Cobalt help

[BeermanSS/SC]

Hey guys, I've been slowly working on this. Still learning as I go along. I just did some logging today and I seem to have a ton of knock still. I've made some changes in fueling and timing but I don't seem to be able to get rid of it. Hope somebody can give me some suggestions. Also, while cruising my afr is probably averaging 14.3 or lower. I have an LC-1, it was just calibrated so everything is good there. Why will the car not hit its commanded afr (14.7) at cruise?

Thanks in advance for any help you guys can give me.

BTW mods are GM stage 2, injen intake, vibrant header/dp, gmpp sport exhaust, and lc-1 wideband. Just basic bolt-ons.

[08BlackSS/TC]

Having the same problems with my buddy's 07 SS/SC. any info would be helpful

[air1kdf]

It sounds like you need to calibrate your MAF. It probably thinks you have more air than it really is injesting.

[black06g85]

I can't read your tune at work unfortunately, but I'll see if I can remember to drop in and check it out tonight.

[BeermanSS/SC]

I don't know how to calibrate a maf. Is it easy or should have someone do it?

[BeermanSS/SC]

oh yeah black if you could check it out when you get some time that would be great. I'm just kinda frustrated right now. Cannot seem to get rid of the knock or get the afr's right.

[black06g85]

here give this a quick try.
some basic fixes, but you will need to retune the mad via afr error %.

[BeermanSS/SC]

I downloaded the tune, I'll upload it to the car and try to get some logs tommorrow. I'll post some results in a day or two.

Thank you for the help, Looking at the tune file, I might have a few q's for you later.

[black06g85]

no prob man, i'll keep an eye on this thread

[BeermanSS/SC]

Heres the results, The fueling seems to be better, less knock except during normal acceleration, seems to still knock some there. Idle seems to surge more than before. I have to review the idle changes and maybe change those back. But it seems to be quite a bit better than before.

[black06g85]

good to hear, I'll check this log when I get home.
Do you still have the stock mounts in your car? If so that could be causing some of the KR spikes. Yeah if you want put back your idle tables to clean that up. These cars are weird like that. Some surge some don't on the same setup.

[BeermanSS/SC]

Yeah all the mounts are stock. Thinking I should replace? I was looking at some the other day. TTR upper mount and the Prothane Tranny mounts. Could it be false knock from the drivetrain moving?

[black06g85]

I've seen it a lot mostly at throttle tip in and gear changes. I had a lot of KR on my car, switched to solid mounts, and gone

[Ryze]

^^ hmm, same here stock mounts and I see about 5-6 degrees of knock retard between shifts, and throttle tip in.. I thought that it was my PE enrichment rate, but now that you say solid mounts possibly that's my issue

[black06g85]

try a nice set of Poly ones. Not as horrible vibrations and it gets rid of 85% of the wheel hop.