Mysterious Pfc Missfire In An R32 Gtr

[nobby]

this would seem logical and explain the intermitteancy of the misfiring

maybe its only when the power is turned up and the accuracyt of the spark is critical

ie with stock ecu and stock power its fine

turn the wick up and change ECU and its critical

Yep, this was my reason for looking inside the loom in the first place.

I noticed that every time the factory earths were touched or added to things got better, but soon after returned to bad idle and missfire returned and not always with the same frequency, sometimes every 15 min, then redo earths and once a day.

My guess is that the apexi pfc is sensitive to the poor earth.

You can add all the earths in the world, but if the power can't get to your new earths.

Can someone please look at their loom and have a go at fix to confirm my fix.

The crimps near computer did look nice and clean, but once I soldered them I did notice an improvment.

and the crimps in coil loom however looked like the were the real cause of the problem, not coroaded but tarnished.

Hope this fixes your car to, but I'm still leaning towards the problem rearing its head again as the is still alot of these crimps throughout the looms, take a good look at wiring digrams available in the manuals cheap on ebay.

GOOD LUCK

Edited August 14, 2009 by nobby

[nobby]

Well it's been nearly a week and 300klm since I soldered the looms and even though I said problem would proberly return.

IT HASN'T. car running better than ever.

car does have a multi earth in engine bay conected directly to battery.

I mention this because I only noticed a difference when I ran one to ignitor, but the miss returned.

[IOWNU]

Wow good news.

I have the same problem, annoying, isn't constant but it does occur randomly from time to time, while cruising only under very soft acceleration.

[nobby]

Wow good news.

I have the same problem, annoying, isn't constant but it does occur randomly from time to time, while cruising only under very soft acceleration.

Sure is, I recon there is a number of faulty connections burried within the oem looms and this said a number of different problems are accuring, hence the problem that eludes so many.

I hope I'm right that this is all the problems is, but a pain in the ass to find and repair all faults.

[KR4-GTR]

Well it's been nearly a week and 300klm since I soldered the looms and even though I said problem would proberly return.

IT HASN'T. car running better than ever.

car does have a multi earth in engine bay conected directly to battery.

I mention this because I only noticed a difference when I ran one to ignitor, but the miss returned.

hi mate,

well done on fixing the fault!

would you happen to have pics or diagrams of the fix!?

please let me know.

cheers!

[Stock GTR]

From my experience both the 32 and 33 PFC's suffer from this problem, but it was corrected in the 34 PFC model.

I don't think its a problem with the oem wiring, just the PFC's of earlier days. Mainly happens under cruise loads! Don't know if there is a solution available.

[nobby]

hi mate,

well done on fixing the fault!

would you happen to have pics or diagrams of the fix!?

please let me know.

cheers!

Sorry the pics I took arn't clear enough to send.

If you know how to solder and have the proper tools and time to do the job correctly have a go.

I tryied not to use any acid to clean, just fluxed solder but did have to use acid on a couple, but

I did use electronic cleaner spray on all joints after solders and sealed them back up with self amalgamating elec tape around soldered joint and normal elec tape to rebuild loom.

tape avail at jaycar it's expensive around $20 a 10m roll, it does stretch though, and worth it I recon.

cheers

Edited August 20, 2009 by nobby

[nobby]

From my experience both the 32 and 33 PFC's suffer from this problem, but it was corrected in the 34 PFC model.

I don't think its a problem with the oem wiring, just the PFC's of earlier days. Mainly happens under cruise loads! Don't know if there is a solution available.

So why do you think the wiring isn'nt the problem?

The tarnish that was on my wiring and how much off an improvement fixing these connections made was enough for me to think , hay heres something and hopefully pass on a fix for others to benifit.

My pfc I purched new 2 1/2 yrs ago. and have watch my car slowly get worse over the last year or so.

I'm not saying I fixed it and this is the soloution only that it seems to of solved my problem instantaly.

I'd also like to add, an improvement in fuel economy, 2 lt better per 100k .

My engine is running smoother and even my father inlaw who's no car nut told me he can hear how much better it sounds.

Not trying to fly my flag I'm just very happy how it's turned out for me.

cheers

Edited August 20, 2009 by nobby

[paulr33]

BNR32 PFC and BCNR33 PFC are the same unit, which is why they would likely have the same issue

[Beer Baron]

the problem is 100% the fact that the power FC is more sensitive to weak earthing that the factory ecu. you add more earth, clean up wiring etc problem gets better. so yeah the fault as such is not the wiring, but improving it removes the fault (power FC earth sensitivity). that's been my experience with this problem.

[paulr33]

i agree

so how does one fix - is it fixable inside the ecu somehow

[nobby]

i agree

so how does one fix - is it fixable inside the ecu somehow

If ya can remember back a while the problem was only with 32, and now its 32 and 33.

So with that said, is it possible 34 will soon have aged wiring also and the problem happens to it also.

Lets hope not, with luck nissan decided to improve joints in loom.

I'd been talking with my mechanic about this miss and he said he'd given up trying to find the cause. as he'd lost count how many hrs spent looking also.

To tell the truth my mechanic told me about the joints near computer, and that why I soldered them, but i then noticed in wire diagrams that there was more of these crimps in the loom so I looked for the easyest ones to also fix and lucky for me I found the ones that were realy causing a problem.I don't know if all joints near computer are all earths so don't assume they are and earth them, i just soldered them to improve connection

DON'T RUN EXTRA EARTH DIRECTLY FROM COMPUTER AS SOME OF THESE ARE ACCUATLY NEG SWITCHING CIRCUITS AND BANG THERE GOES YOUR COMPUTER UP IN SMOKE.

now remember I never said this will fix problem, but touch wood sofar my fault has gone 2weeks and 500 +k's.

good luck

[horn]

Hi,just to read about other peoples dramas with the PFC is an eye opener.

I had my PFC fitted about 4 years ago,had an earth kit fitted beforehand with earth wire to igniter. It had the miss from day one at 80km/2600rpm but only rarely.I complained to tuner,he said cant find/see anything.Learned to live with it but over the last 6 months its gotten worse to the stage i nearly got wiped out merging on to the m4 when it started spluttering/popping etc.

I dug out the stock ecu and popped it in today and what do you know it runs lovely,haven't driven it to work yet (32km)but it felt better, idled better even with the cams. when i got the car it had an earth fault to the fuel pump,i soldered a load of earths near the ecu but eventually traced it to a faulty alarm relay. I had even moved the igniter to no avail.

Has anyone found any more earths to solder.

my pfc is .PFC GTR33L 020-1188

Cant see what the h/c reads as the ecu is out of the car.

cheers

Edited October 13, 2009 by horn

[horn]

I drove it to work this morning and only noticed one very little hiccup but on the way home i was able to hold the revs at 2800rpm and it would run very slightly rough but no where as bad as with the pfc.I think I'll have to check the TPS and maybe the earths again.

Edited October 14, 2009 by horn

[nobby]

I drove it to work this morning and only noticed one very little hiccup but on the way home i was able to hold the revs at 2800rpm and it would run very slightly rough but no where as bad as with the pfc.I think I'll have to check the TPS and maybe the earths again.

a problem at certain revs!, could be AFM's, Igniter, CAS , tps do a pretty basic job- unlikely but you never know.

Do you have a Manual to check these, if not get 1 asap as its a wealth of info on checking this sort of problem yourself, and you can spend the rest on something more important like new injectors etc

[Pal]

hey guys, sorry to open a old thread but having this problem at the moment. done a service (plugs and oil) on my r33 gtst with PFC and now having this intermittent miss. thinking i had a bung plug i changed all the plugs but it is still there. ok under power but has little misses at about 80km/hr under light load. did other guys sort out there missing problems or is it still common. im about to rip out the coil packs and get them tested but i dont think its them as the car run ok before the service and is fine under load at high rpm. im going to have a look at the earthing of the igniter module as well. any other ideas. cars got following mods

pfc

high flow turbo

550cc injectors

[nobby]

hey guys, sorry to open a old thread but having this problem at the moment. done a service (plugs and oil) on my r33 gtst with PFC and now having this intermittent miss. thinking i had a bung plug i changed all the plugs but it is still there. ok under power but has little misses at about 80km/hr under light load. did other guys sort out there missing problems or is it still common. im about to rip out the coil packs and get them tested but i dont think its them as the car run ok before the service and is fine under load at high rpm. im going to have a look at the earthing of the igniter module as well. any other ideas. cars got following mods

pfc

high flow turbo

550cc injectors

If it were the coils, they should play up even more so the higher the rev's and power would fall also.

So if this seems OK then doubt it's the coils.

Mind you it never hurts to check all you can, but doubt it's the cause of the miss.

When it comes to electrical faults, some are a pain at times to trace the cause.

[GTRAAH]

Mannn still no fix? Mine does it like once a week or few days a quick hiccup then drives perfect. Do you think i should changed the earch? Man this HAS to be fixeddd MUSTTTTTTT .. im going to talk to my tuner at Hills see if he knows anything.

[GTRAAH]

Has anyone officially fixed it?

[nobby]

Has anyone officially fixed it?

No sorry to report soldering joints has not been the only solution.

But soldering done and when the miss returns I unplug (with ign off) conectors around coils, ignitor etc a few times and this seems to fix things for a while.

so electrical resistance at the joints would appear to be the problem.

also to note that I have not fiddled with extra earths the last couple of time, so these don't appear involved in miss.

now to work out, which conection is the culprit.

this is not going to beat me.

Edited February 1, 2011 by nobby