Misfires, etc. What to do first?

[Dice]

Hey fellas

I've currently got a 95 R33 GTS-T with a full 3 inch exaust sheilded pod filter and a bleed valve currently set back to standard boost.

I started to get a misfire a while ago when I really gave it a foot full. Soon after, two coils died. It's been mission impossible trying to get replacements, they keep sending me the wrong parts. Anyway I eventually tracked down a couple to replace them, then it started misfiring again. Tried turning the boost back down to standard and it's been fairly good like that. Still gets the occasional misfire, but nothing major.

But the question remains, why should it be misfiring. I've looked around here in old threads regarding coils, can't seem to find anyone in exactly the same situation. Some people have told me it could be the fuel pump too. It's been running ok on stock boost for about a month and a half now. If the coils were on their way out, shouldn't they have died completely by now?

One option I was discussing with the fella who's doing the work on my car was, chucking in a wolf 3d, and re-doing the ignition with different coils etc. It's a pretty pricy option. Looking at about $2500 all up.

But since the car needs a few things, (namely a respray) I'm getting an extension on my loan to do all the work. If I go for the new ECU and ignition, and a respray. I can afford either a clutch upgrade OR a front mount. The stock clutch has slipped real bad on me a couple of times. Only on the odd occasion though. I'm guessing it'll probably get worse with the ECU upgrade and more boost etc. Would it be more beneficial to upgrade the clutch first or the intercooler?

Once again, sorry if these questions have been asked before. I don't get much time to browse through these forums often. I just needed to get some ideas on which way to throw my hard earned cash.

[Steve]

Have you checked your plugs - thats the first place I would be looking.

As for clutch of ecu, if your clutch is slipping, well all the power mods in the world wont make your car go any better, just burn the clutch further until its undriveable - easy choice.

[predator]

it wasn't the coils then obviously.. I notice a lot of people going "oh must be dodgy coils" - i think the actual number of cases where it *is* the coils is a little overstated. Coils shouldn't go wrong and they are build reasonably well. But I am sure they can go wrong, like anything.

i mean there are all sorts of things that can make your car seem to "miss" and some can be mistaken for a miss when its something else. like does it do it on gear changes, when you take your foot on (hard) or simply off the accelerator, during coasting along, lumpy at idle, etc. all can indicate where the problem could actually lie.

like steve says.. first thing on any car to check condition and general health of the car is the spark plugs themselves. Will tell you more than any other method i can think of, of what the problem could be.

[riceline]

how do you check the coil pack's to see what health they are in?

[meggala]

yep set your plug gaps to .8 mm then look for other issues if this doent work the coils oin r33's are good for 500hp so dont listen to the mechanic If you really want after market ecu go power fc but no need to go there till you change turbo's at least. and wolf isnt that great any way plus you car wont pass an epa inspection with the wolf attached. look for the threads re after market ecu's the subject has been covered heaps.

Might be time to look for a more skyline experianced mechanic they are n't alway the cheapest but they can save you big dollars down the track.

lastly when it come to cars there is one golden rule borrow money for the car but dont borrow money for the mods. why cause mods are dead money and you will not see most of it back.

If you want some idea's re which wayto go for mods read this

http://www.meggala.com/modys.htm

cheers

meggala

[Dice]

The plugs were all replaced when I got the first 2 coil packs replaced. The first two coils were definetly screwed as the spark was arcing out onto the head. The misfire happens then you really put the boot into it and get up around 6000rpm. I've been told by one fella that the spark might not be stron enough and is getting blown out or something like that. It does it realy bad on 10psi, but only occasionally on 8psi.

The respray pretty much needs to be done asap. The clear coat on the roof is peeling off. And it gets worse every time it rains.

Can anyone reccomend anyone in Brisbane or the Sunshine Coast QLD who really knows Skylines?

[Guest Robo's]

Your mechanic is correct, the extra boost is blowing out the spark. It happened on mine on a recent dyno tune, except it was blowing them out at 13psi and running fine at 10psi. We closed the gap down to 0.7 and it cured the problem. Also richness in fuel causes miss fires too.

[neil_se]

I've got a missfire at the moment (at least that's what i think it is) consistently between 3500 and 4000rpm. I've cleaned the AFM and coil packs, checked the resistance of the coil packs, put new spark plugs in, but still prevails. Hopefully its just because i'm running rich (i constantly get backfires on gear changes and releasing throttle) and it can be sorted out on the dyno. The only thing i've noticed about the coil packs is that 5 are rb20 coils with the metal spring on the end and 1 is a later model coil pack with the black filament, could that be the cause?

[Duncan]

for both ppl above who put in new plugs, were those plugs gapped to .8 or .7? No point putting in new plugs if you have a 1.1 gap on them, it will not fix the problem.

[Roy]

Check the gaps, my experience with coils has been that when they start to play up, then they play up all thru the rev range, not just at a certain rpm when being kicked in the gutz. Id be looking at plug condition or the plug gap... as other have said

...If you really want after market ecu go power fc but no need to go there till you change turbo's at least. and wolf isnt that great any way plus you car wont pass an epa inspection with the wolf attached.

Whats makes you say that???

I know AFM are a more effecient way to tune a car for emissions, but CSVs use Motec (ie MAP)and comply with all pollution regs. The range of Bullet Roadsters, including a supercharged V8 uses the Wolf ECU and again it complies with all Aus pollution regs.... and if it is a Map thing then many Toyotas use MAP sensing.

Every Power Fc car ive either been in or followed around the track are tuned to run that rich for safety that they arent going to pass any sort of inspection either. I doubt many std, or reasonably standard 8-12 year old cars will pass, the average catalytic converter is only good for about 50,000kms before they give up the ghost, and if you have dumped an exhaust, filter perhaps a sprinkle of boost on your car, then the changed A/F mixtures are likely to cook the catalytic converter even quicker.

I may be reading too much into the statement, but it sounds as though a Power Fc equipped car would pass an EPA inspection... (if they really know what they are looking at as far as modified computer, and no AFM in front of a turbo, then leave it in place, if you are really concerned about flow, then sell the functioning one and buy a stuffed one and rip the probe out the internals.)

blah, blah, blah, chr1st i can dribble sh1t :Oops:

[Dice]

Well, this morning I pulled all the plugs and regapped them at .8. Cranked the boost back up. Took it for a spin and no more misfire. But later on this evening when the air started to get cold, the misfire came back. Not as bad, but still pissing me off. Should I pull the plugs again and gap them at .7?

I'm seriously thinking of investing in a SAFC.

[neil_se]

Mine are already at 0.8 as well.

[calemb]

What sort of plugs are you using?

[knore]

Is it possible to gap iridiums to 0.8

It says on the box not to gap them because of the 'fine iridium point'

Has anyone gapped them before? They are currently on 1.1mm

[crooser]

Well, this morning I pulled all the plugs and regapped them at .8. Cranked the boost back up. Took it for a spin and no more misfire. But later on this evening when the air started to get cold, the misfire came back. Not as bad, but still pissing me off. Should I pull the plugs again and gap them at .7?  

I'm seriously thinking of investing in a SAFC.

sounds like you are another victim of the ecu overfueling/timing retarding scandal, i had the same problem until i swapped my old link ecu back in on saturday.

anything above stock boost was always a problem.

smooth as power to redline now - forgot how much fun it was

[Dice]

sounds like you are another victim of the ecu overfueling/timing retarding scandal, i had the same problem until i swapped my old link ecu back in on saturday.  

anything above stock boost was always a problem.

smooth as power to redline now - forgot how much fun it was

So the go would be to get an aftermarket ecu? Would I need to go for a whole new computer or would an SAFC do the trick?

[croat]

Dice i have exactly the same problem as you do. It will run good for a day or so but on a cold night the missfire with start when the boost is up. Its like a popping out of your exhaust right? I will change my plugs and get a power fc when i get a chance and have a look at my coils. Does anyone know how or where to go to get your coils checked out? Last i remember when i took mine out my mechanic said that they are a bit burnt???

[Steve]

I know AFM are a more effecient way to tune a car for emissions, but CSVs use Motec (ie MAP)and comply with all pollution regs. The range of Bullet Roadsters, including a supercharged V8 uses the Wolf ECU and again it complies with all Aus pollution regs.... and if it is a Map thing then many Toyotas use MAP sensing.

Roy, can you point me in the direction of any evidence that street built cars are being complied to aust standards with Aftermarket ECUs? I am doing a bit of research into vehicle emissions, aftermarket ECUs and compliance with ADRs.

Cheers heaps for any help.

[meggala]

my point roy is that its cost time and money to get an aftermarket ecu adr approved and street legal in victoria at least 3k for the test not to mention the dyno time and the risk to the engine when runnign it such a lean condition but back to the wollf Iwas unaware that they had a plug in model and take that back. ment to mention it in the thread but I got side tracked and forgot steve just remided me.

one of the major things is the ecu has to locked and sealed for the car to get adr approval in victoria at least.

meggala

[Steve]

can you lock power fc?