rukkee

iTrader: (3)

I've been watching my timing advance and noticed that it will go into the negative (-1.5 ,-2,0) when i let off the gas ....never when under load or at idle .... only when i let off . I'm pretty sure it's related to DFCO cause it seems to happen at the same time. I'm being parinoid but I'm asking just to see if this is normal or not . Thanks

Terminator2

It is normal for it to go slightly negative when you let off completely.

rukkee

iTrader: (3)

Thank you sir ..... That makes me feel much better . I'm using my superchips cortex as a gauge so I can watch 4 pid's at a time ...... but knock isn't one thats available. So i watch timing . I need to get something better soon. Thanks again!

RyRidesMotox

I'm assuming its on your 09 and not your 06? It might have something to do with the intake you have if the computer hasn't been tuned for it. The tuners on here can tell you everything you could ever want to know... There is a huge thread in the turbo general forum. Its all about how intakes mess with the MAF and trim levels and such. In any engine the air/fuel mix does weird stuff when you snap the throttle shut. The retarding of the timing is probably your engine compensating for knock under deceleration and a lien mixture. Does it do it if its in neutral or when the clutch is disengaged?

Damn so late haha

rukkee

iTrader: (3)

Yep ...it's my 09 . I'm pretty sure it's just fuel cutoff when engine braking or when its coming down in the rpm's from a rev. It wont do it in neutral . I'm still running the stock air box so no intake yet 8) thx for the reply.

CudaJoe

iTrader: (1)

can you see your STFTs?? what do they look like when you go from a 40% acceleration to a 20% acceleration?

or from a 40% to completely letting off?

rukkee

iTrader: (3)

Yeah I can look at the STFT's and get back to you . They must be half way decent cause my LTFT have been at 0 for the last week or so .... bouncing to a -0.8 at times.... so they have been great. I just bought a new stock filter from the chevy dealer .... damn thing was the same price as my K&N drop in. With the K&N i see as much as -8.0 LTFT but it's usually -5 most of the time.

My car feels stronger with the trims at 0 on the stock filter than it does at -5 with the K&N .

Terminator2

This belongs in the do not mod your stock intake or put an intake on your car without tuning for it thread.

rukkee

iTrader: (3)

It took me a while to come to my own conclusion about the K&N dropin . This site had me convinced it was the way to go . I'm glad i have a way to data log fuel trims ...That and many filter swaps later led me to 0'ed out LTFT's

I know I'm preaching to the choir talking to you guy's (Term and Cuda) ... this is for others

I would prolly still be running the K&N.... oblivious to what was going on if I didn't have a way to watch trims.....IMHO... Some way of data logging should be considered a must if your going to mess with the intake side of the turbo

Terminator2

Most believe that just because it does not trigger the MIL or it "feels just fine" it means there is no issue.