Hey dovla, have you tried the latest Cipher v1.02 and the wideband conversion?

 

Just read this whole thread for the 1st time. Very interesting about the the differing AF ratios between banks.
When the ATI procharger was released with a crude fueling remedy & no timing adjustment there were quite a few motor blow ups & it was always the passengers side pistons that were damaged, useually the rear ones.
I detonated my own mildly modified NA motor on the track by running the fuel tank to low & the motor was hesitating from fuel starvation on hard right corners.
When the motor was pulled down the 3 pistons on the RH bank showed detonation damage. The left ones were OK.

 

Hmm that doesn't sound very good.

 

According to Service Manual (Edition: October 2003 Revision: February 2004 Publication No. SM4E-1V35U9), bank 1 is passenger side and bank 2 is driver side. So, in post #11, I made mistake writing “the passenger bank is almost always leaner” when in fact bank 2 or driver side is almost always leaner. Sorry.
And yet while on 17 degrees timing, and with half a tank of 91-octane gasoline and half a tank of 93-octane gasoline I received P0303 DTC, No. 3 cylinder misfire detected, which is on the passenger side.

MechEE, I was looking for wideband V to AF conversion in Cipher v1.02 but didn’t see it in the list of parameters to monitor. How do you access it?

I just lost HD partition (due to bad sector) on laptop that I am using as CarPC so will have to rebuilt entire CarPC, what a pain.

 

Dovla and MechEE,

You both have the REVUP correct? And you both found an imbalance?

This suggest whatever is causing the imbalance in not related to flow imbalance caused by the upper plenum being too close to the lower plenum. The revup lower collector fixed that problem.

Unfortunatly there is some other unknown cause.

I doubt it could be from pressure drop in the fuel rails because their flow diameter is about 1/2".... which is several orders of magnitude more than the cumulative flow area of the injector orifice diameters.

Something else is going on...

 

If your tank was low enough that it was flowing frothy (champagin) fuel to the engine, it would make sense that bubbles would drift to the side in which you are turning.

You would be getting frothy or corrupted fuel on the right fuel rail and clean fuel on the left rail.

 

I have no REVUP. Mine is 2004.5 MT coupe with 1/2" copper spacer and C. cats.

 

Then you certaintly don't have a pressure imbalance either.

EDIT: (maybe there is?)

 

Details are in the Cipher_User_Guide_v1.02.pdf in the UpRev folder, section 12.7. Basically you have to go to the "options" menu, click "Edit" under Wideband Conversion, click Add sensor (leave the values default) and name it, then click Add ECU and type in the ECU number corresponding to your car (that you get in the connect screen). Then you will have a new parameter listed for possible logging: "Calculated A/F".

 

Hmm what exactly makes it a 2004.5? I figured 2004.5 suggested it had the interior and engine of the 2005+.

 

Hmm yes given the identical injection times, and assuming similar pressures in both rails, there must be some physical flow imbalance between banks. It's strange that Nissan doesn't correct for this in closed loop. I guess if you floored it all day long it might trim the banks separately, but as soon as you drove around town for a while it would trim it back out. Flow appears to be equal for low loads. Based on the differences in AFR, it looks like bank 2 is getting ~4% more air at WOT.

 

When I was ordering G35 Coupe Serv.Man. there were two versions for 2004 coupes: VINs up to 8 and VINs 8+.

No interior changes from 2004. Engine, don’t know - WB sensors

 

If anyone is still interested, I finally had WB sensors switched and there was no change, B2 is still leaner.

 

Dovla,

Good data.

Now that the WB sensors and fuel injector %duty cycles has been eliminated, there is only two other significant variables (I know of) that could readily cause this.

First) A difference in intake cam angles.

Even if they read as ientical as seen by the ECU, the cam angle sensors may not have identical calibration.

Second) A difference in lower plenum flow charecteristics.

You know of the MREV+ modification I recently installed on a normal VQ engine that made gains?.... It reduced the flow restriction on only specific intake runners. Some runners have more pressure drop at the mouth of the inlet than others even if the upper plenum is raised up.

It may be related to this.

 

In first ~40% of the log samples, INJ PULSE B1 is longer than INJ PULSE B2 (from 0.1 to 0.3 ms) – probably insignificant and perhaps within tolerance of either ECU or Cipher. But comparing with other logs I see same trend where B1 have longer pulse at the beginning of the log.


Timing is showing similar trend.


I have no clue if ideally B1 and B2 timing and/or pulse rate should be same.

I am eagerly waiting for your MREV+ with ½” spacer dyno and hoping that beside some gains, AFR B1 vs B2 will be more equalized