Mysterious Pfc Missfire In An R32 Gtr

[GTRsean]

From my experience and Scotsman who spoke to racepace a while ago. He said ben said some pfc's do it and some don't. It seems to happen when the pfc jumps out of or into closed loop - using the o2 sensor. You can stop it by turning the o2 sensors off I have been told.

Didn't read the whole thread though. Am I close??

Mine were always off. Still did it. Tried the old extra ground to the ignitor trick, no good......

Carton to the person that gets rid of this damn hiccup for good!

Edited July 10, 2008 by GTRsean

[Cubes]

I had mine tuned slightly leaner last time around so the o2 sensor was disabled. Still did it. Almost always when cruising and coming off the throttle only slightly and then back on 'slightly'.

[Rowdyr32]

I have been told the igniter earth lead does nothing and is not needed.

Mine does it when cruzing and I must just move the pedal a little. Does get annoying at times.

Oh well good luck guys!!!

[donkey]

hey my r33 gtr with fc does the exact samething, about 80-100kmph, every 15 min, will have a miss, hesitation

[donkey]

hey my r33 gtr with fc does the exact samething, about 80-100kmph, every 15 min light throttle will have a miss/hesitation

[ax53b70p25]

i have the same problem but i have splitfire coils, hks ignition amplifier new plugs and earth lead and still does it, i am however going to put a new ignition sub harness hope this fixes it.

[ow_damnit]

a little more information if it helps anyone with ideas, i run PFC 8.04a and suffer from the hesitation. a little while back i swapped it out with a mate running the exact same version, ran it for a period of maybe 3 - 4 weeks without a hitch. swapped back and the problem came back with it. so it was looking like it was only specific units, however recently his has started getting the problem after a long period of hassel free driving... as mine was second hand when i first received it and his only played up after a while, could it be somethin that comes with age? something breaking down?? has anyone had the problem with a new from the box PFC?

[paulr33]

i'd be interested in the pin connector (blue thing) and the state of it

is your securely fastened and neat or is the wiring shabby and kinked etc?

it could be something as simple as the pins for the ign for each cylinder is a little weak/finicky

and when users remove the stock ecu and fit the PFC its enough movement to make it not contact properly

its a long shot , but would explain how your mate now has the issue you mentioned - only after removing ECU and plugged in a new one

so it could be the connector on the car side (blue plug) or the socket on the BNR32 PFC's

[femno]

Yeah i got this prob too, does it once every couple of weeks...sucks to do it every 15 mins! farrrk

put in splitfires STILL DID IT

changed the ignitor STILL DID IT

changed the cas STILL DID IT

added earth wires STILL DID IT

I got over it...seems too hard.

Any other model car do it? Like 33 GTSt etc..

[paulr33]

does it do it when the hand controller is unplugged

[ow_damnit]

yes does it without hand controller, i try leave my controller unplugged so stupid passengers dont go "ohhh can i play the playstation" and pick it up and end up with god knows what. as for my wiring, you could say its a bit of a mess its an accomplishment in itself to unplug the thing.

Ive just removed my twin turbos and replaced with large single so its going for a tune next week, ill ask matt spri at PITS if he has any ideas that man knows PFC's like the back of his hand.

Edited July 23, 2008 by ow_damnit

[cefiro]

Tried regrounding the ignitor pack and no sucess, has anyone tried to contact apexi in japan and ask for a fix. Maybe it maybe a companent in the ecu which is not soldered in, software????? This is very annoying

Anyone tried running datalogit with sucess maybe a solution if someone does.

Edited July 28, 2008 by cefiro

[paulR32gtr]

Mine is doing this too - such a pain. I think Paul you might be on to something with the pins - going to get in and push on each of the IGN wires hope it makes a different.

Some days it wont do it at all, other days it will do it every 15 minutes.

[leeanmel]

add another one to the list...

i have recently purchased a 96 gtr33 with an existing pfc ver. 5.01a

i am having the same missfire problem.

hope we can find a fix!!!!!

[kismetcapitan]

I had never had this problem with my BNR32. I have a completely new ignition system, all looms, earthing kit, HKS DLI twin power, Splitfires. But I had my engine rebuilt, and since getting it back, I get this damned hiccup/stumble at around 2500rpm at light throttle. It usually misfires once, but sometimes twice.

I question whether its an ignition problem because I have wideband logs. If it were an ignition misfire, the AFR would spike rich, and ignition cuts are smooth anyways. This hiccup is a slight jolt, and if you've ever hit a fuel cut limiter, you'll know just how bad a fuel-cut jolt can be!! Anyways, when it misfires, the AFR spikes LEAN. Meaning, the ECU is cutting an injector or two...implying a software bug.

But the thing is, it hadn't done it before. Only after getting rebuilt, and my earthing wires did get moved around to different locations. I'll try to put them back where I had them, see if that makes any difference.

[Swiper the Fox]

"Its the plugs"

Stacey Diemar 2004-2008

[nsta]

Add me to the list!!!......

i have a 95 r33 gtr, with power fc, and have the occasional hiccup with the car at light loads, generally ~2500-3500rpm....

Im so used to it now it doesnt bother me (so long as it doesnt damage its all good)......i have it happen once every few days....

[Beer Baron]

both my 32 GTRs have done it. one didn't do it for years, maybe 2 or 3 years with the PFC fitted. then out of the blue it started. not very often though, and it's not very bad, just a minor anoyance. the other GTR had big $ engine, turbos, cams, AFMS, the full monty and it did it too. the PFC in the first one I bought used (but 8.04a) the other one I bought brand new also 8.04a.

I must confess I've done bugger all to fix it. but the first car I mentioned is about to get new AFMs, new injectors and brand new engine, and new coil pack harness and new grounding kit so hopefully it disapears.

[SLYDA]

Have u replaced the O2 Sensor?

[Adriano]

I had never had this problem with my BNR32. I have a completely new ignition system, all looms, earthing kit, HKS DLI twin power, Splitfires. But I had my engine rebuilt, and since getting it back, I get this damned hiccup/stumble at around 2500rpm at light throttle. It usually misfires once, but sometimes twice.

I question whether its an ignition problem because I have wideband logs. If it were an ignition misfire, the AFR would spike rich, and ignition cuts are smooth anyways. This hiccup is a slight jolt, and if you've ever hit a fuel cut limiter, you'll know just how bad a fuel-cut jolt can be!! Anyways, when it misfires, the AFR spikes LEAN. Meaning, the ECU is cutting an injector or two...implying a software bug.

But the thing is, it hadn't done it before. Only after getting rebuilt, and my earthing wires did get moved around to different locations. I'll try to put them back where I had them, see if that makes any difference.

Sounds like ignition problem. When tehre is a missfire, the AFR goes lean, as an O2 sensor measure oxygen, which there is plenty when there is no spark.