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

    • The Bogan
      MLR's Bogan cruise ship

      By The Bogan · Posted

      I ❤️ Matty I would like to thank Matty for going out his way in securing me a OEM NC detachable hard top for the NC Matty, your worth your weight in gold, and I cannot say how much I really appreciate your outstanding help I'll get it colour matched once I pick it up sometime in Dec-Jan 😁  
    • Rezz
      OEM Soko: Japanese business supplying Automotive items from Japan - Freebie inside!

      By Rezz · Posted

      We have some genuine Japanese legally decommissioned car number plates now in stock 🙂 Add some legitimately obtained JDM style to your Skyline or other Japanese model, or simply as a garage/man cave decoration! About the 40mm hole: The Ministry of Land, Infrastructure & Transport in Japan recognised the popularity of keeping decommissioned plates among car enthusiasts and came up with a method to "destroy" (or render them unusable for street use) while still retaining their collectable/usable value for display etc.  We have 40mm hole covers available to cover the hole nicely with a Sakura motif, which are also available in white in (very!) limited quantities, however they frequently sell out. Please let me know if you're wanting one or more of these and I'll check availability. The Sakura motif covers are more common. https://www.oemsoko.co.jp/products/genuine-decommissioned-japanese-vehicle-number-plate-set-su-7515 https://www.oemsoko.co.jp/products/genuine-decommissioned-japanese-vehicle-number-plate-set https://www.oemsoko.co.jp/products/genuine-japanese-vehicle-number-plate-400mm-hole-cover *Please note that we can't obtain particular number or area name (eg: "Gunma 500 Fu ・86") if requested. All plates are provided as they become available after decommissioning. 
    • MidnightR32
      RB20DET lean on cold start

      By MidnightR32 · Posted

      Ah, fair enough. For the IAT, I'm using a legit GM sensor that was used on the car prior to my current build. I'll get another wideband and IAT ordered and follow up when they show up. Thanks for the help.
    • GTSBoy
      RB20DET lean on cold start

      By GTSBoy · Posted

      You shouldn't need to massively fatten up the mixtures for cold conditions. For one thing - 0°C is not that cold. For another, the Haltech will be using the IAT sensor to tell it how dense the air air, and calculate the correct amount of fuelling. Then the cold start enrichment is added as a % on top of that, so it should scale with the main fuelling. You might also doubt the IAT sensor at this time. You're not using one from an RB26 are you? Using a nice Bosch sensor or similar? Happens. Some wideband units take great pleasure in killing their sensors. Put another wideband in the tailpipe and compare. Or just swap the sensor to a brand new one and see.
    • MidnightR32
      RB20DET lean on cold start

      By MidnightR32 · Posted

      Oh, my misunderstand. When the car was running, it sounded ok, but if I gave it any gas it wanted to die but caught itself afterwards. It's very different from how it was a couple months ago when it was warmer outside. The logs show that the AFRs are better during, what I assume, is warmup enrichment. Because it's cold, and air is more dense, should I work on the enrichment bit?
×
×
  • Create New...