Idle misfire troubleshooting today. Some progress
02-28-2009, 11:05 AM
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Idle misfire troubleshooting today. Some progress
Background:
I've had idle misfires on my ASP stage 3 since day one (42# injector file) that triggers a CEL. Not good for state inspection and idle could be smoother but I don't have any other driveability issues so I kinda let it slide.
Checked today w/Vag showing mostly cyl #1 (50+) with a few on #6 (~10) during a counting period
Over the last 4 yrs I've made the following changes/observations:
Swapped to 42lb greentops/GIAC X/RS4 MAF HomeBrew for more boost (My early ASP file only ran 17psi). Misfires went away for the year I was running this HB set-up.
Got an updated S3 file with mo boost from ASP in '06 and put the (delphi?) 42#ers back in. Swapped stock fuel pump for Walbro as well. Misfires returned.
Time for fresh platinum plugs in 07 (last changed in 05). Misfires remain.
Today I started adding idle torque offset via lemmi. This has gotten me from 60+ misfires in a counting period down to 20-25. +30 idle tq offset moved my idle tq from ~17 to ~20. While doing this, I noticed my idle fuel trim increased from -0.8 to -0.4
Does adding idle torque just richen up the A/F?
A lot of searching the internet re idle misfires points to "lean" misfires which can come from vacuum leaks or faulty injectors.
Anyway, my thought at this point is that this isn't ignition related but mixture related. Added idle TQ seems to have improved the symptoms (to where I don't have a CEL) but I'm not convinced the problem is "fixed".
So once my engine cools, I'm swapping injectors around and replacing the lower injecor O-rings with ones from my stock injectors. Hope this resolves the problem!
I've had idle misfires on my ASP stage 3 since day one (42# injector file) that triggers a CEL. Not good for state inspection and idle could be smoother but I don't have any other driveability issues so I kinda let it slide.
Checked today w/Vag showing mostly cyl #1 (50+) with a few on #6 (~10) during a counting period
Over the last 4 yrs I've made the following changes/observations:
Swapped to 42lb greentops/GIAC X/RS4 MAF HomeBrew for more boost (My early ASP file only ran 17psi). Misfires went away for the year I was running this HB set-up.
Got an updated S3 file with mo boost from ASP in '06 and put the (delphi?) 42#ers back in. Swapped stock fuel pump for Walbro as well. Misfires returned.
Time for fresh platinum plugs in 07 (last changed in 05). Misfires remain.
Today I started adding idle torque offset via lemmi. This has gotten me from 60+ misfires in a counting period down to 20-25. +30 idle tq offset moved my idle tq from ~17 to ~20. While doing this, I noticed my idle fuel trim increased from -0.8 to -0.4
Does adding idle torque just richen up the A/F?
A lot of searching the internet re idle misfires points to "lean" misfires which can come from vacuum leaks or faulty injectors.
Anyway, my thought at this point is that this isn't ignition related but mixture related. Added idle TQ seems to have improved the symptoms (to where I don't have a CEL) but I'm not convinced the problem is "fixed".
So once my engine cools, I'm swapping injectors around and replacing the lower injecor O-rings with ones from my stock injectors. Hope this resolves the problem!
02-28-2009, 12:49 PM
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Log blocks 1, 4, 14 (b5qship method) to get good picture of misfires.
I had some issues with random misfires (ASP 60# code). Was able to get rid of CEL by increasing ITO and RPM. See pics below. However, after all this found out that O2 sensors never came ready, so had to get a SW update to fix.
Initial Misfire Situation
<img src="http://www.tlcpropmgmt.com/audi/ASP_misfires_initial_040108.jpg">
After +20 ITO, +80 RPM
<img src="http://www.tlcpropmgmt.com/audi/ASP_misfires_20ITO_80RPM_040208.jpg">
Bruce
Initial Misfire Situation
<img src="http://www.tlcpropmgmt.com/audi/ASP_misfires_initial_040108.jpg">
After +20 ITO, +80 RPM
<img src="http://www.tlcpropmgmt.com/audi/ASP_misfires_20ITO_80RPM_040208.jpg">
Bruce
02-28-2009, 04:19 PM
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Welp, got my answer. Misfires moved with the injectors.
Cleaned and inspected all the O-rings. Look good and fit tight. Cleaned the manifold where they fit in. No scratches or debris.
Cyl # 1 misfires moved to #2
Cyl #6 misfires moved to #4
same counts (#2 more than #4)
right where I moved the injectors. I guess these two are weak at very short dc.
IdTqOf +30 is keeping them down below the threshold for now.
Saw your post re: LTFTs. Sorry, no idea how to help. GL
Cyl # 1 misfires moved to #2
Cyl #6 misfires moved to #4
same counts (#2 more than #4)
right where I moved the injectors. I guess these two are weak at very short dc.
IdTqOf +30 is keeping them down below the threshold for now.
Saw your post re: LTFTs. Sorry, no idea how to help. GL
02-28-2009, 04:23 PM
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Has anyone talked to ASP about this?
I have had a rough idle since my car came off the dyno 2 years ago for a custom tune, but the car runs excellent. My CEL's (LTFT bank 2) started a few weeks ago. I tracked down a few small vacuum leaks by the TBB but misfires remain. After STFA'ing (plugging in "misfire" is not for the faint of heart!) I found some great info and ended up watching the misfires (over 150 during any period) disappear when I pushed in the clutch pedal.
During my quest for misfire liberation I had changes plugs (a few of the Platin gaps were a little large after 4k miles of stage 3 goodness), swapped ICM's, rotated coil packs, Changed o2's, sacrificed 2 whole chickens, and nearly went insane hearing mystery vaccum leaks that may or may not still be there (worm gear clamps FTL). Car still drives great mind you.
More than half of my misfires come from cylinder 2, so, I felt like there could be a hardware problem. I started to wander about a fuel injector, but misfires go away with clutch in. Small note here: while looking to find something bigger than a chicken to sacrifice, I unplugged o2's electrical connectors and plugged in a new set of Zoldman's that I set aside for a rainy day and misfires disappeared!?! After install, misfires back. Car runs great.
Hmmm, maybe if I get the neighbor's chocolate lab that barks at 5am like clockwork, I could kill 2 birds with one stone, err wrench.
Is this a mapping issue at idle as some have suggested? I'm sure Mark could help.
Anyways.
Lessons learned: 1) STFA is great, but only if you are mentally stable 2) All of us are smarter than one of us 3)Hanging parts before correctly diagnosing will only help you empty your wallet 4) Buy nice or buy twice 5) The neighbors don't take kindly to you feeding their dog Nyquil 6) My misfires are still there with the clutch out 7) My cars runs great!
2000 Audi S4 34,xxx miles
Clearanced, polished K04's
ASP fueling w/ custom tuning
ASP mani's, downpipes, cat-back
AWE intercoolers
Vast kevlar clutch
Vast phenolic spacers
Blood of 2 chickens
Toyguy shifter
Stoptech 332
ECS slotted s8 rears
PSS9 coilovers with homebrew linear rear spring conversion - I love it!
Neuspeed rear sway
TSW Cataluya's
RS4 Ghetto bumper conversion - what a pain in the ***!
1 chocolate lab incisor - and the scars to show for it.
A bunch of other crap that would take too long to list.
What I would rather be doing instead of tracking down misfires.
<img src="http://pictureposter.audiworld.com/68115/montana2007_231.jpg">
During my quest for misfire liberation I had changes plugs (a few of the Platin gaps were a little large after 4k miles of stage 3 goodness), swapped ICM's, rotated coil packs, Changed o2's, sacrificed 2 whole chickens, and nearly went insane hearing mystery vaccum leaks that may or may not still be there (worm gear clamps FTL). Car still drives great mind you.
More than half of my misfires come from cylinder 2, so, I felt like there could be a hardware problem. I started to wander about a fuel injector, but misfires go away with clutch in. Small note here: while looking to find something bigger than a chicken to sacrifice, I unplugged o2's electrical connectors and plugged in a new set of Zoldman's that I set aside for a rainy day and misfires disappeared!?! After install, misfires back. Car runs great.
Hmmm, maybe if I get the neighbor's chocolate lab that barks at 5am like clockwork, I could kill 2 birds with one stone, err wrench.
Is this a mapping issue at idle as some have suggested? I'm sure Mark could help.
Anyways.
Lessons learned: 1) STFA is great, but only if you are mentally stable 2) All of us are smarter than one of us 3)Hanging parts before correctly diagnosing will only help you empty your wallet 4) Buy nice or buy twice 5) The neighbors don't take kindly to you feeding their dog Nyquil 6) My misfires are still there with the clutch out 7) My cars runs great!
2000 Audi S4 34,xxx miles
Clearanced, polished K04's
ASP fueling w/ custom tuning
ASP mani's, downpipes, cat-back
AWE intercoolers
Vast kevlar clutch
Vast phenolic spacers
Blood of 2 chickens
Toyguy shifter
Stoptech 332
ECS slotted s8 rears
PSS9 coilovers with homebrew linear rear spring conversion - I love it!
Neuspeed rear sway
TSW Cataluya's
RS4 Ghetto bumper conversion - what a pain in the ***!
1 chocolate lab incisor - and the scars to show for it.
A bunch of other crap that would take too long to list.
What I would rather be doing instead of tracking down misfires.
<img src="http://pictureposter.audiworld.com/68115/montana2007_231.jpg">
02-28-2009, 05:36 PM
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I've talked to them but never brought my car down there to have them look.
Mark didn't have any suggestions other than to come down to the shop. I haven't really bugged him about it that much and I live 80 mi away.
When you press in the clutch, the ECU increases idle torque (whatever the hell that means). You might try adding Idle torque offset w/ Lemmiwinks. Go up in increments of 10 and watch VAG block 014. My total counts dropped but didn't go away. Others have posted this as a fix which is why I tried it.
What cylinders (other than #2) do you see them on? Do you have high counts on one particular cyl on the opposite bank? i.e. 4, 5, or 6?
I'm thinking about moving the injectors from misfiring cylinders to the same side of the engine.
As I mentioned below, I suspect my injectors don't have consistent fuel delivery across all 6 at idle and the leaner ones misfire. Maybe putting them on the same bank will let the ECU sort of compensate.
Any leads on where I can find live chickens?
When you press in the clutch, the ECU increases idle torque (whatever the hell that means). You might try adding Idle torque offset w/ Lemmiwinks. Go up in increments of 10 and watch VAG block 014. My total counts dropped but didn't go away. Others have posted this as a fix which is why I tried it.
What cylinders (other than #2) do you see them on? Do you have high counts on one particular cyl on the opposite bank? i.e. 4, 5, or 6?
I'm thinking about moving the injectors from misfiring cylinders to the same side of the engine.
As I mentioned below, I suspect my injectors don't have consistent fuel delivery across all 6 at idle and the leaner ones misfire. Maybe putting them on the same bank will let the ECU sort of compensate.
Any leads on where I can find live chickens?
03-01-2009, 07:28 AM
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Yep. Circa 2006 OTS tune. You have info on the spray pattern?
<center><img src="http://www.racetronix.com/product/Injectors/621031.jpg"></center><p>I beleive these are the injectors<ul><li><a href="http://www.racetronix.com/621031.html">http://www.racetronix.com/621031.html</a></li></ul>
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03-02-2009, 06:10 PM
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Found it. Yikes, my old greentops look (and idled) better
<center><img src="http://tychl.txf.com/mototron/injectorpatternsMar2006.jpg"></center><p>
42 lb bluetops in the pic<ul><li><a href="https://forums.audiworld.com/s4/msgs/2315255.phtml">https://forums.audiworld.com/s4/msgs/2315255.phtml</a></li></ul>
42 lb bluetops in the pic<ul><li><a href="https://forums.audiworld.com/s4/msgs/2315255.phtml">https://forums.audiworld.com/s4/msgs/2315255.phtml</a></li></ul>
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