Question about commanded AFR changing???

[lainez11]

ok so yes I am new to tuning but not new to engines, I have a lq9 with ported 243 heads, 408 ci, 102 mm tb and high rise intake, with a TSP torquer v4 cam on a 111 lsa. I fell like I have a somewhat decent tune car runs and idles but with part throttle car surges up and down... looking at my log I noticed when surging I noticed the Commanded AFR was 14.6 and would switch to 12.19 and go back and forth until I let off the throttle?????? I must be missing something but cant quite figure it out. I thought it was a airflow issue but why would it command to 12.19?? any help or ideas would be greatly appreciated!!! I'll try to post a log later today

[5FDP]

Sounds pretty straight forward to me.

You likely have power enrichment, cat over temp or a cat test being enabled.

If PE is setup to where it's going to dip and an out at part throttle, this is why. Like say you had it at a 500 RPM relay, 10-20% throttle and 50kpa on the MAP. You'd be at that while driving, so it's going to dip into PE.

Post your tune and logs and I bet it's something like this.

[lainez11]

ok I checked my log and I don't see anything obvious... but I am new to tuning!! but here is my log and tune if anyone wants to take a crack at it????? I know its probably something simple I'm just not seeing. but anyone's help would be nice.

[lainez11]

Ok... still can't figure it out.. thinking my base air flow is off would that cause a surge at part throttle right? Anyone have any ideas??

[WAcord]

fyi your tune says its a 5.7 not 6.0ci

[lainez11]

Yeah... would that cause my issue ?? Played with it some more today and noticed right when I hit 2000 rpm it surges... below it's fine... the PE is stock. Set to come in at 5500 rpms.. still can't figure out why its commanding it to 12.19 and surging ??? Do I have something set wrong. Could it be the DFCO???

[5FDP]

You have abuse mode still enabled.

Go to the engine TM tab and set the rpm to 8,000 and the mph to 0.


As far the cylinder volume is concerned, it needs to be set up for whatever size engine you have. So adjust the table for the 408 cubic inches and adjust the fueling as required.

[lainez11]

OMG!!!! 5FDP thank you!! ok so I did adjust the engine size to 6.0 and correct cylinder volume. I also did remove 10% on the VE table from 2000 rpm and up... noticed it was a big jump. BUT the Surge is gone!!!!! thank you u nailed it !! now I can drive it and start really fine tuning everything else!!! thanks everyone who replied problem solved I think it was definitely think it was the TQ management was set at 2000 rpms.