[Shadow21]

I just replaced my intake with a injen cold air system on my 2008 gs and I'm wondering if I should offset the extra air with bigger injectors since it seem to every once in a while want to bog down at a low idle the start accelerating but very rarely. Also have maf to much air codes. P.s. also plan on having the car tuned at some point.
Also any other good proformance mods would be appreciated.

 

[chase206]

No. You cannot swap bigger injectors without a tune. If you're N/A you don't need bigger injectors on the 2.0 until you're breaching about 180WHP then you'll need larger injectors. Remember, MORE FUEL isn't MORE POWER. More air is more power if you can feed enough fuel to keep up within a 12.5:1 AFR at WOT.

Your 2008 ECM is too finicky for a cold air intake. Try swapping for a 2004 ECM out of the junkyard and see if that helps.

 

[Shadow21]

Will the ecm work as a direct swap or will it need to be modified

 

[chase206]

The ECM will be a direct swap as long as it's a SIMK43 ECM from about (mid)2003-2004 and from a MAF based CVVT car. The MAP based non-CVVT 2002-(early)2003 cars will not be compatible at all. The 2005-2006 ECMs will work as well but they also can be finicky to an extent. Not as bad as the 2007-2008 ECMs. Make sure the transmission type is the same on the donor car or you will have issues.

 

[Nai150]

The ECM will be a direct swap as long as it's a SIMK43 ECM from about (mid)2003-2004 and from a MAF based CVVT car. The MAP based non-CVVT 2002-(early)2003 cars will not be compatible at all. The 2005-2006 ECMs will work as well but they also can be finicky to an extent. Not as bad as the 2007-2008 ECMs. Make sure the transmission type is the same on the donor car or you will have issues.

wait so I have a 2007 SE, you're saying I have to ECU swap or get a tune if I wanna put the Injen cold air on my car?

 

[chase206]

wait so I have a 2007 SE, you're saying I have to ECU swap or get a tune if I wanna put the Injen cold air on my car?

It's hit or miss. Could be a number of factors for this guys car such as non-OEM MAF or another critical sensor in air/fuel loop causing a lean condition. Injen is supposed to work on 07-08 and if it doesn't, an ECM swap is a cheap alternative to an actual tune. $30 at the wrecking yard and you have yourself a used ECM. Lol.

 

[Shadow21]

This is what I found. It's a simk43 but these hookups are different from what I have

 

[chase206]

The sockets should be the same unless you bought the wrong transmission type. The dual sockets are from an automatic car while the single socket is from a manual car. Do you have a manual car by chance?

 

[peachferrari]

Are the 08's much more sensitive than the 07s? Because I have cold air on my 07 GT and have never had any lean codes (though I did have O2 codes with headers). That said, when I had my 05 I did get lean codes and I had to reset the ECU a few times to get it to relearn the fuel mix. I'd start there before you go swapping other parts.

 

[Shadow21]

No mines a automatic trans

 

[peachferrari]

View attachment 137263
This is what I found. It's a simk43 but these hookups are different from what I have

Is that even an ECU? Looks different somehow....

 

[chase206]

Well if that socket and plugs don't match up you must not have a GS 2.0... You must have a GT or SE 2.7L with the 5 plugs. In your first post you said you had a GS... If that's the case you want a 2.7L ECM with 5WY17 or 5WY18 on the label just below the Siemens logo. Or Z4, Z8, ZC, JS, JN on the socket label.

@peachferrari the 07/08 ECMs are nearly identical in the way they can trip a lean code from a CAI. Injen is really the only one that works consistently because of the slightly smaller diameter leading into the MAF speeding up air velocity and tricking the ECM into providing a little more fuel.

 

[peachferrari]

@peachferrari the 07/08 ECMs are nearly identical in the way they can trip a lean code from a CAI. Injen is really the only one that works consistently because of the slightly smaller diameter leading into the MAF speeding up air velocity and tricking the ECM into providing a little more fuel.

Interesting that mine has never thrown a lean code. I just have a no-name Ebay CAI on it with a good AEM filter. When I bought the car it had a "hot air" intake with just an elbow off the throttle body and the filter sitting behind the battery. That didn't trip a code either. On my 05 I had an Injen SRI (filter right behind the headlight) and it initially tripped codes for both banks lean, but after resetting the ECU a couple of times it went away and never came back.

 

[chase206]

Interesting that mine has never thrown a lean code. I just have a no-name Ebay CAI on it with a good AEM filter. When I bought the car it had a "hot air" intake with just an elbow off the throttle body and the filter sitting behind the battery. That didn't trip a code either. On my 05 I had an Injen SRI (filter right behind the headlight) and it initially tripped codes for both banks lean, but after resetting the ECU a couple of times it went away and never came back.

You might have gotten lucky. I've run a large variety of ECMs from 2003 to 2008 on my car with an AEM pipe with AEM filter as well as the eBay kit with a Spectre filter. I ended up with a lean condition on anything from 05-08 unless it was a modified ECM such as a Fiebruz 2006 ECM. I don't know specifically what causes the newer ECMs to do that, but it has something to do with the added AFR algorithms. Those additional algorithms can be disabled as I've seen on the Fiebruz tune, however.