Strange Idle - after fuel pump swap (E85)

BossJ

Ok - so I’m coming to the experts for this one.

Here's the ISSUE: https://www.youtube.com/watch?v=XC_BoHgy2jA (not sure how to embed the video, have tried youtube / youtube hd in brackets)

Watch the first 35 seconds.


2016 370z Nismo
Z1 Cold Air Intake
FI Test Pipes
Greddy GT Exhaust

AEM’s 340LPH E85 Fuel Pump (runs strictly E85)
1050cc Injectors
Tuned by Seb (V5 Ecutek)

The Issue: For the first 5 - 10 minutes, my AFR and IDLE will be a bit wonky, as in, my AFR is pretty steady at 14.7 - Driving is normal - feels fine, BUT at idle - my AFR goes anywhere from 13-15.5 and my RPM goes from 700 (once hit 675) up to 950 and goes back and forth. This ONLY happens once or twice during the first 5-10 minutes of driving. This is cold or not, so I could drive the car for 30 minutes. Shut it off, turn it back on 15 minutes and it will happen again.

After the 5-10 minutes my idle is perfect.

What I’ve done:

Retuned with Seb
Battery Check - Completely normal.
Cleaned manifolds and throttle bodies.

Talked to the dealership and my performance shop. Dealership says everything is good. Seb says if there’s an issue (which he can’t see one) maybe it’s the WB O2 sensors.

My next step would be maybe a vacuum leak check?


Do you guys have any idea what I should look at or is this just the nature of a Z with E85 and my mods?


Thanks guys.

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2016 Pearl White 370Z Nismo (6ma) || Z1 CAI || Greddy GT X || FI Resonated Test Pipes || Ported Manifolds || Fuel Pump: aem50-1200 || 1050cc Fuel Injectors || E85 || RJM Performance Clutch || ECUTECH - SpecialtyZ (Seb)