Jump to content
SAU Community

Sick R34 - Pfc Problem?

Bill

By Bill,
in Engines & Forced Induction

 Share

Recommended Posts

Bill Collaborator

Bill

Posted
Posted

Lately my R34 GT-T has started knocking under medium load. (Moderate accelleration uphill)

It seems to be down on power and chewing through more fuel, I only got around 500k from the last tank.

I had a basic service last week, but if anything its gotten a little worse.

When it origionally started happening I thought it may be a bad batch of fuel, but that was several tanks ago now and its slowly getting worse.

I was wondering if its possible for a PFC to loose its tuning, and if so, how to tell?

Link to comment
https://www.sau.com.au/forums/topic/189995-sick-r34-pfc-problem/
Share on other sites
Bill Collaborator

Bill

Posted
  • Author
Posted
just take it back to the tuner and ask him to take a look. maybe timing needs to be changed marginally due to the heat.
It hasent really heated up out here yet, nothing like summer which was fine, and same knocking problems in the morning when its quite cool still.

I spose I will have to make a Trip to Sydney to visit a Tuner.

Also, geez bud, only 500 km??what do you normally get??
Normally 45L for 500k, this time it was 54L for 500k.

(most of my driving is commuting to work which is pretty much just hightway cruising.)

Bill Collaborator

Bill

Posted
  • Author
Posted
omg.... you get 500kms a tank on a highway is about right, you're complaining?

My main concern is "has started knocking under medium load."

As for the fuel economy, I would think noting that Its started using 9L more per 500km may be useful information to working out whats gone wrong dont you?

What mods you running?

FMIC, PFC, Eboost (usually leave it at 1/2 bar when commuting), Turbo back exhaust, Pod and thats about it. No changes here for a couple of years.

Power FC won't lose it's tuning. Even if it does due to the 'heat', it is very minimal.

Ok, so it wont drift, but any way it could have been reset if the battery was disconnected or something like that?

paulr33 Grand Master

paulr33

Posted
Posted

The ecu wont loose its tune or forget so its purely just how you are driving and possibly a bad batch of fuel

500 k;s to a tank is great so dont worry there. have a read of the powerfc faq (in my sig) it will cover most of your questions

JBird Contributor

JBird

Posted
Posted (edited)

Maybe you pressed a few buttons on the hand controller or somebody mucked around with it. This happened to a friend of mine.

If it is knocking, you can retard the timing using the hand controller - back it off a few degrees start at reducing it by 3 degrees until knock doesn't go above 20. This can be done in the mean time until you see your tuner...they should be able to sort it out for free if its a problem with PFC.

Also keep in mind, the RB knock sensor is pretty sensitive and may just be detecting other engine noise.

Edited by JBird
raps86 Rising Star

raps86

Posted
Posted

hey bill i live in bathurst and have never seen ur car i thought the only 34s out here were mine and the yellow gtr. anyway wat servo do u use? i have similar mods besides i have the profec b spec2 and hks bov. the weird thing is that im getin beter fuel economy now that its warming up im geting about 400 2 a tank of fuel city driving. But out on the road it doesnt change even when my mum drove my car to orange as i had 2 take her car 2 sydney 2 pick family up and she isnt a lead foot and only got 14l/p100k.

Anyway it mite have block injectors witch mite b not giving it enough fuel under medium load but the ecu could b trying to corect by opening the injectors longer when not under medium load and running rich. it mite b worthwhile gettin the cat check for blockage.

Bill Collaborator

Bill

Posted
  • Author
Posted
The ecu wont loose its tune or forget so its purely just how you are driving
Vey easy, think less than 1/3 throttle
and possibly a bad batch of fuel
I had considered this, but its getting worse after several tanks from a couple of different servos.
500 k;s to a tank is great so dont worry there.
its not so much the k's its the sudden change
have a read of the powerfc faq (in my sig) it will cover most of your questions
Thanks, will do so.
Bill Collaborator

Bill

Posted
  • Author
Posted
Maybe you pressed a few buttons on the hand controller or somebody mucked around with it. This happened to a friend of mine.
The hand controller is attached and just sitting in the glovebox, so I spose the buttons could have been pressed by other stuff sitting on it.
If it is knocking, you can retard the timing using the hand controller - back it off a few degrees start at reducing it by 3 degrees until knock doesn't go above 20. This can be done in the mean time until you see your tuner...
Thanks, will do so.
Bill Collaborator

Bill

Posted
  • Author
Posted (edited)
hey bill i live in bathurst and have never seen ur car i thought the only 34s out here were mine and the yellow gtr.
Its hard to miss Carls :O .

Mine is a more sedate Silver.

Ive had the R34 for well over 5 years now (first one in town :O )

anyway wat servo do u use?
Either of the Shells on the highway (depends which way Im driving at the time)
Anyway it mite have block injectors witch mite b not giving it enough fuel under medium load but the ecu could b trying to corect by opening the injectors longer when not under medium load and running rich. it mite b worthwhile gettin the cat check for blockage.
Now theres a thought....

I think I might change the fuel filter and take the injectors downtown and have them cleaned.

Edited by Bill
raps86 Rising Star

raps86

Posted
Posted (edited)

ok yeah mines a silver 1 2. i only use the 1 on stuart st as its got all new tanks in it. i just changed the fuel filter in mine and i got more out of that tank with the same driving style. when u change the filter have a clean container and drain the filter out from the in side and give it a blow and check 2 see how dirty the fuel was that comes out of it. mine was lookin like tea

Edited by raps86
  • 1 month later...
Bill Collaborator

Bill

Posted
  • Author
Posted

Cleaned injectors, changed filter and ran a few tanks through it since then.

Fuel economy is better, but not back to what it was (About 1/2 way there)

Still got the knocking under load :rofl:

spark plug type and fuel filter type the same after service

I think you may be onto sonthing here.

How long should iridium plugs last before being replaced?

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
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • Kaptain
      R33 general questions

      By Kaptain · Posted

      Im not entirely sure exactly what or where its leaking from, he started to pull the boots to swap to my new tie rods + ends and it just vomited fluid, so he closed em up up, swapped the rod ends to the old rods and let me know so I can figure a solution out, im guessing its all origional as as I passed 103k miles earlier this year im sure its just in need of a full overhual/rebuild anyways.    If i could just yank it off and be good it wouldn't be an issue to ship it out and wait for the turnaround but the guy I work with doesnt really have space to keep my car for a week or two at a time, would rather drop it off and have a replacement ready to drop in
    • GTSBoy
      R33 general questions

      By GTSBoy · Posted

      What do you mean by "seals"? Internal hydraulic seals (ie, is it leaking PS fluid?) or the rack boots that close the rack onto the tie-rods? Because the former is a rebuild, and the latter is trivial that you or any nearby mechanic could do. Dunno about the cowl. Just buy what you think is required and get anything else you find/break afterwards. Wing? Dunno. Don't like R33s enough to pay attention to them. Mirror glass is just glass (on the surface that you want to polish). Go for it.
    • Kaptain
      R33 general questions

      By Kaptain · Posted

      Hello! Long time lurker, been using the forums to address concerns and questions from afar for a while but I've struggled to find some answers so I guess its about time I made an account and formally asked some more knowledgeable people, since finding local skyline owners is hard (and shops that are knowledgeable or trustworthy to work on 'rare' cars are non existent out where im at, as skylines are quite uncommon to find in the wild around here). So the main 3 questions I have, 1: Steering rack has blown seals, well.. they kind of hold but they are not sealed properly anymore and as my R33 is my DD, i cant exactly rip the rack out and send it off or attempt to fix myself. As most refurb ones are around $1,100 or more shipped, and I have other things I need to work on around the car, I was seeking clarification on whether an S15 rack will more or less bolt right in, and whether a common mechanic could do any other required work to get it to fit. I ask, as I've found a supplier than can sell a manufactured as oem one for around 400, if not I'll likely order a used one from Jacks JDM, and take a risk on the seals there. The second question i have is that im replacing the front wiper cowl and have planned to buy 4 new clips and a new center clip but wasnt sure if there were any other clips that would also need to get replaced while I was at it. Given im sure any that are there now will simply break when I remove the old cowl... Last thing would be a fairly straight forward question, i think. If I manage (strong if, finding one has proven to be a pain) to find a R33 GTR spoiler/wing will it require much modification to bolt to a S2 R33 GTST? I've read the bolt patterns dont match but otherwise would bolt in, only options I have found with much luck is China stuff on ebay and carbonetics, which has a nice $650 shipping fee... so if anyone has any pointers where a US chap could locate one that would be great Random side question as well, the mirrors as I understand are mirror glass, and as im planning to polish my windows from water spots and surface scratches, i was hopeful cerium oxide would be fine for them too, as my research points to, but clarification is always nice. Any pointers would be appreciated, and while I have scoured the internet for answers if I missed a prior post somewhere that may answer these directly please point me towards it, as i must have simply missed it. I have seen a post here or there that has mentioned it, but I usually get 50-50 answers, or half answers... I dont have a lot of fab experience or mechanic experience, outside of hydraulic and pneumatic stuff I did in the military and with how hard it is to source stuff in the US, id rather not wing it and hemmoraghe money lol. Thanks guys! Sorry for the monumental first post haha
    • AdiR34
      Did tie rods. Steering now not "springing" back.

      By AdiR34 · Posted

      Yep, there's a very minor drift left that happens a few seconds after letting go of the steering wheel, but not enough to bother me. Enjoying the car still!
    • Keeper
      S A U N S W Club Membership

      By Keeper · Posted

      Got you mate. Check your email!
×
×
  • Create New...