*Hurray for first post! Always lurking, never reg'd till now. Also, for what its worth, im in my 30's and have built everything from lowrider trucks to FC (rx7) turbo-IIs so ive been around the block*

Anyways, posting for a friend.

He has a 07 SS/SC with Stage-2 and GMPP cat-back.

Everything was running fine.

Now, weve added a CAI. The throttle body is clean. The MAF is functioning properly, facing the right way, and seated squarely in the CAI.

However, the car is leaning out in 2nd and 3rd gear around 4000rpms and wont go past 5500rpms at all.

Right through first gear, everything is fine. When not making boost, the car is fine too. Its only at wide open throttle that it leans/bogs.

From my experience with FI cars, im thinking that because the car is tuned for the stock intake and now that we are adding more air with the CAI, that the ecu can not compensate for the increased airflow because the mapping is 'locked' from when the car was tuned prior to the install.

We both work for a dealer so have free (hurray) access to our tech buddies, tech-2's, etc., so im thinking that on tomorrow (Monday), simply re-doing the stage 2 calibration with now having a CAI should fix the problem.

Ive told him that in my experience, the stock tune allows the computer to compensate for running to rich or too lean and return it back to stoich. The Stage-2 tune is, well, tuned, for more hp and 'ties the hands' of the ecu.

All thoughts are welcomed but please, dont turn this into another ZZP vs Injen vs KN vs Ebay CAI thread like most of these threads turn into.

Thanks guys!

 

Hmm strange, I litterally installed my intake right after I parked it from getting back from the dealership for GMstage 2 and my GM tune is still super rich haha

 

^yeah, it does seem strange. Him and I have both been reading thread after thread for the last 24hrs and cant seem to find the answer. I mean, we find the usual "its cause you have brand-x CAI instead of brand-y cai!' responses, but, ultimatly it seems that the LSJ is very hit or miss as to weither the car will accept a CAI and not throw a tune.

FWIW, when we first started up the car, it had no code, rough idle, and ran very rich (lots of black smoke). Once the idle settled down, it started to run normal, ecept for what i said in my OP.

Also, is it possible that for some weird reason, the tune hadnt been performed when the S2 was done?

 

You never know with these damn dealerships haha, I made sure mine was installed by a forum member who happened to work at a chevy dealership near me, I'd say check if you can rev it to 7k like you should be able to with the tune, but if your having issues revving it up that high, wouldn't help haha

 

how do you know its lean

 

^^I dont know for certain, but it definatly sounds like its not getting enough fuel a WOT. It sounds like when your auto-xing and cornere hard with only a little fuel (or, right before your car runs out of gas, lol)

@Phyrric, i know exactly what your saying, lol! The techs I use at work are aslo friends outside of work so ive got a lot of faith in them, but, just to be certain, we uninstalled and reinstalled the intake ourselves too just to be sure. Also, we can redline it in neutral and 1st gear, but, not the higher gears.

It really seems these cars dont like CAIs do they (according to the 17326827453879145389754834275984 threads about intakes, lol)

 

Does it go to 7k? and its more the TC that doesn't like intakes

 

I cant go to 7k in any gear other than 1st

 

you would know if the stage 2 tune wasnt installed. the larger injectors in the s2 kit on the stock flash would run super rich (black smoke), 6500rpm rev limit, and id expect codes for exhaust rich bank 1.

what intake did you put on? some intakes cause the air to be metered incorrectly and the only real fix is a tune. also, is it a dryflow or an oiled filter? if its an oiled filter it may be over oiled and fouled the mass airflow sensor. if it is an oiled filter, get a can off maf cleaner and clean it, clean the filter and apply less oil.

the factory flash should be able to compensate for an intake, it really doesnt add that much more air. the first thing id do is disconnect the battery to reset the fuel trims and try again. check over all your clamps, double and tripple check your maf. check the breather hose too, anything leaking unmetered air into the intake will cause lean running issues. if all else fails, throw the stock airbox in and see if it fixes the problem, if not you may have something else going on.

 

Thanks Sharkey.

We are going to try and reset the ecu by disconecting the battery, cycle the ignition a couple of times, reconnect, and let idle for 5 minutes. We had the battery disconnected when we installed the intake the first time.

If that doesnt work, i think we are gonna try the airbox mod. Along the way, gonna see if there is anything we missed on the CAI install. IF all look well, then modded airbox it is.

My friend is happy with the hp hes making now....just really want to hear that whine!

 

shouldnt be going to wot if your lean

 

With gm tune you shouldn't never be running lean. They make the gm canned tunes rich as a ****.

 

What are you using to measure your AFR? What AFR are you seeing during the lean condition? Are there any other variables other than the addition of the CAI? Are there any DTC codes being thrown?

Based on the fact that this problem presented after the installation of the CAI I will hazard a guess that your MAF is not reading correctly, especially since this is only a problem when you are in open loop.

 

Well he don't have an wideband so he's guessing he's lean and he said no codes. Read

 

Sounds like we need more info then. Doing anything that changes the operating parameters of the engine without an adequate method of monitoring the key variables is unwise at best. Get a log of the car and actually figure out what is going on.

 

Well, obviously im not driving at WOT.
We did the CAI and went to go test it. We noticed the 'bogging' at WOT and went back.
We re and re'd the intake including resetting the ecu and went and test drove it again to the same results.

 

Tool-wise, nothing.

Im seeing the engine struggling. Its being restricted to 5500rpm max in any gear other than first. Its bogging like its not getting enough fuel

All we added was the CAI. We already had STG-2 and GMPP cat-back prior to install

There wasnt, but not there is. Ill be alble to scan the code at work tomorrow with a tech-2

We are going to put the oem piping back in to ensure that the maf wasnt damaged to atleast remove that variable.

 

And we may actually pop over to Parts Source (like AutoZone) and get the code read today (my buddy is too impatient for tomorrow, lol)

 

Ok, problem solved!

The cone filter itself was jammed on the end of the CAI pipe so tight/far (so it wouldnt rub on the splash shield) that the pipe itself was almost 'bottoming out' on the top of the cone filter.

At WOT, the engine must have been having a hell of a time drawing in air (like trying to breathe from the bottom of a pool through a pipe).

So, we trimmed back the pipe an inch and a bit so it didnt go as far into the cone and everything works fine now...it screams...doesnt bog...and no code!

Thanks all for the help!

Now, what should the next mod be....heat exchanger? Downpipe?

 

midlength stainless header and downpipe. follow that up with a heat exchanger and dual pass end plate.

 

Interesting issue. Glad you got it sorted. As for next mod's.... how about trans mounts? If you are still stock I'd highly recommend getting rotated mounts.

 

Like a zzp one? I can drive there and get that

 

Cobalt & Ion ---> ZZ Performance