Running lean on only one Bank

[Lou02stang]

I am having a problem tuning my car with SCT Pro Racer Advantage and livewire for Datalogs. When I do a idle datalog my STFT are perfect on passenger side bank 1 and on bank 2 it is differentiated lean by 10-13 pts I checked for exhaust leaks and smoked for vacuum leaks seams like 100 times. I had injectors flow matched and also swapped them side to side with no change. I also swapped o2 sensors side to side with no change. Sometimes When I do a idle log the tune is spot on from bank to bank then if I shut the car off and start a new log 10min later the tune is off again.. WTF. I have a 2v 4.75 MMR 750 with a On3 single turbo 70lb Siemens injectors twin 320 pumps upgraded wiring and FPDM. I have Edelbrock fuel rails with Vic Jr intake My returnless setup fuel is Plummed with 8an the following way

So fuel is fed from
factory line with regulator in to
The p/s rear fuel rail to
p/s front rail out to
crossover to
Fuel rail pressure sensor on d/s front rail
Then it feeds rest of d/s rail

Could this setup be efecting the tune because the FRPS isn’t getting a chance to
Read the pressure on bank 2 rail because it is before the rail. I currently have the factory fuel regulator still do I eliminate that?

 

[01yellercobra]

If you're running a returnless system why do you have a regulator in place? Or are you talking about that chrome thing by the firewall? If so that's not a regulator. It's to dampen the fuel pulses going into the rails. I didn't know they made a set of 70lb injectors. When I ran my 80's I would get weird things at idle sometimes, but chalked it up to the injectors from what I read.

Is your bypass and wastegate vented to atmosphere?

 

[Lou02stang]

Returnless system and yes that is a Typo I have 60lb Siemens. I was talking about the chrome thing by firewall thought it was a weird to have a factory regulator looks just like one tho. Wastegate and bypass both vented to atmosphere. My Innovate wide band on the downpipe is reading almost perfect on idle 14.7-15.0

 

[Lou02stang]

What do you think about where that fuel rail pressure sensor is I feel like it should be moved to the end of the fuel feed so it reads pressure After BOTH rail are fed rather then my current setup of reading after only 1 side is fed

 

[decipha]

a picture of your fuel setup may help

 

[Lou02stang]

It’s in my 1st post here it is again

Thanx

Pin by Lou Donello on On3 Turbo 2V 4.6 | Pinterest

 

[Lou02stang]

This is how I think it should be

Pin by Lou Donello on On3 Turbo 2V 4.6 | Pinterest

 

[Lou02stang]

Pic of my setup

Pin by Lou Donello on On3 Turbo 2V 4.6 | Pinterest

 

[decipha]

im referring to an actual photo

 

[Lou02stang]

See below

 

[Lou02stang]

 

[Lou02stang]

FIXED!!!!

View attachment 1558012

I had a friend poke around with MAPP gas and found a vacuum leak at the rear ok intake plenum. Took the gasket out and just RTV it and short term fuel trims are perfect 1.00. O2 volts are off from bank to bank is that normal?

 

[01yellercobra]

Your STFT's shouldn't be straight 1.00. They should be fluctuating up and down. It's how the computer works. It's a constant correction.

 

[Lou02stang]

So what is goin on I idle logged for 2 minutes and it was 1.00 for entire time so does that mean it is running rich? O2 sensors voltage was fluctuating and making corrections the entire time stft stayed at 1.00

 

[01yellercobra]

The voltage fluctuating is a good thing. They're supposed to do that. If the STFT's never moved you likely picked the wrong PID. There should be a couple to choose from.