VQ35de uneven bank AFR (Evidence inside!)

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Dec 1, 2010 | 09:04 PM
  #41  
Quote: did u do another compression test yet
Nah for what? I dont plan to either. not anytime soon. no need
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Dec 1, 2010 | 09:08 PM
  #42  
Quote: Yeah I just use a laptop to log/tune, i dont tune by looking at the gauge (not really recommended unless ur going for a real rough tune and dont have laptop at hand.)
np bro, any time, anytime
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Dec 1, 2010 | 09:16 PM
  #43  
I'm gonna have to see if AEM has any standalone software to run two UEGOs/two gauges and then just tune off of the Ultimate, I'd rather not go Innovate and toss what I have.
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Dec 1, 2010 | 10:39 PM
  #44  
SW FTW!! no seasons there, all year round baby..

any one know what they may charge to flow bench test an IM, maybe worth looking into.
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Jan 16, 2011 | 12:25 PM
  #45  
do 3.0DE and DEK have the same problem ?
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Jan 16, 2011 | 10:02 PM
  #46  
Really doubt it
Quote: do 3.0DE and DEK have the same problem ?
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Jan 17, 2011 | 09:47 AM
  #47  
I think we have to chack all 3.0's
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Jan 26, 2011 | 07:58 AM
  #48  
THE **** MISFIRE IS GONE!!!!! (sorry for caps, im screaming lol)

So I was driving on the highway, didnt have any intentions to floor it or anything was just chilling (it was a 40min drive), so I descided, you know what! let me just do it, I went WOT and didnt feel a SINGLE hicup, nothing! I havent felt a smooth 3rd gear pull since almost a year ago lol. I couldnt believe it, so I pulled out the laptop and logged another run, everything has perfectly straight curves, timing, afr, inj, maf input. Was freaking awesome! Was actually mad at first lol, i was like "wtf your supposed to be misfiring damit!!".

Now, possible solutions, i have no idea. Recently adjusted my TPS (i have always had it on the high side of specs so i brought it down a lil bit, also plugged in the IAT sensor and have it laying in the engine bay (before wasnt plugged at all). Thats pretty much it, oh and AFR are in the high 11 low 12, so perfect.
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Jan 26, 2011 | 01:26 PM
  #49  
Good news streetz!

Question, are you still using the converted e-tb? Or did you end up going with the pathfinder unit?

Also, If im not mistaken, running with the IAT unplugged causes the ECU to pull timing similar to not having the KS plugged in at all. I've been meaning to log this to confirm 100% though. Could too much timing being pulled cause misfires in an application such as yours where alot of fuel (compared to stock) needs to be burned off?
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Jan 26, 2011 | 01:32 PM
  #50  
Quote: Good news streetz!

Question, are you still using the converted e-tb? Or did you end up going with the pathfinder unit?

Also, If im not mistaken, running with the IAT unplugged causes the ECU to pull timing similar to not having the KS plugged in at all. I've been meaning to log this to confirm 100% though. Could too much timing being pulled cause misfires in an application such as yours where alot of fuel (compared to stock) needs to be burned off?
I thought about the timing being too low as well, but its not so it ruled it out. As for the IAT causing low timing, nah I have always had it disconnected and I get full timing. I still have a stock 3.5 converted TB.
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Jan 26, 2011 | 03:31 PM
  #51  
congratz, now hit the track and dyno before it comes back
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Jan 26, 2011 | 04:01 PM
  #52  
Quote: congratz, now hit the track and dyno before it comes back
lol why you gotta be negative lol. Most likely I will dyno before going to the track, this semester is tough and busy so I wont be dedicating much time to the car except small things here and there, maybe random vid's or something. And now I have a long commute for an internship so I cant risk messing it up lol although I should be putting up the boost back to high teen's again soon.

I have also changed the mixture of my injection, I am now using more water than meth, probably like 70/30, reason being is that I believe my setup develops too much heat due to the 2" piping (I could be wrong), so the added water will take care of that, usually the rule of thumb is if your IC piping setup is not efficient then more water is needed, if IC piping setup is very efficient then very little to no water would be needed (this is based on mad research i have done over the years lol)
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Jan 26, 2011 | 06:57 PM
  #53  
Quote: lol why you gotta be negative lol. Most likely I will dyno before going to the track, this semester is tough and busy so I wont be dedicating much time to the car except small things here and there, maybe random vid's or something. And now I have a long commute for an internship so I cant risk messing it up lol although I should be putting up the boost back to high teen's again soon.

I have also changed the mixture of my injection, I am now using more water than meth, probably like 70/30, reason being is that I believe my setup develops too much heat due to the 2" piping (I could be wrong), so the added water will take care of that, usually the rule of thumb is if your IC piping setup is not efficient then more water is needed, if IC piping setup is very efficient then very little to no water would be needed (this is based on mad research i have done over the years lol)
good to know I plan to use alittle meth if I get this evo 8

good luck, high teen 20psi sound like a nice round #
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Jan 28, 2011 | 08:08 PM
  #54  
17psi TUNED!, MAF voltage at 8psi was 4.50s, at 17psi voltage was about 4.90, looks like im getting close to maxing out the Z32 maf
also output duty cycle is on average at 73% with fuel pressure im assuming at 60psi.
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Jan 28, 2011 | 09:26 PM
  #55  
You come to the track on March 13th for NSCRA.. At PBIR
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Jan 28, 2011 | 11:04 PM
  #56  
Quote: You come to the track on March 13th for NSCRA.. At PBIR
i'll see what i can do, iv never been to done of those events, would be cool to watch.
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Jan 29, 2011 | 06:53 AM
  #57  
Quote: i'll see what i can do, iv never been to done of those events, would be cool to race.
Thought so...
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Jan 23, 2012 | 05:23 AM
  #58  
So... the mystery remains. Now that I have a Z33 manifold (mrev2), I still have uneven bank AFR's. Not considering this a big deal but just some facts I wanted to put on this thread so it does not mislead peeps.
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Jan 23, 2012 | 08:10 AM
  #59  
^^^ Hmm strange. I am running a similar set-up and my a/f between banks is pretty much dead even. This is using the Z33 manifold and a spacer.

SurraTT also has about a 0.5 variation between banks though with his 7th gen vq35.
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Jan 23, 2012 | 09:46 AM
  #60  
Yep, im noticing up to .5 difference on my 7th gen VQ35. Its normal im guessing, but since the haltech can tune for this id like to have them dead even.
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Jan 23, 2012 | 11:57 AM
  #61  
Quote: Yep, im noticing up to .5 difference on my 7th gen VQ35. Its normal im guessing, but since the haltech can tune for this id like to have them dead even.
Ah, good info. Yeah I think this might apply to all VQ engines.
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Nov 3, 2014 | 06:58 AM
  #62  
Updating for documentation.

New discovery, it turns out that in my front bank, all exhaust valves leak. Rear bank, NO exhaust valves leak. This clearly shows why there was a difference in AFR.
Also the rear bank looks way more worn than the front, the pistons in the front look almost new with just a haze of bronze over them while the rear have black/carbon on them, so you can tell that the rear bank was producing more power, hence the higher compression.

The cause of this is still a mystery but once I put it back together with fresh rings and valves fix. I will tune both banks individually from day one.
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Nov 4, 2014 | 05:48 AM
  #63  
so you just going to get heads or get a valve job
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Nov 7, 2014 | 10:19 AM
  #64  
Quote: so you just going to get heads or get a valve job
going to make sure the valves arent bent and just fix it myself, going to try to lap them with lapping compound to see if they get fixed. if not then going to need new valves. Also going to change valve stem seals
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Nov 7, 2014 | 03:55 PM
  #65  
Quote: Updating for documentation.

New discovery, it turns out that in my front bank, all exhaust valves leak. Rear bank, NO exhaust valves leak. This clearly shows why there was a difference in AFR.
Also the rear bank looks way more worn than the front, the pistons in the front look almost new with just a haze of bronze over them while the rear have black/carbon on them, so you can tell that the rear bank was producing more power, hence the higher compression.

The cause of this is still a mystery but once I put it back together with fresh rings and valves fix. I will tune both banks individually from day one.
I thought I read somewhere also that this happens to the 3.5. Been checking out your recent videos, nice! Hope you get it running soon.
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Nov 8, 2014 | 10:56 AM
  #66  
What pistons are you using?
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