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Subject Thanks for the reply!
     
Posted by outkaZTT on December 19, 2018 at 9:54 AM
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In Reply To Re: Help diagnosing A/F ratio differential between passenger posted by MagicMike on December 18, 2018 at 06:54 PM
     
Message I'm the owner of the Z in question.

The AFR difference between the banks is present mostly at WOT although there is a slight difference at idle as well.

I am running an off the shelf SZ E85 chip with map selector. Prior to having my injectors cleaned and flow tested I had to add a significant amount of fuel through my AFC (about 10-12% through the entire rpm range) in order to get the AFRs down to mid/high 11's on the driver side bank. I was also seeing up to a full point difference in AFR between the driver/passenger banks (eg: 11.5 on driver bank would equate to about 10.5 on passenger bank). Since the cleaning I have been able to dial out all of the extra fuel from the AFC but I am still seeing about a .5-.8 difference in AFR between the two banks.

Below are things I've checked and/or noticed. My profile should also be up to date.

*As far as I can tell my TBs are synched and both butterflies are completely horizontal in the TB when fully opened

*I have performed multiple boost leak tests and there is only a tiny pinhole leak at the orange rubber seal on the side of the passenger TB where the linkage is. Its so small that I highly doubt it has any affect on the issue at hand

*No sign of exhaust leaks before the o2 sensors which would skew the readings

*Selin translator is set to Average

*Bypassed my AFC and no change in AFR discrepancy

*Passenger o2 sensor was older and erratic so I replaced with a new sensor. Driver side o2 has less than 1k miles on it (added when I swapped to E85)

*Increased my base fuel pressure (Turbosmart 800 FPR) to around 56psi at idle to help with the previous lean condition at WOT, no change in the AFR discrepancy

*New Walbro 485 pump with FPCU bypass

*Wastegates were tested and balanced when the turbos were installed

*My AFR at idle is so lean that I have to add 20% fuel at idle to get the AFRs to 14.7-14.9. This is really strange to me and not sure of the cause

At this point we are leaning toward the issue maybe being the rails being installed in serial. I know generally only high horsepower cars have needed parallel setups but we think the extra demand of E85 may be contributing to needing the parallel setup. Thoughts? I was thinking of buying some new fuel line and briefly changing the flow through the rails so that the driver side is fed first, then the passenger side to see if the AFR discrepancy reverses. I'm guessing there would be no issues or risk in doing this?

Thanks in advance for any help!

     
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