Running On 5 Cylinders

[Wogan]

Hi everyone,

After taking my car out on the skid pan yesterday i noticed my car would occasionally lose power and sound like it was farting.. it's doing it all the time now and i'm pretty sure i'm only running on 4 or 5 cylinders.

My first guess of course is Coilpacks.. I've had a missfire under boost problem before (which turned out to be the CAS), but when i had the previous problem i araldited my coils because i heard it was a good way to fix leaking coils (as it's a good insulator).

My spark plugs are NGK iridiums gapped to 0.9mm and they've done under 15,000k's.

My oxygen sensor in the exhaust isn't reading overly lean or rich that i've noticed...

So my question is. How do i diagnose if it is the coils (or something else for that matter)?

[Sandeep]

while your engine is running, disconnect the plug to the coilpack. if the rpm drops or the car stalls then that means that the cylinder is firing, if there is no change in rpm then that means the cylinder is not firing. put the plug back on the coilpack and repeat the procedure for the other 5 coilpacks.

once you have figured out if one (or more) of your cylinders is not firing, swap the coilpack from a cylinder that wasn't firing with the coilpack from a cylinder that was firing properly. if the misfire moves to the other cylinder then you now know that the coilpack is faulty. if the misfire stays on the same cylinder regardless of which coilpack is swapped in, then you will need to start looking else where: spark plugs first because they are easy to check, then check wiring to the ignitor module for continuity, check if injectors are firing, compression test etc

[Wogan]

awesome thanks mate. Seems so logical now you've explained it... all i could think was "f**k f**k, stupid car"

[Rowdy]

hey mate,

i had a problem with my 6th cylinder not firing, and the coilpack disconnect and swap is the go. this will definaetly show up wether or not the cylinders are firing, but the coilpacks still might not be the problem.

you can put a long screw driver up to each injector, and put your ear to that, and you should be able to hear the injectors actuating, by way of a clicking sound. otherwise you can use a multimeter to see wether or not they are pulsing, by way of the voltage pulsing.

compression test is next.

i ended up trying an igniter pack and coil loom from another car, just to rule that out, but a check for continuity with a multimeter should be fine.

in the end my problem was the inlet manifold gaskets, and them being blown out. i checked this by spraying some startya bastard near the affected cylinders inlet tract, and the idle picked up and smoothed out for a second.

cost me 40 bucks i think for new gaskets, from nissan, and a couple of hours work.

hope this helps, Rowdy.

[Wogan]

ooo... that's interesting because i can hear a strange "hwoo" noise as it idles, so a blown gasket is definitely a possibility

[Rowdy]

ooo... that's interesting because i can hear a strange "hwoo" noise as it idles, so a blown gasket is definitely a possibility

ha ha id like to hear you make that noise in real life

another symptom of my cylinder not firing was the engine always 'hunting' at idle. when i fixed it, it smoothed out a lot. this made a funny noise...

let us know how you go

ciao, Rowdy.

[cabbie_bro]

I had an issue with my 5th cylinder. Replaced Spark Plugs and Coilpacks and it was still there, turned out to be my igniter module failing, i thought i was weird cause it was affecting just 1 cylinder, but it solved my problem.

[Wogan]

turns out i've got a valve sticking open in cylinder 1 .. looks like a recon for the head.. maybe a port and polish while i'm at it