback voltage can (not saying will) travel all the way back and possibly fry the ecu. I've done that method myself many times, but it's really not a good idea.

 

[BISHILVR]

worse than that it's not safe!!!, the coil packs on the 4g63 generate enough voltage and current to send your heart out of rythem!!!, it's been known to happen and people have actually died from it, this is not your lawn mower ignition, and the thing is that the misfire that the ecu is detecting is probably not even noticeable to the human eye, the ecu can detect a misfire in milliseconds, say maybe the engine only misfires once every 5000 revolutions and under a certain load, actually most 1st gens misfire way more than that but it's never known because the first gen ecu is not that picky. so really, what i'm saying is that a scanner from a dealer that will log misfire counts for each cylinder and display them, is the best method. the other thing is that it depends on how badly it is missing, if it's a real bad miss and you can notice it while idleing or driving BEFORE the light comes on, then you might be able to find it at home, but if your going to check plugs for sparking just make sure that you remove the plug wire and lay it on the manifold with a spark plug in it BEFORE you start the engine, and then shut off the engine and repeat for each cylinder. Like i said though for that method to work, you have to have a pretty bad miss.

 

[SRiz]

hmm... ok well i dont wanna die sooo... its not that bad of a misfire i can feel it coming on but its a multiple cylinder misfire so the code wont tell me what cylinder... maybe ill get a full engine diag to see where its coming from is there a way to check the coil pack I hear they are the main reasons for MULTIPLE cylinder misfire?

 

[BISHILVR]

the easiest way to test a coil pack is to swap it for a know good one, but if you can't do that you can use an ohm meter and the shop manual to check the coils resistance on the primary and secondary windings. the thing is though coils can go bad in other ways that can't be detected with a ohm meter, the method is more for detecting a complete failure.