Jump to content
SAU Community

Recommended Posts

Hi Guys,

Got a problem which has reared it's head in the last week. Car idles extremely rough, sorta like a high RPM missfire. hard to explain, but sorta sounds like a WRX (constant pop) and the whole car shakes badly. Car got tuned around 6 months ago.

has Power FC, Z32, 850cc sard's, Splitfire coilpacks, HKS twin spark, upgraded turbo and external gate and Walbro Fuel pump with re-wired relay.

Swapped out the coilpacks with a brand new set as a precaution, regapped plugs to .7 to rid it of any chance of missfire. Changed fuel pump relay, changed Coil pack loom and swapped Ignitor pack.

Checked the Z32 wiring tonight and noticed that going by PaulR33's wiring picture that when the AFM was installed, the signal ground and 12v ground were mixed up. swapped them and the same problem remains. What are the odds of this mix up causing an AFM failure or PFC failure?

Only thing i haven't done is swap the fuel pump over, sounds a little funny when it's priming, but was looked at by a mechanic and he said it was working. another possibility??

Any help is much appreciated.

Cheers

Link to comment
https://www.sau.com.au/forums/topic/313195-idle-problem-on-r33-gtst/
Share on other sites

Hi Guys,

Got a problem which has reared it's head in the last week. Car idles extremely rough, sorta like a high RPM missfire. hard to explain, but sorta sounds like a WRX (constant pop) and the whole car shakes badly. Car got tuned around 6 months ago.

has Power FC, Z32, 850cc sard's, Splitfire coilpacks, HKS twin spark, upgraded turbo and external gate and Walbro Fuel pump with re-wired relay.

Swapped out the coilpacks with a brand new set as a precaution, regapped plugs to .7 to rid it of any chance of missfire. Changed fuel pump relay, changed Coil pack loom and swapped Ignitor pack.

Checked the Z32 wiring tonight and noticed that going by PaulR33's wiring picture that when the AFM was installed, the signal ground and 12v ground were mixed up. swapped them and the same problem remains. What are the odds of this mix up causing an AFM failure or PFC failure?

Only thing i haven't done is swap the fuel pump over, sounds a little funny when it's priming, but was looked at by a mechanic and he said it was working. another possibility??

Any help is much appreciated.

Cheers

start with a compression test...

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

    • I have copied the images in the original post from photobucket to the SAU servers to make sure they stay available.
    • Mate you saved be from dying in the Perth summer. AC wasn't changing direction and just going into diagnostics mode fixed it. You're a legend and I would shout you a beer if I could!
    • Unfortunately effort gone to waste, you will have substantial issues with how the manifold and wastegate have been integrated. You would be so much better off with a modified stock manifold like this: https://hypergearturbos.com/product/rb25detexgatedmanifold/   OR literally just getting a off the shelf Sinco or 6Boost manifold as myself and others have mentioned.  
    • Yuck. But it's kinda the same principle, moving timing around to make car run bad but sound good.... I went for a more spirited tuning drive to iron out a few things. Car no longer stalls, and it loved to dip RPM low when you clutch in. After tuning this (and the 4-5 tables that HPTuners/LS1 OEM ECU wants for idle air correction) it's now behaving somewhat normal. All expected because there's a new TB, new Intake manifold and that new TB which is 102mm vs 78... has an entirely different IAC passage which is smaller because ????? Unfortunately at this point I went to make further fine tuning changes to avoid it flaring up, you know... _tuning_ the HPTuners dongle died. Well to be more accurate - The USB cable died in a fashion that anyone who has ever charged a phone will recognize. After the app demanding I resync it 50 or so times (which all 'succeeded' but all failed) the device does not want to sync and I've logged a ticket with support to see if it's fixable. US Support said it was a 'storage issue' but after removing the SD card inside it and formatting it/fixing it the issue does persist. Unfortunately usually the fix is "Turn in your old dongle and pay $700 for the upgraded one" it's cheaper because I get some free licence credits I unfortunately don't need. However I'm 10 minutes down the road from HP Tuners AUS/VCM so at least I won't need to post it, and logged a new ticket for support over here. Definitely drives different. My SOTP dyno believes it's probably making 310-320kw instead of the 280 before.  It scrambles for traction a little now whereas it previously different. It drives like a bigger cam car up top even though the cam is smaller, likely due to the cam not being advanced 6 degrees. The timing is deliberately low and the fuel is very rich so who knows if this will improve on the dyno. It may, imperceptably. Also funny is removing the pineapples definitely makes the car squat more and axle tramp less. So this behavior of having more top end, squatting more, and scrabbling for traction more makes me think = more power. But I could have just been sitting on the threshold of that kind of behavior before. Time will tell if my butt dyno is calibrated right. I need the exhaust leaks fixed before dyno tune for obvious AFR related reasons - I repositioned the pipes but I'm not confident it's fully sealed even if it is better. At least the car does drive around while I cannot tweak/tune it for now. And I have aircon again. medium success!
×
×
  • Create New...