Lots of work done, still P0171, P0174, P0155

[Heckler]

I recently just replaced the following:

Valve cover gaskets
Valley pan gaskets
Upper timing cover gaskets
Vanos solenoid seals
Intake manifold gaskets
Both End caps on Intake Manifold, every gasket from the back to the air filter
OSV and all related hoses including the lower ones to the oil return pipe
Secondary air line o-rings
New spark plugs

Everything else was inspected and cleaned... Now what?

The only thing I can think it could be that has never been replaced are the 02 sensors, MAF, and fuel filter.

Any ideas? I already dumped a lot of coin into it, if I have to buy any more parts that dont fix the problem Im going to hook that Bitch up to my F350 and drag it around the desert!

[TwinTurboGTR]

Heckler, I feel your pain. Now lets see here. Left and right bank too lean... Star with the MAF. Take the assembly out and look inside. If there is a lot of junk, blow compressed air and clean it a bit. See if that works. Also (I had the p0171 code and this cleared it) There is a vac hose that connects to a solenoid. My hose was busted and threw the code. The hose attaches to a system under the plumbing of the air box (Between the air filter housing and throttle body assembly) and then runs on top of the intake and connects to that solenoid and then tee's off to the secondary air canister that sits to the left rear of the intake.

Also have you thought about the system running too rich? It could be running rich and the computer is fooled by throwing a code that it is running lean. Oxygen in the system could be fooling the computer to add more fuel to the system, trowing the balance off. How is the gas mileage? Sorry for just throwing things out there. But it is hard to tell. Hope the suggestions help.

Oh and after my valley pan fiasco, if the X decides it doesn't wanna start after a test run, I'll hook 'er up to my Duramax and whip er around the block a few times. You know, to know it whos boss.

[Heckler]

Yea I know the vacuum lines your talking about, there all good. I went through everything, I had it ALL removed off the motor and in the garage, inspected everything and cleaned everything. Since I was also doing the upper timing chain covers I had taken everything out, Including the secondary air line (the metal tube that makes it a PIA to get the water pump out... No if I ever have to replace the water pump again Im taking that pipe off instead of the balancer pully, it's only 2 bolts and a couple hoses.

[TwinTurboGTR]

Hmmmm.... Did you clean the connections with electronics cleaner? Are the injectors all firing? Umm another thing you can do is reverse the o2 sensors. I'm not sure it will work on a BMW but years ago I used to toy around with a Z32 TT. I had those codes, exact same ones. If you reverse the O2 sensors and and still get the same code, then it can be suspective that the O2 sensors are bad. Have you tried clearing the code first and seeing what happens? How does the X run? Does it run fine, like shit?

[Heckler]

Good Idea, Im going to try the swap O2 sensors and see if the code switches banks.

I cleaned everything, Im kinda like that I even blasted and powdercoated the valve covers.

It runs great! Smooth too...

Originally Posted by TwinTurboGTR

Hmmmm.... Did you clean the connections with electronics cleaner? Are the injectors all firing? Umm another thing you can do is reverse the o2 sensors. I'm not sure it will work on a BMW but years ago I used to toy around with a Z32 TT. I had those codes, exact same ones. If you reverse the O2 sensors and and still get the same code, then it can be suspective that the O2 sensors are bad. Have you tried clearing the code first and seeing what happens? How does the X run? Does it run fine, like shit?

[TwinTurboGTR]

Hmm runs smooth eh! Ahh f&^( it! put a sticker over th CEL and call it a job well done. haha.