R33 Gtr Missing

[tricstar]

car started to miss, mainly above 5000 rpm in first and second. So I put in some new spark plugs same as last ones NPK coppers 0.8mm from memory. It has split fire coil packs which are less than a year old....Still missing quite badly especially above 5000rpm in first....

from trawling heaps of threads on here I've read, people talking about "crank angle sensors " ....and it beening the cause of their car missing..............does my problem sound like it could have anything to do with the crank angle sensor......

a little bit of extra info on mods done ::

dejetro pfc---so no afm's

can't think of anything else that could be related, any help or words of wisdom would be appreciated

[BIT SUS]

car started to miss, mainly above 5000 rpm in first and second. So I put in some new spark plugs same as last ones NPK coppers 0.8mm from memory. It has split fire coil packs which are less than a year old....Still missing quite badly especially above 5000rpm in first....

from trawling heaps of threads on here I've read, people talking about "crank angle sensors " ....and it beening the cause of their car missing..............does my problem sound like it could have anything to do with the crank angle sensor......

a little bit of extra info on mods done ::

dejetro pfc---so no afm's

can't think of anything else that could be related, any help or words of wisdom would be appreciated

I know this sounds simplistic, but check for boost leaks.

[tricstar]

I know this sounds simplistic, but check for boost leaks.

thanks

how do I check apart from looking and listening, & wouldn't a leak just reduce the boost I see on my boost gauge or evc -- still sees 18psi as before ??

[Sheriff Wan]

Unsure on 26's if they have an exteral ignitor or not - check that.

Also what boost are you running and what was the gap on the old plugs?

Post the part number of the new plugs too - could be the wrong heat range/type as its NGK not NPK......

[mad082]

pretty sure the rb26's have an external ignitor pack, which could well be the problem since you have ruled out the other 2 possibilities.

[tricstar]

yeah Sheriff they are NGK .8mm same as before, typo in first post... 18psi

yes rb26's have external ignitor, and have quizzed the guys at my local workshop who say if it was that it would more than likely miss right through the rev range and under load , eg 3rd & 4th on the gas ..it doesn't only 1st & 2nd above 5000rpm when reving up fast.. they think probibly crank angle sensor............I have it booked in tomorrow so hopefully they will get to the bottom of this and I will post up the result

cheers guys

stand by

[tricstar]

this is getting really annoying, its been missing as above for nearly two months except this morning when I went to the workshop it didn't miss a beat, they checked the odvious stuff again eg spark plug , coils etc took for a hard drive and it never missed once so they though what else can we check this is fine,,

then I pick car up and 30 minutes later its missing again, as above ????

I'm not convinced its a spark problem anymore, ( I'm starting to question everything ), now I'm worried it could be fuel which could be dangerous ......

what to look for, any easy thing to check.............fuel pump maybe

what do I do, short of just start replacing stufff like injectors, fuel pump , regulator etc and there is still the crank angle sensor??

nothing worse than an intermitent problem

got an event in a couple of weeks, need to get this sorted...............................

[mad082]

if it was a fuel problem you could tell by the colour of the spark plugs. also it wouldn't really be a missfire (unless it was an injector not firing properly). if it was the fuel pump then it should get worse under high load in the higher gears as that is when the fuel pump will be working the hardest.

does the problem happen when the car is cold, or only after it has been driving around for a while? if only when hot i would start by getting a new ignitor (although since you have already replaced coils and plugs it wouldn't hurt to get a new ignitor as well).

[tricstar]

thanks mad

took the mechanic for a spin this morning and it missed ( hooray ) he said definately a miss not fuel..

So back in on monday to go through ignition system ( especially ignitor & crank angle sensor ) he's already checked gaps, plugs, coils..........

[R.3.2.G.T.R]

replaced fuel filter recently?

[tricstar]

ok well this isn't going help anyone...........

got car back from shop today , all they did was put new plugs in gapped to 0.065mm took for drive , car didn't miss so problem fixed...

the other plugs where new gapped to .08mm ( couple were closer to .085mm ) as before..heat range 6..

Questions ,,, does anyone else with RB26 running 18psi have to run such a small gap, thoughts on plug gaps,,,,,,,,,,,?????

[Harry50601]

just a quick thoughts on gapping the spark plug to solve misfiring problems, im mean like down to 0.6mm n under. would it cause "heat spot" on the piston?

[mad082]

i would doubt it as it isn't really any different to having a bigger gap (as far as heat goes)

[kaiden]

yep

[ShadowGTR]

18 psi is a reasonable amount of air being forced into a small space, having a larger gap, or even a normal one can end up with the boost air blowing the spark out. lower the gap means you have a more intense spark, less likely to be blown out. iridium and platinum plugs are also sensitive to higher boost levels which is why most revert back to copper.