P0171 and P0174 Errors (Bank 1 & 2 too lean)

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Mac The Tank
Joined: Fri 03 Jun, 2011 21:56
Posts: 127

  Z3 roadster 2.2i
Location: Brighton

P0171 and P0174 Errors (Bank 1 & 2 too lean)

Post by Mac The Tank »

Fired her up last night in preparation for this weekends' inaugural run of the year, only to notice it idling a "bit rough" and the dreaded orange engine light was lit. :( Got the code reader out and found errors P0171 (Bank 1 too lean) and P0172 (Bank 2 too lean). Going to check all the vacuum hoses tonight and I want to replace the fuel filter if I can (it sits on the driveway 6 months of the year).

How easy is it get to the fuel filter?
Are there any other common problems that affect the M54B22 (2.2l) in this way?

I found a good explanation of lean running codes here:
http://repairpal.com/OBD-II-Code-P0171-and-P0174
Mac
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Topaz Blue 2.2i Y2001 - only 16045 miles on the clock! (2011)
Update 04/14 - 18,702 miles
Del
Joined: Sat 19 Nov, 2011 18:35
Posts: 2136

  Z3 roadster 1.9

Re: P0171 and P0174 Errors (Bank 1 & 2 too lean)

Post by Del »

Going by 99% of the posts we see on this forum, this is likely to be caused by holes in your MAF rubber bellows (I think you have an upper and less visible lower?) MAF bellows on your car.

The fuel filter is under the car in the area of the nearside passenger seat (UK RHD). It is an aluminium canister about 10 inches long and about 3 inches in diameter. It is jointed to the metal fuel line by two 2 inch sections of fuel hose held in position with jubilee clips. The filter itself is clamped into position in its middle. Haynes recommends de-pressurising the system before removal i.e. remove appropriate fuel pump fuse, run engine until it cuts out and remove/replace fuel cap. You will still get a couple of cups of petrol leakage so have a suitable container to hand - but there will be no high pressure leaking. To be honest, they tend to go on for years and I would be surprised if this was your problem.
Mac The Tank
Joined: Fri 03 Jun, 2011 21:56
Posts: 127

  Z3 roadster 2.2i
Location: Brighton

Re: P0171 and P0174 Errors (Bank 1 & 2 too lean)

Post by Mac The Tank »

Ok thanks, will be having a look under the bonnet this evening so will report back later...
Mac
Image
Topaz Blue 2.2i Y2001 - only 16045 miles on the clock! (2011)
Update 04/14 - 18,702 miles
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akirk
Joined: Fri 20 Apr, 2012 08:11
Posts: 122

  Z3 roadster 3.0i

Re: P0171 and P0174 Errors (Bank 1 & 2 too lean)

Post by akirk »

looks familiar as does Del's solution...

I currently have gaffer tape on the hose which sits after the section with MAF plug in it until a new one comes...
now no engine light :D

Alasdair
Mac The Tank
Joined: Fri 03 Jun, 2011 21:56
Posts: 127

  Z3 roadster 2.2i
Location: Brighton

Re: P0171 and P0174 Errors (Bank 1 & 2 too lean)

Post by Mac The Tank »

Image

Found it :smug

Will try some tape to prove it off
Mac
Image
Topaz Blue 2.2i Y2001 - only 16045 miles on the clock! (2011)
Update 04/14 - 18,702 miles
Mac The Tank
Joined: Fri 03 Jun, 2011 21:56
Posts: 127

  Z3 roadster 2.2i
Location: Brighton

Re: P0171 and P0174 Errors (Bank 1 & 2 too lean)

Post by Mac The Tank »

Image

I will order parts 3 & 6
3= Rubber Boot #13541705209
6= Tube Elbow #13541435627
Mac
Image
Topaz Blue 2.2i Y2001 - only 16045 miles on the clock! (2011)
Update 04/14 - 18,702 miles
Mac The Tank
Joined: Fri 03 Jun, 2011 21:56
Posts: 127

  Z3 roadster 2.2i
Location: Brighton

Re: P0171 and P0174 Errors (Bank 1 & 2 too lean)

Post by Mac The Tank »

3= Rubber Boot #13541705209 = £13.61 inc
6= Tube Elbow #13541435627 = £11.30 inc

Chandlers BMW Brighton parts desk have them in stock, going to collect them both after lunch! 8-)
Mac
Image
Topaz Blue 2.2i Y2001 - only 16045 miles on the clock! (2011)
Update 04/14 - 18,702 miles
Mac The Tank
Joined: Fri 03 Jun, 2011 21:56
Posts: 127

  Z3 roadster 2.2i
Location: Brighton

Re: P0171 and P0174 Errors (Bank 1 & 2 too lean)

Post by Mac The Tank »

Parts fitted, took about an hour after struggling with the jubilee clips on the lower section that attaches to the throttle body :head:

All fitted, error codes cleared and so far so good! :drive
Mac
Image
Topaz Blue 2.2i Y2001 - only 16045 miles on the clock! (2011)
Update 04/14 - 18,702 miles
Del
Joined: Sat 19 Nov, 2011 18:35
Posts: 2136

  Z3 roadster 1.9

Re: P0171 and P0174 Errors (Bank 1 & 2 too lean)

Post by Del »

I'd be 99.999% certain that this was your problem - very satisfying and easy fix. :) I guess that vacuum pipe rubber must get brittle with continual warm air and heat from the engine and that bottom elbow must be constantly flexing.
Mac The Tank
Joined: Fri 03 Jun, 2011 21:56
Posts: 127

  Z3 roadster 2.2i
Location: Brighton

Re: P0171 and P0174 Errors (Bank 1 & 2 too lean)

Post by Mac The Tank »

Yeah, I replaced the upper section too at it was badly cracked all over too.

Time + heat doesn't do the rubber any good it seems.
Mac
Image
Topaz Blue 2.2i Y2001 - only 16045 miles on the clock! (2011)
Update 04/14 - 18,702 miles
Brian4
Joined: Mon 19 Dec, 2011 19:02
Posts: 541

  Z3 roadster 3.0i
Location: Hinckley

Re: P0171 and P0174 Errors (Bank 1 & 2 too lean)

Post by Brian4 »

Mac The Tank wrote:Parts fitted, took about an hour after struggling with the jubilee clips on the lower section that attaches to the throttle body :head:

All fitted, error codes cleared and so far so good! :drive

Real pain in the neck to fit. Much easier with the engine out of the car at the factory :) :)
Brian
3.0I Topaz Blue


2000 E36/7 Z3 3.0i
2016 F31 335d
2015 F21 118i
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