Jump to content

Welcome to Nissan GT-R Heritage
Register now to gain access to all of our features. Once registered and logged in, you will be able to create topics, post replies to existing threads, give reputation to your fellow members, get your own private messenger, post status updates, manage your profile and so much more. If you already have an account, login here - otherwise create an account for free today!
Photo

Misfires at idle

- - - - -

  • Please log in to reply
22 replies to this topic

#1
socalaviator

socalaviator

    Stage 4 Member

  • Member
  • 447 posts
  • Joined 23-February 15
I'm trying to diagnose some misfires I have at idle and reaching out for any tips people may have. My tuner/builder is trying to help me but haven't been able to take my car to him yet.

Data logs at WOT are rock solid and spot on. Even at 50% throttle everything looks great.
Cold Idles are rock solid as well.

Once engine warms up to full operating temps is when the misfires begin. Misfires are worse in hot weather and slightly better in cooler (less than 80 degrees) weather but still present.

AFR Bank 1 is 110% to 118% when misfires are present and sometimes pegged at 120%+ . while AFR Bank 2 is usually within 5% of 100.
"Multiple/Random cylinder misfires" and "Cyl 5 Misfire" codes sometimes accompany these misfires.

The moment I rev my engine above 2000 or so rpm misfires dissapear. And the moment I start driving and apply anything more than 10% throttle misfires disappear as well.

I can provide datalogs as I have many for idle misfiring.

Edited by socalaviator, 13 October 2018 - 02:59 PM.

RD Engineering. HKS GT1000 build.

#2
socalaviator

socalaviator

    Stage 4 Member

  • Member
  • 447 posts
  • Joined 23-February 15
Fuel system : Fore Triple with Walbro 430s (the big ones) hardwired with the Ecutek module. Fore post fuel filter mounted in custom location.

Stock rails, stock FPR and stock everything else fuel related.

1700cc injectors
RD Engineering. HKS GT1000 build.

#3
Doug@WGP

Doug@WGP

    Stage 4 Member

  • Vendors
  • 2,794 posts
  • Joined 25-April 13
Pump gas or E?

Doug Ross
Owner of Weapons Grade Performance
-Northeast/Pacific Northwest Shops where we ONLY work on GT-Rs
-Owner/Builder of the 1st Ever Home Garage GT-R Drivetrain Removal
Cobb Protuner / EcuTek Tuner
-All Wheel Drive Mustang Dyno in House
doug@weaponsgradeperformance.com
Our Online Store
East Coast Location 226 N. Plains Industrial Rd, Wallingford CT 06492 203-668-4765


#4
socalaviator

socalaviator

    Stage 4 Member

  • Member
  • 447 posts
  • Joined 23-February 15

Pump gas or E?


E85 (E80 to be exact)
RD Engineering. HKS GT1000 build.

#5
Doug@WGP

Doug@WGP

    Stage 4 Member

  • Vendors
  • 2,794 posts
  • Joined 25-April 13
The tune probably just needs adjustment as ID1700 don’t idle well haha.

Doug Ross
Owner of Weapons Grade Performance
-Northeast/Pacific Northwest Shops where we ONLY work on GT-Rs
-Owner/Builder of the 1st Ever Home Garage GT-R Drivetrain Removal
Cobb Protuner / EcuTek Tuner
-All Wheel Drive Mustang Dyno in House
doug@weaponsgradeperformance.com
Our Online Store
East Coast Location 226 N. Plains Industrial Rd, Wallingford CT 06492 203-668-4765


#6
socalaviator

socalaviator

    Stage 4 Member

  • Member
  • 447 posts
  • Joined 23-February 15

The tune probably just needs adjustment as ID1700 don’t idle well haha.

Doug.  That was his first remark to me as well.  lol.

It's not a big deal really but would be nice if it didn't misfire as much.

 

Other thought is that there might be a tiny air leak in Bank 1 somewhere?


RD Engineering. HKS GT1000 build.

#7
Doug@WGP

Doug@WGP

    Stage 4 Member

  • Vendors
  • 2,794 posts
  • Joined 25-April 13
Less likely. Who’s tuning it?

Doug Ross
Owner of Weapons Grade Performance
-Northeast/Pacific Northwest Shops where we ONLY work on GT-Rs
-Owner/Builder of the 1st Ever Home Garage GT-R Drivetrain Removal
Cobb Protuner / EcuTek Tuner
-All Wheel Drive Mustang Dyno in House
doug@weaponsgradeperformance.com
Our Online Store
East Coast Location 226 N. Plains Industrial Rd, Wallingford CT 06492 203-668-4765


#8
socalaviator

socalaviator

    Stage 4 Member

  • Member
  • 447 posts
  • Joined 23-February 15

Less likely. Who’s tuning it?

Ronnie at RD Engineering.  He's been busy with builds but should be able to look at the logs this week.

I'm trying to troubleshoot in the meantime.


RD Engineering. HKS GT1000 build.

#9
Doug@WGP

Doug@WGP

    Stage 4 Member

  • Vendors
  • 2,794 posts
  • Joined 25-April 13
There’s likely nothing to troubleshoot. Set the target to 12.0 AFR at idle and a min idle RPM of 950 and see if it stops.
  • socalaviator likes this

Doug Ross
Owner of Weapons Grade Performance
-Northeast/Pacific Northwest Shops where we ONLY work on GT-Rs
-Owner/Builder of the 1st Ever Home Garage GT-R Drivetrain Removal
Cobb Protuner / EcuTek Tuner
-All Wheel Drive Mustang Dyno in House
doug@weaponsgradeperformance.com
Our Online Store
East Coast Location 226 N. Plains Industrial Rd, Wallingford CT 06492 203-668-4765


#10
socalaviator

socalaviator

    Stage 4 Member

  • Member
  • 447 posts
  • Joined 23-February 15

There’s likely nothing to troubleshoot. Set the target to 12.0 AFR at idle and a min idle RPM of 950 and see if it stops.

Gotcha. Idle RPM is definitely lower than this now and I think Target AFR is 12.7 at the moment.

 

I'm pretty sure you're right


RD Engineering. HKS GT1000 build.

#11
socalaviator

socalaviator

    Stage 4 Member

  • Member
  • 447 posts
  • Joined 23-February 15
A tiny bit more fuel was added and rpm raised 50rpm and it made the biggest difference in the world.
Target AFR remained at 12.55 as before.

The thing we still need to troubleshoot is Bank 1 is demanding 8%-10% more fuel in short-term fuel trim than Bank 2.
  • 7racer likes this
RD Engineering. HKS GT1000 build.

#12
Cicio@TSM

Cicio@TSM

    Stage 4 Member

  • Vendors
  • 1,081 posts
  • Joined 19-December 12

A tiny bit more fuel was added and rpm raised 50rpm and it made the biggest difference in the world.
Target AFR remained at 12.55 as before.

The thing we still need to troubleshoot is Bank 1 is demanding 8%-10% more fuel in short-term fuel trim than Bank 2.

 

 

That's just the stock FPR talking 


~Cicio
 
***TOP THREE TSM 1/4 MILE***
-7.37 & 198
-7.47@194
-7.59@189
***TOP THREE TSM 1/2 MILE***
-225.9 MPH
-221.3 MPH
-219.5 MPH

-OneLap of America Overall 1st Place - 2010, 2011, 2012, 2013
-TX2K13 Overall 1st Place | TX2K13 Class 2 1st Place
-Shootout 2015 Overall 1st Place & 2nd Place
-TX2K15 Class 4 2nd Place | TX2K15 Roll Race 1st Place SS
-FL2K 2015 Overall 1st Place
-TSM ELITE Plus Stock Frames @ 7.98@169
-Standing Half Mile Stock Frame Turbo Record @ 209 TSM ELITE

TopSpeedForumGTR.jpg
Call: 678-297-7770
cicio@topspeedmotorsports.com
TopSpeedMotorsports.com
**AWD Dyno Tuning
**Parts, Sales, Service


#13
240Z TwinTurbo

240Z TwinTurbo

    Stage 2.5 Member

  • Member
  • 269 posts
  • Joined 06-February 14
  • LocationCharlotte, North Carolina

That's just the stock FPR talking 

 

Curious as to how the stock FPR would affect bank balance?


  • socalaviator likes this

2006 EVO IX (601hp/462tq @ wheels Shell 93 pump gas)
2009 GTR Premium (707hp/628tq @ wheels Shell 93 pump gas / 10.24@138)
Built RB26 with no home (everything is for sale...lots of stuff)

DIY700 - 700hp on a Budget

BW S362 SXE TwinScroll Project

Curt Brown 2.15L / S362 SX-E (68mm) / EVO IX / Pump Gas


#14
Cicio@TSM

Cicio@TSM

    Stage 4 Member

  • Vendors
  • 1,081 posts
  • Joined 19-December 12

Curious as to how the stock FPR would affect bank balance?


I should say factory rails, it’s not just the regulator.

~Cicio
 
***TOP THREE TSM 1/4 MILE***
-7.37 & 198
-7.47@194
-7.59@189
***TOP THREE TSM 1/2 MILE***
-225.9 MPH
-221.3 MPH
-219.5 MPH

-OneLap of America Overall 1st Place - 2010, 2011, 2012, 2013
-TX2K13 Overall 1st Place | TX2K13 Class 2 1st Place
-Shootout 2015 Overall 1st Place & 2nd Place
-TX2K15 Class 4 2nd Place | TX2K15 Roll Race 1st Place SS
-FL2K 2015 Overall 1st Place
-TSM ELITE Plus Stock Frames @ 7.98@169
-Standing Half Mile Stock Frame Turbo Record @ 209 TSM ELITE

TopSpeedForumGTR.jpg
Call: 678-297-7770
cicio@topspeedmotorsports.com
TopSpeedMotorsports.com
**AWD Dyno Tuning
**Parts, Sales, Service


#15
socalaviator

socalaviator

    Stage 4 Member

  • Member
  • 447 posts
  • Joined 23-February 15

That's just the stock FPR talking


Cicio. Thanks for chiming in. Can you elaborate more?

Once fuel was added and rpm raised 50rpm it helped a ton. No more misfires codes but short-term fuel imbalance between bank1 and bank2 is around 8-10% difference (Bank 1 demanding more fuel)

Turning AC to ON also helps when there are misfires.

How do the stock fuel rails and FPR play into this?

Btw, all WOT runs are perfect across all measurements. Injector duties in the 80s
RD Engineering. HKS GT1000 build.

#16
socalaviator

socalaviator

    Stage 4 Member

  • Member
  • 447 posts
  • Joined 23-February 15

Curious as to how the stock FPR would affect bank balance?


Yeah now that the misfires are negligible I'm trying to figure out the reason for the short-term trim imbalance at idle. If rpms increased to about 2000rpm imbalance dissapears. Also when car is driven (under load) imbalance dissapears rather quickly and all is normal
RD Engineering. HKS GT1000 build.

#17
240Z TwinTurbo

240Z TwinTurbo

    Stage 2.5 Member

  • Member
  • 269 posts
  • Joined 06-February 14
  • LocationCharlotte, North Carolina
Have you performed a bank balance?

2006 EVO IX (601hp/462tq @ wheels Shell 93 pump gas)
2009 GTR Premium (707hp/628tq @ wheels Shell 93 pump gas / 10.24@138)
Built RB26 with no home (everything is for sale...lots of stuff)

DIY700 - 700hp on a Budget

BW S362 SXE TwinScroll Project

Curt Brown 2.15L / S362 SX-E (68mm) / EVO IX / Pump Gas


#18
socalaviator

socalaviator

    Stage 4 Member

  • Member
  • 447 posts
  • Joined 23-February 15

Have you performed a bank balance?


Not since my last POS service but that was way before my build.

Is this something I can do at home with Ecutek?
RD Engineering. HKS GT1000 build.

#19
240Z TwinTurbo

240Z TwinTurbo

    Stage 2.5 Member

  • Member
  • 269 posts
  • Joined 06-February 14
  • LocationCharlotte, North Carolina

I should say factory rails, it’s not just the regulator.

 

same question...how do factory rails/FPR affect bank balance?


Edited by 240Z TwinTurbo, 26 October 2018 - 10:34 AM.

2006 EVO IX (601hp/462tq @ wheels Shell 93 pump gas)
2009 GTR Premium (707hp/628tq @ wheels Shell 93 pump gas / 10.24@138)
Built RB26 with no home (everything is for sale...lots of stuff)

DIY700 - 700hp on a Budget

BW S362 SXE TwinScroll Project

Curt Brown 2.15L / S362 SX-E (68mm) / EVO IX / Pump Gas


#20
240Z TwinTurbo

240Z TwinTurbo

    Stage 2.5 Member

  • Member
  • 269 posts
  • Joined 06-February 14
  • LocationCharlotte, North Carolina

Not since my last POS service but that was way before my build.

Is this something I can do at home with Ecutek?

 

I believe ECUTek has that feature so yes, you should be able to perform it.  Every time I pulled the intake manifold or TB's I had STFT issues and had to perform a bank balance, which resolved it.


2006 EVO IX (601hp/462tq @ wheels Shell 93 pump gas)
2009 GTR Premium (707hp/628tq @ wheels Shell 93 pump gas / 10.24@138)
Built RB26 with no home (everything is for sale...lots of stuff)

DIY700 - 700hp on a Budget

BW S362 SXE TwinScroll Project

Curt Brown 2.15L / S362 SX-E (68mm) / EVO IX / Pump Gas





0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users