Mysterious Pfc Missfire In An R32 Gtr

[itbmils]

OK peeps

I posted a thread here a while back (6 months or more ago) asking for input on an intermittent miss fire I am getting on my PFC equipped R32 GTR.

At that stage I had ....

new iridium spark plugs

replaced AFMs

new plug leads (yes GTRs do have leads)

new ignitor

new split fire coil packs

I was looking for some input on where else to look – but I got feedback from a few guys that this sort of thing was 'common' with PFCs (common may be over stating things - but I was not the only one seeing this problem)

Can anyone confirm that this is a 'know issue' with PFCs ?

Anyone found a way to fix it – can the PFC be software (firmware) upgraded smehow ?

The reason I ask is that my miss fire seems to be getting worse. If seems to happen more often now, and also when under load. So a small miss fire when cruising along at 80 klms is no big deal, but a miss fire at full noise is something that I would like to fix.

PFCs seem VERY common - and I had no hesitation in getting one when I did my engine rebuild about 18 months ago - but no one mentioned at that stage that they have these sorts of problems.

It's not a big deal - but I would like to get to the bottom of it

============= UPDATED ====================================

OK this is a list of the userids that have reported this 'missfire' problem on this and my other thread. If you see your ID in this list can you pls let me know what model (GTR?) you have and the PFC software version so we can do some analysis. If you want me to add you to the list - let me know.

Userid...............Model..........PFC Version

===========================

itbmils...............R32GTR.......8.04a

markjh27.............................8.0

Amaru

SLIPPERY

GTR-80Y

GTR1993..........R32GTR.........8.04a

Driver

Tonnyk

NIB

JSWR32.............R32GTR.......8.04a

GILLIES2001 R32 GTR

Edited August 7, 2006 by itbmils

[Amaru]

Havent driven my car since October last year but it was still doing the same thing then (cruising along, it would just briefly miss). We watched the PFC tracer and looked at the cells it was running across when it happened and nothing seemed out of the ordinary, and we couldnt come up with an explanation for it.

However, a couple of GTR's that have had PFC's fitted since have also started doing the same thing (and they have been tuned by a few different places).

I think its just a bug you live with. If its getting worse it may indicate a different problem starting to rear its head.

[SLIPPERY]

just thought id add my experience. ive previously used a power FC in a GTR and it did the same 'miss' when cruising at light loads, say, every couple of days. sort of felt like the CAS was cutting out. wasnt like a slight 'pop' miss either, more like a hard jolt

[itbmils]

just thought id add my experience. ive previously used a power FC in a GTR and it did the same 'miss' when cruising at light loads, say, every couple of days. sort of felt like the CAS was cutting out. wasnt like a slight 'pop' miss either, more like a hard jolt

yep - that's it - so you can imagine how that feels when you are actually hard on the peddle

[paulr33]

ive never heard of this as a common problem, but what do i know

anyway it would be useful if you give some datalogit logs as this would give ample information to debug it. again assuming a sensor is actually seeing what the problem is, it could be simple leak/coils/breakdown problems.

what are the consistent things you see/know of when the problem occurs?

day?

night?

cold?

hot?

have you tried temp IGN adjust? less timing

have you tried temp INJ adjust? more fuel

whats the highest knock you see when it happens?

do you put the same consistent fuel in it each time ?

[markjh27]

YES, i have this same friggen problem, i have a r33 gtst with a rb26 in it.i had my power fc installed a month ago, and i will be doig like 100k's and out of nowhere it will jolt only for a second. It doesn't happen all the time and u can't pin point whats going wrong ort when it;s gonna happen! I would also like to know if anybody knows how to fix this! As i don't want to be at full noise and have it go boom!

I find it happens day or night, doesn't seem to matter what weather conditions are, however it only happens when the car is warm. Not that i flogh my car when it's cold but it doesn't happen streight away, only when the car has been driving for a little while. Also doesan't seem to matter what speed, only when it's conmsisten or somtimes taking off.

Edited June 13, 2006 by markjh27

[Amaru]

For me it only ever happens when cruising on light throttle. Its not a tuning problem as it sits around the same part of the map, and we have been through it and its all ok (if it was bad mapping, it would constantly complain sitting around those cells).

I have been told by a number of reputable tuners across Australia its simply a "bug". Have seen it happen in many R32 GTR's tuned at many different places, with completely different running gear.

[paulr33]

given the popularity of the r32 rb26 and PFC i would still doubt a bug. what version do you get reported by ETC, VERSION.

and others who "see" this problem, what version PFC

[markjh27]

Hey bud, mine is version 8.0

[GTR1993]

Man, mine does EXACTLY the same thing, maby once a day u get a miss, mostly light load but this is because most of the driving is light load. Ill get the numbers off my FC if you want?

[paulr33]

well if its a bug, its likely to be a pattern. perhaps version checkign may help

[itbmils]

ive never heard of this as a common problem, but what do i know

well neither had I until I got a half dozen responces and PMs that last time I posted this question

I then assumed it was 'common' and something I needed to live with

anyway it would be useful if you give some datalogit logs as this would give ample information to debug it. again assuming a sensor is actually seeing what the problem is, it could be simple leak/coils/breakdown problems.

Agree - but I do not have datalogit !!!

what are the consistent things you see/know of when the problem occurs?

day?

night?

cold?

hot?

any time - mainly when hot - but can happen when cold

have you tried temp IGN adjust? less timing

yep - no diff

have you tried temp INJ adjust? more fuel

yep - no diff

whats the highest knock you see when it happens?

my know readings sit at about 30-50 - but I have a noisy engine

Do you put the same consistent fuel in it each time ?

yep - BP Ultimate every time - different servos - and I've tried octain booster

Edited June 14, 2006 by R31Nismoid

[itbmils]

well if its a bug, its likely to be a pattern. perhaps version checkign may help

well - I'm running Version 8.04a

[paulr33]

can u post a link to the original thread ?

[itbmils]

can u post a link to the original thread ?

yep

http://www.skylinesaustralia.com/forums/in...topic=89658&hl=

[itbmils]

Well this sucks, u pay 1450 for a comp and it has a damn misfire, that is not on. i am gonna try and get throguh to apexi japan and see whatr i can do. i will let u all know how i go.

Cheers Mark

go you good thing

The point of this thread was to try and judge how 'common' this problem actually is

[markjh27]

Yeah fair point i have deleted the thread.

[GTR-80Y]

same prob.....32GTR happens maybe once a week. Very quick miss and just feels like a jolt. Knock readings show nothing out of the ordinary.

I have had it once on full load knock and other readings seemed fine tho.

Really seems like a random miss with nothing to do with load or temps or driving conditions.

[R31Nismoid]

Are you guys running O2 sensors On or Off

Have you tried the alternate, to whatever setting you have

[Driver]

Are you guys running O2 sensors On or Off

Have you tried the alternate, to whatever setting you have

mine does it too - maybe once a day or less?

tryed using a spare set of afm's.. just incase but it still happens

just happens randomly - usualy just while cruising along at any speed

Edited June 14, 2006 by Driver