Jump to content
SAU Community

Recommended Posts

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 by itbmils
  • Replies 212
  • Created
  • Last Reply

Top Posters In This Topic

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.

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

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

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

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 ?

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 by markjh27

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.

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

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

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 by R31Nismoid
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

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.

Are you guys running O2 sensors On or Off

Have you tried the alternate, to whatever setting you have

mine does it too :thumbsup: - 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 by Driver

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • As discussed in the previous post, the bushes in the 110 needed replacing. I took this opportunity to replace the castor bushes, the front lower control arm, lower the car and get the alignment dialled in with new tyres. I took it down to Alignment Motorsports on the GC to get this work done and also get more out of the Shockworks as I felt like I wasn't getting the full use out of them.  To cut a very long story short, it ended up being the case the passenger side castor arm wouldn't accept the brand new bush as the sleeve had worn badly enough to the point you could push the new bush in by hand and completely through. Trying a pair of TRD bushes didn't fix the issue either (I had originally gone with Hardrace bushes). We needed to urgently source another castor arm, and thankfully this was sourced and the guys at the shop worked on my car until 7pm on a Saturday to get everything done. The car rides a lot nicer now with the suspension dialled in properly. Lowered the car a little as well to suit the lower profile front tyres, and just bring the car down generally. Eternally thankful for the guys down at the shop to get the car sorted, we both pulled big favours from our contacts to get it done on the Saturday.  Also plugged in the new Stedi foglights into the S15, and even from a quick test in the garage I'm keen to see how they look out on the road. I had some concerns about the length of the LED body and whether it'd fit in the foglight housing but it's fine.  I've got a small window coming up next month where I'll likely get a little paint work done on the 110 to remove the rear wing, add a boot wing and roof wing, get the side skirt fixed up and colour match the little panel on the tail lights so that I can install some badges that I've kept in storage. I'm also tempted to put in a new pair of headlights on the 110.  Until then, here's some more pictures from Easter this year. 
    • I would put a fuel pressure gauge between the filter and the fuel rail, see if it's maintaining good fuel pressure at idle going up to the point when it stalls. Do you see any strange behavior in commanded fuel leading up to the point when it stalls? You might have to start going through the service manual and doing a long list of sensor tests if it's not the fuel system for whatever reason.
    • Hi,  Just joined the forum so I could share my "fix" of this problem. Might be of use to someone. Had the same hunting at idle issue on my V36 with VQ35HR engine after swapping the engine because the original one got overheated.  While changing the engine I made the mistake of cleaning the throttle bodies and tried all the tricks i could find to do a throttle relearn with no luck. Gave in and took it to a shop and they couldn't sort it. Then took it to my local Nissan dealership and they couldn't get it to idle properly. They said I'd need to replace the throttle bodies and the ecu probably costing more than the car is worth. So I had the idea of replacing the carbon I cleaned out with a thin layer of super glue and it's back to normal idle now. Bit rough but saved the car from the wreckers 🤣
    • After my last update, I went ahead with cleaning and restoring the entire fuel system. This included removing the tank and cleaning it with the Beyond Balistics solution, power washing it multiple times, drying it thoroughly, rinsing with IPA, drying again with heat gun and compressed air. Also, cleaning out the lines, fuel rail, and replacing the fuel pump with an OEM-style one. During the cleaning process, I replaced several hoses - including the breather hose on the fuel tank, which turned out to be the cause of the earlier fuel leak. This is what the old fuel filter looked like: Fuel tank before cleaning: Dirty Fuel Tank.mp4   Fuel tank after cleaning (some staining remains): Clean Fuel Tank.mp4 Both the OEM 270cc and new DeatschWerks 550cc injectors were cleaned professionally by a shop. Before reassembling everything, I tested the fuel flow by running the pump output into a container at the fuel filter location - flow looked good. I then fitted the new fuel filter and reassembled the rest of the system. Fuel Flow Test.mp4 Test 1 - 550cc injectors Ran the new fuel pump with its supplied diagonal strainer (different from OEM’s flat strainer) and my 550cc injectors using the same resized-injector map I had successfully used before. At first, it idled roughly and stalled when I applied throttle. Checked the spark plugs and found that they were fouled with carbon (likely from the earlier overly rich running when the injectors were clogged). After cleaning the plugs, the car started fine. However, it would only idle for 30–60 seconds before stalling, and while driving it would feel like a “fuel cut” after a few seconds - though it wouldn’t fully stall. Test 2 – Strainer swap Suspecting the diagonal strainer might not be reaching the tank bottom, I swapped it for the original flat strainer and filled the tank with ~45L of fuel. The issue persisted exactly the same. Test 3 – OEM injectors To eliminate tuning variables, I reinstalled the OEM 270cc injectors and reverted to the original map. Cleaned the spark plugs again just in-case. The stalling and “fuel cut” still remained.   At this stage, I suspect an intermittent power or connection fault at the fuel pump hanger, caused during the cleaning process. This has led me to look into getting Frenchy’s fuel hanger and replacing the unit entirely. TL;DR: Cleaned and restored the fuel system (tank, lines, rail, pump). Tested 550cc injectors with the same resized-injector map as before, but the car stalls at idle and experiences what feels like “fuel cut” after a few seconds of driving. Swapped back to OEM injectors with original map to rule out tuning, but the issue persists. Now suspecting an intermittent power or connection fault at the fuel pump hanger, possibly cause by the cleaning process.  
×
×
  • Create New...