P0174 Lean Bank 2 Code (forever...........)

[jfl330]

I have replaced everything, plugs, wires, O2 sensors, coil packs, etc. Sent out injectors to be professional cleaned and tested.

Pulled intake and replaced all gaskets.

When it is cool outside, it seems to run fine. When it is warmer out, (perhaps >80F), the problem starts. Usually I feel it first as a stumble at idle, then a hesitation on accelerating, then really rough (cam like) conditions. Once it starts, B2S1 stays at 0.1V or less more and more often, until it never goes over 0.1V except when decelerating.

Anyone have a suggestion (other than C4) that I can try to resolve this?

ONLY Bank 2, bank 1 O2 always switches properly.

Not that it matters, but stock except for BBK TB and intake, lid, and cat back.

Jon

[FinZ28]

Do you by chance also have a P0300 code, too?

How much larger in diameter is the BBK TB over stock?

Did this code pop up after a particular mod?

When is the last time you cleaned your MAF?

[pajeff02]

Swap your O2 sensors from side to side, clear your codes and see if the problem stays on Bank 2 or moves to Bank 1.

[jfl330]

Do you by chance also have a P0300 code, too?

How much larger in diameter is the BBK TB over stock?

Did this code pop up after a particular mod?

When is the last time you cleaned your MAF?

Sometimes get P0300, did yesterday without the P0174. MAF is clean, 80mm BBK TB, why would this affect only bank 2?

Thanks!

Jon

[jfl330]

Swap your O2 sensors from side to side, clear your codes and see if the problem stays on Bank 2 or moves to Bank 1.

Problem NEVER leaves bank 2, no matter what. Switched O2's side to side, switched injectors side to side, replaced the four coil packs on bank 2, replaced all plugs and wires. Problem stays bank 2.

Jon

[SMWS6TA]

Have you followed the wire harness for that bank?


Stumble at idle, then a hesitation on accelerating are also signs of vacuum leaks and dirty MAF. Check/clean these too.



I just saw you stated your stock except for BBK intake & TB. They have been know to have vacuum leaks and fitment issues. Have you had a tune since the intake/tb install?


Bigger intake/TB moves more air which is good for the engine however if the fuel trim tables are not adjusted you will get a lean condition and that can also cause some of the issues you're experiencing.

[jfl330]

Have you followed the wire harness for that bank?


Stumble at idle, then a hesitation on accelerating are also signs of vacuum leaks and dirty MAF. Check/clean these too.



I just saw you stated your stock except for BBK intake & TB. They have been know to have vacuum leaks and fitment issues. Have you had a tune since the intake/tb install?


Bigger intake/TB moves more air which is good for the engine however if the fuel trim tables are not adjusted you will get a lean condition and that can also cause some of the issues you're experiencing.

I tested the leads from the O2 sensor socket back to the pcm connector and they are good. Why would a MAF cause an issue on only one bank?
B2S1 O2 sensor will stay under 0.1V constantly. Yet other times, it switches normaly and the car runs fine.

I could see the tune being an issue if both banks were lean, but the driver side is fine.

I guess I can go back through and check for vacuum leaks again.

Jon

[5150]

Just a guess a big one at that but it could be your PCM. I had to replace mine awhile back. My tranny was kicking in and out of lockup. It progressively got worse. Haven't had a problem since.

[jfl330]

Just a guess a big one at that but it could be your PCM. I had to replace mine awhile back. My tranny was kicking in and out of lockup. It progressively got worse. Haven't had a problem since.

Replaced PCM, same problem, put original back in.

Jon

[FinZ28]

I'm leaning towards a vacuum leak. I had one awhile back and it was most noticeable when I first started the car. In my case it was a hole in the PCV hose elbow, just before the hose goes into the intake on the passenger side behind the throttle body. Also caused a lean condition, but in both the left and right banks.

[SMWS6TA]

Just thought of one more possible cause. Check your exhaust manifold on the Passenger side (I believe that's Bank 2). An exhaust leak on that side could cause it.


Also do you still have CATS? That to is also another possibility.

[0rion]

like he said....make sure you don't have an exhaust leak on that side pre-O2 and it seems like I've read those BBK intakes fit like shit. You've checked it really well to make sure there's no vacuum leak on that side? If you don't have any exhaust leaks (first thing I would check) then I would start throwing stock parts back on it to see when it does away. How's the car idle rpm wise?

[jfl330]

like he said....make sure you don't have an exhaust leak on that side pre-O2 and it seems like I've read those BBK intakes fit like shit. You've checked it really well to make sure there's no vacuum leak on that side? If you don't have any exhaust leaks (first thing I would check) then I would start throwing stock parts back on it to see when it does away. How's the car idle rpm wise?

The intake was on the car when I bought it. I pulled it to check for leaks. It was all snotted up with RTV when I removed it. I thought that was wrong and bought new rubber "oring" style gaskets and put it back together. Perhaps based on what you said I need to pull it again and RTV the crap out of it (kind of like I found it).

I doubt it is an exhaust leak as I doubt the stock exhaust manifolds have ever been off.

When it runs good, it runs great. When its warm to hot out, the problem starts. Stumble at idle, miss on acceleration, etc.

Jon

[SMWS6TA]

Was it completely rtv or just one side?

[jfl330]

Was it completely rtv or just one side?

Both sides, it was a mess, but perhaps it did not leak becuse of it. I can do it a lot neater but get the job done.

Jon

[cammed goat]

Even with the manifolds never being off the car, you could still develop a leak if a bolt is loose, broken, or you could possibly have a crack in the manifold.

[jfl330]

Even with the manifolds never being off the car, you could still develop a leak if a bolt is loose, broken, or you could possibly have a crack in the manifold.

At this point, I have to check everything so this goes on the list. I don't see how the problem would be intermittant with a exhaust manifold leak.

Jon

[SMWS6TA]

small crack in the manifold as it heats up, metal expands.

- - - Updated - - -

small crack in the manifold as it heats up, metal expands.

[pajeff02]

^^ This.

[jfl330]

^^ This.

What is best way to inspect for manifold leak? Remove it?

Jon