Cylinder 3 Just Isnt Firing :(

[siddr20]

Hey everyone

I have a bit of a problem, and i dont know how its happened

One night (friday nite), when i went to go start my car, it just struggled.

Sounded like it was running on 5 cylinders and after few checks its exactly what it was doing.

I took each plug out while the car was running and cylinder 3 just wasnt doing anything. eg) while the car was on, i removed cylinder 1 coil pack plug out; it will drop a cylinder, however number 3 just didnt do anything (remained the same)

I changed the coil pack from say cylinder 2 to 3, and still cylinder 3 does nothing.

I put the coil pack against the block and started the car to see if there was any spark, but didnt notice anything..

I really dont think theres anything wrong with my coil packs, but perhaps the wiring loom itself..

So i got the multi meter out, but after doing a few tests, it just seems like theres no voltage going to coil pack 3.

Theres nothing wrong with the spark plugs (cylinder 3 plug is a little black-but i guess due to the fuel being dumped into it while the car is turned on)..

Took stock ecu out and plugged in my power fc and still cylinder 3 doesnt fire.

Its just cylinder 3.. All other cylinders seem fine.

Has anyone else experienced this before? Any help/advice is much appriceated.

Only thing i can really do is to borrow someones wiring loom and connect it up to see whether it works. If anyone in sydney is willing to help me out please do let me know

Cheers

ps- if you need any more info let me know.

thanks

edit: mods for my car are: full exhaust, pod filter, r34 cooler, stock ecu/turbo.. nothing else!! I dont really see how this will affect it, but just giving as much background info as possible. Also spark plugs are coppers re-gapped to 0.8 (been using it for 1.5 years now- changed every 5000kms)

Edited December 3, 2007 by siddr20

[BHDave]

If there's no spark and the problem stays with cylinder 3 despite swapping coils about then i think you are right that it's a wiring problem. (assuming you have no igniter based on your car being an s2)

The last thing to check before delving into wiring is the spark plug. Swap it with another one to be sure

As far as the wiring goes, all coils have a common power, a common earth and an individual trigger.

So you have determined you have no power to the coil, i assume by searching for 12V? just as a check before stripping back the loom, check for continuity from the power plug to all of the coil plugs. If 3 shows nothing then you just need to strip that section back and find the break in the wire.

[siddr20]

i really aint confident stripping those wires back and checking if theres is a broken state somewhere.

See the thing is, it just happened out of know where.. Not like i was mucking around with anything etc..

[Adriano]

Does the engine have an igniter at the back of the coil cover? Either that or it could be a dead injector, but youll need to chech for spark again.

[UCD15R33]

series 2 check ur ecu had a similar problem where I go double spark to a coil every time and blew a coil pack 2 minutes later

[Mr_G]

I was helping Sidd with this last night. It appears its only one of the wires on #3 going to the igniter, not the ground or the other one, but the pink one which is the trigger wire that is coloured different for all 6 coils. That was the one that wasnt reading the voltage. Guess the best bet is to swap the look going to the igniters and see how we go? If its not that, then its got to be the other half of the loom going to the ECU id presume...

Alternatively as a ghetto fix, could I just tap into the wire off another igniter from say #4 ?

Dave, it is the individual trigger that doesnt read the voltage.

Edited December 2, 2007 by Mr_G

[Adriano]

Definately cant hook it up to another pin on the igniter. If you have a scope, hook that up to the wire in question, it should be a switched earth, ie the igniter pulls the voltage to ground. Have you tried swapping the igniter for another one?

[MBS206]

You won't get to read a voltage on that wire unless you have a CRO

It is a VERY short burst to trigger the coil to ignite (I beleive it grounds it actually.)

You would need to look at the wave form on a CRO to see if anything is happening.

Have you done a compression check?

Don't just immediately blame electricals. So far the check you have done is inconclusive.

[fr0st]

I had my #3 cylinder drop out when my CAS started clogging up with dust from a blown bearing in the cas itself. Was a pain in the ass to find the problem.

Could be worth taking the CAS off and making sure it spins freely (should spin very very easily with no noise at all) or if you can open yours blast some contact cleaner through it.

You can also check if your ignitor is working with a parker globe, just touch the legs on the + and - of the coil pack connection and see if it lights up at all. It should just be a dim flicker. Either that or buy a cheap multimeter that can measure frequency and check it that way.

[siddr20]

Have you done a compression check?

No i havnt.. Perhaps tomorrow night after work i can do it.

But im sure the compression will be healty across all cylinders.

If theres no voltage or spark coming across the wiring loom to that cylinder then logic just says, theres something wrong with that wiring to plug 3. Since all other cylinders are getting voltage etc.

Well mbs206- i really dont know what else to do in terms of testing by myself.. Dont really have much tools etc etc..

I think i might just borrow someones wiring loom - atleast im narrowing it down if it works or not..

frost- so howd you find that out tho? might give that a go too then.. worth hurt if i cant find the problem

Edited December 2, 2007 by siddr20

[wrxhoon]

If you are 100% sure you don't have spark on number 3 then check all electricals . Try this very easy test : Take number 3 spark plug out and connect the coilpack back on it, take a multygrip or anything else that is well insulated ( otherwise you will get a belt) and while you are grounding the spak plug on the cyl head, someone can crank the engine , then you will know for sure if you don't have spark.

[siddr20]

didnt understand what you meant sorry.

So take spark plug out and connect the coil pack back on it?

So what am i doing with the multigrips? holding the spark plug against the coil pack and seing if theres a spark??

im totally lost as to what you meant sorry..

Well i have put the coil pack against the block and cranked the car, but i couldnt see any spark coming out of it..

Also i have swapped coil packs from cylinder 3 to 2 and it works.. So nothing wrong with my packs..

[SECURITY]

swap your CAS with a known working one.

[wrxhoon]

Spark plug out , fit the coil pack on to it as if it was in place, ( you don't need to hold the plug on the coil pack it will hold by itsef) this way if all works the plug should fire across but it must be grounded as you need + and - . The reason you need insulated muti-grips to hold the assemby ( plug with coilpack), if all works you will get a belt. How else would you hole the plug on the body of the cyl head , if you use your hand you will get a belt!!

[Simon-S14]

dont even have to take a plug out, find any old 2nd hand plug and hook it up to the coil pack. make sure the electrode is earthed on the motor somewhere and then crank it over, if it doesnt spark you have an issue, if it does spark then i would say the injector is an issue. best way to test this is with an LED test light, The injector plug (probe it while cranking) should have pulse on one of the wires. If its pulsing then you can eliminate it to a dud injector. If no pulse then your injector wiring needs attention.

if you have no coil pack spark, and you have tried swapping the packs... then i would say its a broken wire in the coil pack loom somewhere

[siddr20]

Ah yup understood.. Cool well i will give this a go then

Just gotta find time, coz im working every day this week then going overseas next sat.. otherwise might just do it when i come back!!

[MBS206]

No i havnt.. Perhaps tomorrow night after work i can do it.

But im sure the compression will be healty across all cylinders.

If theres no voltage or spark coming across the wiring loom to that cylinder then logic just says, theres something wrong with that wiring to plug 3. Since all other cylinders are getting voltage etc.

The only multi meter I can think of off the top of my head is the Fluke 87 to detect if you have spark, as it has a min/max range.

The time that the pulse is for, is VERY minimal, and the gap between pulses is MUCH MUCH larger then the gap of the pulse.

Hence, a multimeter (Average one) will just read 0V whilst that wire is pulsing away.

Try hooking a led light with resistor in series with it across the + and - terminals and see if it is dimly lit (Use aronud a 600 Ohm resistor in series with the led light.)

Also make sure you hook the led light up in the correct orientation to avoid blowing the led light.

But you MIGHT be able to see a dimly lit led light this way. (This is also a slightly inconclusive test as you may not see it, but it's still pulsing)

The only true way is to use a CRO.

Also do a resistance check from one end of the loom to the opposite end of the wire. If the reading is < 0.7Ohm, the loom is fine.

[siddr20]

Hmm interesting..

Would anyone have this and willing to help me out?

[blind_elk]

The advantage of using the plug in #3 is that you may be able to observe any damage to the electrodes, such as might be caused by a chunk of piston playing pin-ball inside the cylinder and combustion chamber (been there, done that!)

[siddr20]

Sorry you totally lost me there

So what exactly did you fix and how and why etc .. lol