Misfire Question - R33 S2 4,500-5,500rpm

[Levi_]

Ok, I know there's plenty of threads on this and I've spent a few days reading almost all of them, so here we go...

The Story

All started on the way back from a SAUWA country cruise the other week, after spending the whole day at highway+overtaking speeds (~3 hours of this) and we were heading home I went to overtake a car, so I dropped down to 3rd, foot down and started pulling out, then pop pop pop pop pop... Constant misfire over ~4,500/5,000, so I backed off, tried again and the same problem until around 6,000rpm where it goes back to normal.

While limping the next ~100KM home the problem grew a little worse, to the point I was getting intermittent misfiring at idle when at the lights. Additionally I was getting intermittent misfires on slow acceleration and steady driving speeds.

When I started the car the next morning the idle was fine but the misfire still happened every time I'd hit ~4,500rpm at wide open throttle (WOT). If I took it a little easier it'd make it through the problem range no problems.

Modifications

• Full turbo-back exhaust
  
• Manual boost controller turned up to ~11psi
  
• Front Mount Intercooler
  
• Apexi SAFC Neo II - tuned to 190rwkw
  
• POD Filter
  

Car gets good economy (around 9-12L/100km for highway stuff and 12-14L/100km daily driving) and has been rock solid since getting it 2 years ago.

What I've tried so far

• Regapped original spark plugs from ~1.0mm down to 0.8mm - No Noticeable Effect
  Plugs were pretty dirty but not dead.
  
  
• Taped up the sides of the coilpacks - No Noticeable Effect
  Few scorch marks (darkest on cylinder 1) on the side, tidied them up and used good electrical tape as all the guides suggested.
  
  
• Replaced spark plugs with brand new NGK Copper Spark Plugs pre-gapped at 0.8mm - No Noticeable Effect
  Figured I could save myself some money and get the cheaper copper plugs to diagnose the problem, will replace with better ones in 5,000-10,000km.
  
  
• Additional electrical tape applied to other parts of the coil packs to try seal them better - No Noticeable Effect
  Just following other suggestions from old threads/guides.
  
  
• Turned boost down from ~11psi to ~8psi - 80% gotten rid of misfire though obviously not an ideal solution
  
  

Checked for boost leaks, checked plugs/connections, AFM values seem to be correct - though it's hard to drive and monitor the SAFC screen at the same time.

The Big Question

What else can I try/check/test before spending $500-700 on new coilpacks?

I have a multimeter (if that helps) so I can probably test a few more things.

I'm still a little unsure if this could be caused by the cam/crank angle sensor or possibly an issue with my fuel pump / fuel pressure regulator.

Essentially I don't want to spend all the money only to find out that it's not my coilpacks. I've read way too many threads of people buying new coilpacks only to find the problem was still there.

[Cjmartz2k]

Do you have any spares? Are used ones hard to come by down there? If you can get your hands on a spare one or two (or three in a rail is best), you can narrow down which one it is pretty quickly and just replace the one. Factory coil packs with no misfire at 1.8 bar+ with the same coils for over a year here.

[Levi_]

Do you have any spares? Are used ones hard to come by down there? If you can get your hands on a spare one or two (or three in a rail is best), you can narrow down which one it is pretty quickly and just replace the one. Factory coil packs with no misfire at 1.8 bar+ with the same coils for over a year here.

Thanks for the reply, unfortunately I don't have a spare.

I've been looking around for just a single spare, but I know genuine Nissan items are very expensive here and I'd probably be paying ~$200AUD for a single coilpack and I'm not sure if running 1 spitfire in with 5 standard items is a good idea. Will ask around on the local WA forums though to see if anybody has a spare I can try.

Also, on another note, as long as I don't force my car into the misfire scenario (WOT, 500rpm @ 11psi) i still get good fuel economy. Dunno if that helps rule out fuel system issues.

[spec-V]

dude. save yourself time and money. its your coilpacks.

all the same mate.. check out JJR coilpacks, worked a treat in my R33

trust me dont waste your time dicking around with any shit, just save. buy coilpacks. put smile back on face. sleep happy.

i have owned 2 R33's both with same issue and helped friends with it on countless cars. its coilpacks. trust me.

[spec-V]

sorry forgot to mention check your harness, are they all in nice and tight? (have you done plugs recently and not plugged them in tight)

has a wire come loose in the harness? and whats your ignitor like?

again, ill bet your a 6pak its coilpacks

mine devoped the same way. i did the same shit you did, plus clean aac vavle etc etc. new packs and new PROPER plugs and we are win win win!

[Levi_]

sorry forgot to mention check your harness, are they all in nice and tight? (have you done plugs recently and not plugged them in tight)

has a wire come loose in the harness? and whats your ignitor like?

again, ill bet your a 6pak its coilpacks

mine devoped the same way. i did the same shit you did, plus clean aac vavle etc etc. new packs and new PROPER plugs and we are win win win!

Thanks for the reply, I think it is my coilpacks but I have more time to spare than I do money at the moment. I've still got plenty of car loan to pay off so I don't want to go ahead and spend a bunch of money before I need to.

My harness visually seems to be in pretty good condition, doesn't look to worn or anything and all the plugs are definitely tight and on right. I've had the plugs/coilpacks/harness out 4 times in the last week and a half, so I've had plenty of chance to solve a loose connection.

And the reliable nature of the problem leads me to believe the harness/plugs are fine, I can essentially makes the misfire come back/go away just by raising/lowering the boost. And it reliably happens at the exact same points in the rev range.

[jutstar]

deja vu :

1. Psychology. the illusion of having previously experienced something actually being encountered for the first time.

2. disagreeable familiarity or sameness: The new television season had a sense of déjà vu about it—the same old plots and characters with new names.

Answer, New Coilpacks.

[Lithium]

Thanks for the reply, I think it is my coilpacks but I have more time to spare than I do money at the moment.

Sounds very much like you are right, I don't know about this taping up trick - the way I did it was with silicone down the bottom/sides and that worked perfectly. My car really wouldn't tolerate much load before trying it and it has been going strong for a good part of a year since I did it, and am running >1bar on a GT30R with it.

How it looked after (foreground) and while (background) doing it:

The trick is the arc has found a weak path through the insulation on the side of the packs to the metal bracket they sit in and turn it into an easier path to earth than over the spark gap - so make sure its damn near impossible to use that path and fingers crossed it should sort it.

Since I have done it, other friends have tried it and also found it to work nicely Should cost you under $20, and takes bugger all time...

Edited September 14, 2009 by Lithium

[nicr4wks]

I replaced my coppers with more coppers and had no effect at all on the popping.

Replaced my coppers with iridiums and problem almost gone.

Up the boost to 11psi, problem comes back, not as bad as when the coppers were in. Coilpacks next.

[RANDY]

Like many R33 owners with this problem, my issue was the coilpacks. I replaced mine with other used (but good) packs that lasted for about 6 months then started doing the same thing.

I bought Splitfires ($550 or less if you look hard enough) and it's been 100% for the last year and a half. Either way, i'd replace them just for the superior spark splitfires put out.

I'd only stuff around with tape and glue if you *really* can't afford new coilpacks.

[Levi_]

Like many R33 owners with this problem, my issue was the coilpacks. I replaced mine with other used (but good) packs that lasted for about 6 months then started doing the same thing.

I bought Splitfires ($550 or less if you look hard enough) and it's been 100% for the last year and a half. Either way, i'd replace them just for the superior spark splitfires put out.

I'd only stuff around with tape and glue if you *really* can't afford new coilpacks.

Yeah, was only trying the tape trick to see if it was the packs causing the problem, will order a full set as soon as I figure out that they're the problem.

I'm going to borrow a single spare coilpack this week and swap them out one-by-one to see if it's just one failing.

[tm_r33]

as many above me have suggested, misfire due to coil pack problems is not at all uncommon in skyline motors. the coil-pack arrangement on rb20/25/26 series motors has always caused grief in stock and tuned motors. while many people on here will swear by standard coil-packs (even with heavily modded engines) just as many have had the same coil-pack related misfire problems. the problem being that heat and age cause failure of the insulation and a path through this insulation may be of less resistance than the spark gap at the bottom of the plug (air is an extreamly poor medium for volatge to pass through).

I DO NOT see the 'silicon fix' being ideal as silicon is actually a 'semi-conductor'. meaning under the right conditions silicon will conduct electricity.

while 'electrical tape' has an annoying habit of degrading quickly when exposed to excessive heat or gaseous environments (under bonnet provides both these non-ideal circumstances)

in summarry, quick fixes, not ideal.

[boostn0199]

just get splitfire coilpacks I had exact same symtoms and dont be cheap and get another brand get splitfire and you wont have a problem and if you do get missfire with splitfires just re gap sparkplugs

[Lithium]

I DO NOT see the 'silicon fix' being ideal as silicon is actually a 'semi-conductor'. meaning under the right conditions silicon will conduct electricity.

in summarry, quick fixes, not ideal.

Silicon is a semi-conductor, which would be why I never mentioned using it. Silicone is an insulator, hence the fact you can buy silicone designed specifically made for insulation of electrical componentry.....

As I said before, I am almost a year and counting with not even a flinch from my >150,000km old coils which were previously misfiring - I have a post from where I found this solution which I will update if I ever start getting ignition breakdown again.

Edited September 15, 2009 by Lithium

[benl1981]

Having an issue with mine also. Problem somwhat better after placing some silicon on coils. Still have 1 left to insert with the coating.

Sometime the car will revout without misfiring (running about 18psi boost- probelm if you run any more than about 11 or 12 psi). Is the any way to check the ignitor module or coil harness. I guess the coil harness I could check the continuity along each of the sections and the ignitor module from the specs in the manual.

I just don't know if the silicon trick is working. I have the red gasket maker that i've coated them with and it seems to hold well.

Annoying problem. I have 10- coil packs so I've been swapping them out - coating them putting them back in.

Don't want to spend $500+ on splitefires, only to find out it's the module or the harness!

Edited September 18, 2009 by benl1981

[Jdfnq]

Having an issue with mine also. Problem somwhat better after placing some silicon on coils. Still have 1 left to insert with the coating.

Sometime the car will revout without misfiring (running about 18psi boost- probelm if you run any more than about 11 or 12 psi). Is the any way to check the ignitor module or coil harness. I guess the coil harness I could check the continuity along each of the sections and the ignitor module from the specs in the manual.

I just don't know if the silicon trick is working. I have the red gasket maker that i've coated them with and it seems to hold well.

Annoying problem. I have 10- coil packs so I've been swapping them out - coating them putting them back in.

Don't want to spend $500+ on splitefires, only to find out it's the module or the harness!

Coil packs just don't last forever and ever and ever etc etc etc....

No matter how much you want to tape them/silcone/glue/make love to/etc, eventually THEY ARE GOING TO DIE!!!!!!!!!!!!!!!

Just replace them......

if you can't afford splitfires, (and they are shitloads cheaper thah OEM crap) then jump on ebay or google and buy an inferior (usually) cheaper alternative

[Gloss33]

So i was having this same problem and after consulting the forum replaced my coil packs with Split Fire coil packs spent the $500 got them sent up and guess what 2 months later I'm having the same problem again. Surely "Split Fire" coil packs are meant to last a lot longer than 2 months now it looks like i am going to have to spend the money again just to be able to "drive" my car like i used to be able to.

is it possible the problem is coming from anything else i changed the plugs in the hope that was my issue but its still the same ....

[paulr33]

it would seem unreasonable that new splitfires would last 2 months

ive had splitfires in mine for about 2 years ish now and no problems

i would expect 10 years from a set of coils? given the stock ones die around 15years ish ?

id say something else is causing an issue with your setup

it could be a few things, so check everything and check the basics

usually the often most simplistic and basic thing can make it run like ass

ie check bolts, plugs, cables, connectors, joiners, wires, hoses etc

[SiR_RB]

i had the same problem in my r33 gtst series 2, tried gapping the plugs down to 0.7mm (from 0.8mm) and it was still miss firing up high. even did the silicon job and it didnt go away...

i kept researching on here and found out that r34 gtr's have the same coilpacks as r33 series 2's (in built ignitor)

i was lucky enough to find a set of r34 gtr v-spec 2 coil packs on here for half the price of new splitfires done over 10,000kms with them @ 12psi and no problems what so ever

[Newy]

superspark.com.au... Jamie is a top bloke. Great price, mine are brilliant. i run 1.1mm gap at 11psi not a problem in the world also cheap $3 NGK spark plugs are as good as any from my experience!