Lean codes keep coming back - need help

[stephenkirsh]

So I've had lean codes for a while, 0171 and 0174. Extra symptoms:

- Rough idle when starting the car for the very first time in the day.
- SES lights only come on within the first few miles of driving, aka, when the engine has yet to fully warm up


Work I've done:
- ccv
- spark plugs
- valve cover gasket
- lower and upper intake boots
- replaced vacuum plugs
- swapped MAF from my dad's 330 and rough idle was still there
- VANOS return line

Haven't smoke tested it yet, but here's my fear. Since the problem only happens when the engine is cold, driving it somewhere will warm it up and seal the leak.

Any ideas at this point? I'm running out of ways to fix this.

[danewilson77]

Throttle body gasket, or disa gasket leak? Intake gasket?

You're looking for un-metered Air flow, and it looks like you've taken care of a majority of them.

Continue throwing darts or complete a smoke test.

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[stephenkirsh]

Throttle body was recently inspected (last week) and it all looked good.

DISA gasket is very possible.

What's the intake gasket?

[kayger12]

Check the vacuum lines from the secondary air pump.

If you're good there move on to the DISA gasket.

[stephenkirsh]

Isn't the secondary air pump exhaust related?

[kayger12]

Isn't the secondary air pump exhaust related?

It is. It feeds air to the cats during cold starts, but iirc it is connected to the intake manifold via vacuum hose as the pump is actuated via a vacuum powered check valve.

If you're only getting the condition during the first cold start of the day it points me to the SAP as it only operates during cold starts (not subsequent starts on an engine that has some leftover heat in it from being run earlier).

There's also a code for the SAP being bad, but I think that involves a bad check valve or the pump not working. Not sure on that.

[danewilson77]

What's the intake gasket?

The gasket for the plenums.

http://i1015.photobucket.com/albums/af278/nicee46/2_5lintake2-vi.jpg (http://s1015.photobucket.com/user/nicee46/media/2_5lintake2-vi.jpg.html)

[stephenkirsh]

Ugh that looks nasty.

Looks like there's a million more options still. I guess I just need to do a smoke test.

[danewilson77]

Yes. Looks like you've fixed most culprits. Could maybe replace disa o-ring and look at SAP as KG mentioned. Both are cheap. Beyond that though, smoke is your friend.

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[kayger12]

In case you need it.
http://img.tapatalk.com/d/14/01/21/e2y4a8y8.jpg

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[stephenkirsh]

The entire DISA valve would be on my list. My dad's is starting to make noise and it's not even at 50,000 miles yet. May as well do it I guess. Hopefully that's the issue?

[BCS_ZHP]

When you changed the upper & lower intake boots, did you replace the "F" connector and that tiny diameter vacuum line? It's easy to crack that "F" connector & not know it, and reusing that 3" of tiny vacuum line is also a possible leak point.

[danewilson77]

When you changed the upper & lower intake boots, did you replace the "F" connector and that tiny diameter vacuum line? It's easy to crack that "F" connector & not know it, and reusing that 3" of tiny vacuum line is also a possible leak point.

Good point. It's also easy to not properly seat the lower boot joint on the TB (the part with the tongue and groove)

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[stephenkirsh]

Got a smoke test done last week. DISA valve was leaking a lot. Time to do that.

Good point on the stupid F connector.

Any tips for putting the long piece of vacuum tube into the short 3" piece that connects to the F connector?

[danewilson77]

I apply a small amount of Silicone and then push like hell.

[derbo]

I hope I wont be in a situation like you..I am getting lean codes too.. I did recently rebuild my DISA but I used the new blue gasket from GAS.

[Cadeez]

My check engine light came on recently so I had the codes ran, got the same two (P0171 & P0174), looks like I've got a looong list of stuff to work though...awesome. The local BMW dealership (Kuni) asked if I had ran out of gas recently, and that these two codes were from low fuel in the tank... Now, I'm no genius or BMW mechanic, but you're telling me that the check engine light comes on in a ~$35k BMW (when new) when it gets low on gas?? C'mon man...

Question: Would the results of whatever is wrong cause a sort of "dead spot" at take off? When I'm pulling away from a stop, I hit the gas but nothing really happens for a second, then I'll press a little harder and it takes off. I just got the car so it's made getting used to the clutch a bit trying. Your body's natural reaction at take off is to lean just slightly forward, anticipating the push back in your seat, but I find myself almost hitting the wheel sometimes because I'm expecting the car to move but it's not! There's a definite delay in the throttle response. There was reference to this phenomenom in a thread I read on Bimmerforums or E46Fans recently, which is why I ask. Stated issue was bad MAF or intake boots, etc, basically everything mentioned on this thread

Also, my gas mileage isn't super great, I'm assuming air leaks in the intake system have can an adverse effect on your mileage as well?

[stephenkirsh]

Sounds like a dying fuel pump to me. A bad fuel pump can cause those two error codes, as a bad pump can starve the engine of fuel.

I've never experienced a bad pump, but read these similar symptoms all the time. A pump is like $300 and they're fairly easy to replace.

[Cadeez]

Hmm I suppose that could be it as well, but hopefully it's not the pump. Although I looked on ECS's site and you can get one from $100-$280, so that's not too bad. I did the pump on one of my cars, can't remember which one, but if I remember correctly it's on the passeger side right under the rear seat cushion. Pretty plug and play, the install was a piece of cake. I plan to replace the filter here soon, just because I always do when I get a new car, we'll see if that helps any. Thanks for the tip!

[stephenkirsh]

Just to update and hopefully not jynx anything, I've been code-free since installing the new DISA valve a month ago.

It hasn't been as cold as it was in dec/jan, though.

My rough idle is gone, too.

[ELCID86]

Good to hear. Hope it stays gone.

[mbeckel]

I keep getting 2882 and 2883 codes on mine. So far I've changed vacuum hose and fuel filter and added the CAI. Still getting these codes. Any suggestions on how to fix this?

Sent from in the bushes

[LivesNearCostco]

mbeckel: What do those codes mean?
StephenKirsch: Sounds like you fixed it!

I had two lean codes in the last 6 weeks, so 2 weeks ago I cleaned the MAF and cleared the code. Last night while doing CCV, I saw the F-connector was unplugged from the throttle body boot! And my CCV--with related hoses--seemed to be in alright shape. Anyway, I feel dumb about the F-connector... trying to remember when I last unplugged it. According to my maint. log, the last time I specifically know I unplugged it was November when I did my starter. Unless I unplugged it when I cleaned the MAF?

[mbeckel]

Mixture bank malfunction

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