BlackFya

Fellas my brother took my car in for a NC inspection and the service station told him it was throwing two codes and it was lean on both banks, making the check engine light come on. My car sits 95% of the time because I am overseas with the AF. What could be the possible cause? Any help would be greatly appreciated!

AORoads

IDK, but here's a bump===someone will pick it up as a topic.

KOZ

Lean both sides is usually an air leak.... un-metered air is making it into the engine.

Vacuum leak, or intake leak. Any mods? The LS engines have been known to suck the intake gaskets in. I have a 6ltr with this exact issue...

BlackFya

Come to think of it, this started shortly after I had a VMax ported ls3 intake manifold installed. The shop reused my gaskets. This could be the culprit. I was unaware of the engines sucking in the gaskets. Other than that, the only other under hood mod is a haltech kb and lg headers.

PDsVettes

Which gaskets? TB? Head?

v26278

Its either an air or vaccum leak or a fuel issue. If its both banks, then any fuel issue is likely related to pressure from the pump, and any air or vacuum issue is likely at or ahead of the entry to the intake manifold. First thing to check is the recent intake installation and make sure its all snug with no leaks. It could also be that your tune or ECM calibration is not correct given the extra air-flow from the ported intake. Is a re-tune generally needed with that installations and did you re-tune?

NoRuls

Really, they used the same intake gaskets???? Saved $50 +-,,, there's a good idea! Time for a new shop!

dpigguy

MAF issue will throw lean codes as well. Check to ensure it is correctly installed (ie; not upside down, loose, etc) then your tune. My '08 had both codes for several months. BG engineers finally chased it to air leaks causing turbulent flow across the MAF. Sealed leaks using metal AC tape and codes haven't returned for 7 years!! Stock air intake and no mods on the car.

KOZ

The individual intake gaskets between the intake manifold and the heads

slayer6x6

A little trick a mechanic would use is to spray around the intake and throttle body with 2+2 or brake cleaner and listen for a jump in idle. That would indicate an a vacuum leak. If it's a small leak it might not change the idle so you'd have to have a scanner that would read live data, or an air fuel gauge and watch that to go rich while you're spraying the gasket areas.

slayer6x6

PS that stuff is highly flammable so be careful.

Also, I've seen some cars only leak when cold or warm. Sometimes the temperature change is enough to open or seal a small leak. That's unlikely, but stranger things have happened.

Vegas1500

I used to use gasoline in a small bottle.

slayer6x6

Sheesh, I didn't realize OSHA was monitoring the forums.

Most of us are backyard mechanics looking for backyard fixes. The safest way to check for leaks is to get a smoke machine and smoke the intake system, but a can of brake clean is a tad bit cheaper.

djbrun

1. Check for a vacuum leak, fix the leak if found.
2. Clean your maf. The KB design can cause turbulence across the maf. Changing the intake may have been enough change to cause the issue.

If no vacuum leaks are found, and you cleaned the maf, and the lean codes come back. Change the KB to a MF air intake with the maf forward design.

FYI, my car could not run the KB at all, my fuel trims were all over the place throwing lean codes. The MF103 cured that.

Good Luck,

DJ

BlackFya

Thanks for the insight fellas. My brother took it back to the shop and they did the smoke test. It was the intake gaskets. A new set was installed and seems to have fixed the issue. A street tune was done also and all the codes cleared. I will take extra precautions like cleaning the MAF when I get back stateside. Thanks again!

djbrun

Good, glad to hear you got it fixed.

DJ

Landru

Sweet success!
When I'd read shop reused the gaskets my first thought was there's the likely issue. But everything's good, shop found the issue & stood behind their work.

As for the MAF, if it isn't malfunctioning I'd leave sleeping dogs lie.
Yea, gutless I am.

KOZ

Intake gaskets strike again!

Good deal glad you got it sorted out.

MTsVette

BlackFya,

Glad you got your ride squared away.

Thanks for your service.

SMSgt (Ret), USAF

MT

BlackFya

Thank you SMSgt for serving before me! Paving the way, huuaaah!