2006 LSJ Cobalt Idle Issue

[06_sic_ss]

Wanted to get a little brainstorming going.

Been having an issue with idle for the past 2 months since I got the motor back together with the new Blower.

The issue only arises after the car comes up to temp. I have gotten it to the point where cold start is solid and will fire right up.. and idle smoothly until 170 or so degrees. This is when issues arise and the car dies.

If you are driving the car after it warms up and you come to a stop light you have to blip the throttle a couple hundred rpms to keep it alive. The Rpms arent surging or anything, it will just randomly die out of no where if u let it sit on its own. I have a couple logs I can attach if it will help.

A quick mod list is

Duel Walbro 255's ( 1 in tank, 1 boost referenced in line )

ZZP Stage 2 camshafts. ZZP S2 is 216/218 @ 1mm and 10.78mm/10.69mm lift, 111 LSA

Lysholm 1600AX blower with 3.2 Ring.

Port and Polished M2 Cylinder Head, Supertech valvetrain ( stock diameter valves) 78 LB springs

A few things i have noticed is that the car seems to command so much fuel suddenly that it dies and when it does this the timing shoots up.

Timing at idle is around -3.5* and when it dies it shoots up to 25.

[laser_racer]

Got log and tune? You check for boost leaks?

[06_sic_ss]

got both yep. i will upload them.

and no leaks from what i can tell.. been looked over multiple times

[06_sic_ss]

heres the tune and log

[06_sic_ss]

what makes me lean away from a boost leak is how it only does it after warming up and never throws a code

[06_sic_ss]

heres another while idling on the dyno

[06_sic_ss]

heres 2 more while idling on the dyno

[laser_racer]

Did you start this tune your self? You have a huge problem with your maf its got this huge belly in it. What injectors are you running?

[HNRClothing]

Yah MAF should have a some what smooth curve upward.

I am guessing you have a LS4 throttle body? Thats my guess what part of your problem is.

[06_sic_ss]

i do have an LS4 throttle body and i have pretty much taken over the tuning on it because of the poor results i got from a local shop.

explain the belly to me. this is the first i have heard of that.

[06_sic_ss]

and i am running 80lb siemens injectors

[06_sic_ss]

ive considered switching back to the stock throttle body

[laser_racer]

Here give this try and see what it does.

[06_sic_ss]

thanks man. ill do that

[06_sic_ss]

ill post back up results. ( going to piss off neighbors )

[06_sic_ss]

says cant open the file for some reason.. says index was outside the bounds of the array?

[06_sic_ss]

what all did u change within it. or u can email me the file if thats the issue..

[laser_racer]

You got beta addition?

[06_sic_ss]

suite 2.22

assuming i should update asap.

[HNRClothing]

You need beta...

He definately changed the maf curve. Compare the one you had and his, it is supposed to look like that.

Other things I noticed was some injector values..