Not your average SES P0171, P0174 error code...

[adnoid]

For what it's worth, I (meaning my indie shop) replaced the big rubber boot and I got good results - for a bit. Then my mileage crept up again, the light came on, and I got the P0171/P0174.

Took it back, and they are now telling me that it's a leak through the "manifold tuning valve", which sounds to me like the Idle Control Valve. I let them keep it overnight to get it nice and cold and they used their smoker on it and found this item leaking, so they're replacing it and I'll report back on the results. I was about to get a MAF and replace it myself but I saw Greg's results...might still have to, but we'll see.

Thanks to all!

[adnoid]

It looks like it was the item labeled #7 in this post - the "Adjuster Unit". The local dealer had 5 in stock, told my guys they go out a lot. $306 for the part, but it looks pretty easy to replace yourself and I'm sure you could get the part cheaper.

http://www.xoutpost.com/x5-e53-forum/...tml#post565171

Just drove 30 miles back to the office, no problems so far. Going to have to relearn how to drive without the code reader plugged in.

[Weasel]

That (#7) in BMW terms is the "DISA flap" and controls the adjustable intake runner length system.

And for what it's worth, I almost never change MAF sensors at the dealer. Pretty much the only time I change them is when I read too rich at idle and the air flow reading is skewed from what it should be.

[adnoid]

Originally Posted by weasel56

That (#7) in BMW terms is the "DISA flap" and controls the adjustable intake runner length system.

And for what it's worth, I almost never change MAF sensors at the dealer. Pretty much the only time I change them is when I read too rich at idle and the air flow reading is skewed from what it should be.

I've got the one they took out and I'm going to look at it tomorrow. The flap had become disconnected completely, and what they tell me is that air was being drawn in through the control box and entering the intake manifold where the shaft should have been. I've got all the parts - never heard of this happening but I guess it's possible.

That's all they changed, put on 100 miles since then and no SES, I'll check the codes in the morning just to be sure.

[Whoopitupinmo]

How did your indie know it was the MTV?

I know you say they used a smoker. Is there a way to do this without taking it back to the dealer. Don't have a lot of equipment at our office/shop but would be interested to see if this is my problem, rather than valve gasket cover.

[adnoid]

Originally Posted by Whoopitupinmo

How did your indie know it was the MTV?

I know you say they used a smoker. Is there a way to do this without taking it back to the dealer. Don't have a lot of equipment at our office/shop but would be interested to see if this is my problem, rather than valve gasket cover.

They did use a smoker, and saw the smoke being drawn into the control unit. But I also heard a whistling noise when I started the engine, and it was really loud when first started and subsided as the car warmed. What I did is, when I noticed the noise, I opened the hood and took a picture with my phone of where it seemed to be coming from & emailed it to them to give them a place to start.

That said, this particular part looks very simple to remove - it's out in the open and uses an O ring seal, so if it's OK it should just go back in if you are careful removing it, worst case I guess would be a new O ring.

[Whoopitupinmo]

Thanks - probably not my issue then, do not hear any whistling or load noises under the hood. This is just baffling, performance seems a little hesitant at warm up, maybe first 2 minutes after I start the car, put in gear then go it does seems to hesitate for a minute or 2, then all is fine.

[1stE53]

Originally Posted by Weasel

That (#7) in BMW terms is the "DISA flap" and controls the adjustable intake runner length system.

And for what it's worth, I almost never change MAF sensors at the dealer. Pretty much the only time I change them is when I read too rich at idle and the air flow reading is skewed from what it should be.

Do you ever clean yours with a designed MAF cleaner spray? My DISA is busted to heck. Ordered one that will be here Tuesday. Just wondering if its worth cleaning the MAF or not.

[Puddlejumper]

I know I saw on here a DIY where somebody took it apart and caulked it.

[adnoid]

Just a follow up - 2 tanks of gas and a week of daily driving and no more codes. Gas mileage back to around 20, and drives great.