# System too lean Bank 1 / 2



## Sharbotcreek (Aug 25, 2013)

So to rehash the situation, I have a 2004 V8 Phaeton with 160000kms on it. I bought it 6 Months ago with the MIL on showing code for system too lean bank 1 and 2. I have tried a few things to get rid of that code but it keeps returning, and emissions time is approaching and I need to fix it permanently and would really appreciate any and all input. Here is what I have tried so far.

Swapped out both MAFs 
New fuel filter
Fuel pressure tested within spec several times
replaced 3 coil packs 
Full gates timing belt kit installed
Only minimum 91 fuel
New spark plugs
replaced the broken short arms on intake
Propane test reveals no leaking EGR
New air filters and cleaned snow screens

When I clear the codes, the MIL stays off for aprox 200kms then its back on. Oh and it runs rough for the first few minutes of clearing the codes. I have attached the most recent scan below.

Monday,19,May,2014,15:34:43:35803
VCDS -- Windows Based VAG/VAS Emulator
VCDS Version: 12.12.2.0 (x64)
Data version: 20140212


VIN: WVWAF63DX48011311 License Plate: 05/19/14
Mileage: 161360km-100264mi Repair Order: 



--------------------------------------------------------------------------------
--------------------------------------------------------------------------------


Chassis Type: 3D (3D - VW Phaeton (2002 > 2006))
Scan: 01 02 03 05 06 07 08 09 11 13 15 16 17 18 19 23 27 28 29 2E
34 36 37 38 39 46 47 55 56 57 65 66 68 69 71 75 76 77

VIN: WVWAF63DX48011311 Mileage: 161360km/100264miles
-------------------------------------------------------------------------------
Address 01: Engine Labels: 4D0-907-560-BGH.lbl
Part No SW: 4D0 907 560 CS HW: 8E0 907 560 
Component: 4.2L V8/5V G 0040 
Coding: 0007873
Shop #: WSC 01065 000 00000
VCID: 79F7E961335289D6DC9-5178

2 Faults Found:
17546 - Fuel Trim: Bank 2 (Add) 
P1138 - 001 - System too Lean - MIL ON
17544 - Fuel Trim: Bank 1 (Add) 
P1136 - 001 - System too Lean - MIL ON
Readiness: 0000 1001

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Address 02: Auto Trans Labels: 09L-927-760.lbl
Part No SW: 09L 927 760 C HW: GS1 9.0 4.1 *
Component: AG6 09L 4,2L V8 1003 
Coding: 0001102
Shop #: WSC 00000 000 00000
VCID: 37732F5945C65FA66AD-515A

No fault code found.

-------------------------------------------------------------------------------
Address 03: ABS Brakes Labels: 3D0-614-517.lbl
Part No: 3D0 614 517 AK
Component: ESP 5.7 allrad H33 0047  
Coding: 0008376
Shop #: WSC 01065 000 00000
VCID: 6BDBC329490E2B465E5-515A

No fault code found.

-------------------------------------------------------------------------------
Address 05: Acc/Start Auth. Labels: 3D0-909-13x-05.lbl
Part No SW: 3D0 909 135 K HW: 5WK 470 25
Component: Kessy 6400 
Coding: 0006376
Shop #: WSC 01065 000 00000
VCID: 2D5F0D31B79AE576001-515A

Subsystem 1 - Part No: XXXXXXXXXXX 
Component: ELV XXXX

1 Fault Found:
00165 - Switch for Transmission Position P/N 
007 - Short to Ground - Intermittent

-------------------------------------------------------------------------------
Address 06: Seat Mem. Pass Labels: 3D0-959-759.lbl
Part No: 3D0 959 759 B
Component: Sitzmemory D1 BF 1520 
Coding: 0000003
Shop #: WSC 01065 000 00000
VCID: 356F25515FCAADB6781-515A

No fault code found.

-------------------------------------------------------------------------------
Address 07: Control Head Labels: 3D0-035-00x-07.lbl
Part No: 3D0 035 008 M
Component: ZAB COCKPIT 0188 
Coding: 0500305
Shop #: WSC 01065 000 00000
VCID: 2449E815E450243EDFF-515A

No fault code found.

-------------------------------------------------------------------------------
Address 08: Auto HVAC Labels: 3D0-907-040.lbl
Part No: 3D0 907 040 G
Component: Climatronic D1 1144 
Coding: 0000002
Shop #: WSC 00000 000 00000
VCID: 2245EE0DFE442A0EAD3-5178

No fault code found.

-------------------------------------------------------------------------------
Address 09: Cent. Elect. Labels: 3D0-937-049-V1.clb
Part No: 3D0 937 049 G
Component: STG.Bordnetz 5001 
Coding: 0000002
Shop #: WSC 94825 999 53461
VCID: 2E5D0A3DBA9C9E6E39B-5178

2 Faults Found:
00978 - Lamp for Low Beam; Left (M29) 
010 - Open or Short to Plus
00907 - Intervention load Management 
000 - -

-------------------------------------------------------------------------------
Address 15: Airbags Labels: 3D0-909-601.lbl
Part No: 3D0 909 601 E
Component: 0G Airbag 8.4E+ H10 0934 
Coding: 0012359
Shop #: WSC 01065 000 00000
VCID: 254FF511EF6ADD36C81-5178

No fault code found.

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Address 16: Steering wheel Labels: 3D0-953-549.lbl
Part No: 3D0 953 549 E
Component: Lenksäulenmodul 3401 
Coding: 0000232
Shop #: WSC 01065 000 00000
VCID: 2F631739BD96976632D-515A

No fault code found.

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Address 17: Instruments Labels: 3D0-920-xxx-17.lbl
Part No: 3D0 920 882 A
Component: KOMBIINSTRUMENT RB4 0411 
Coding: 0007321
Shop #: WSC 01065 000 00000
VCID: 254FF511EF6ADD36C81-515A

2 Faults Found:
00470 - Combination comfort Databus in Single Wire 
011 - Open Circuit - Intermittent
00470 - Combination comfort Databus in Single Wire 
012 - Electrical Fault in Circuit - Intermittent

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Address 19: CAN Gateway Labels: 6N0-909-901-19.lbl
Part No: 6N0 909 901 
Component: Gateway K<>CAN 0101 
Coding: 0000006
Shop #: WSC 01065 000 00000
VCID: F0E15445E028489EEB7-5178

2 Faults Found:
00470 - Combination comfort Databus in Single Wire 
011 - Open Circuit - Intermittent
00470 - Combination comfort Databus in Single Wire 
012 - Electrical Fault in Circuit - Intermittent

-------------------------------------------------------------------------------
Address 28: HVAC, Rear Labels: 3D0-919-158.lbl
Part No: 3D0 919 158 F
Component: Klima-Bedienteil D1 0117 
Shop #: WSC 00000 000 00000
VCID: 2E5D0A3DBA9C9E6E39B-5178

No fault code found.

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Address 29: Left Light Labels: 3D0-909-157.lbl
Part No: 3D0 909 157 
Component: EVG GDL+AutoLWR(l) X012 
Coding: 0000001
Shop #: WSC 01065 000 00000
VCID: E6CD321DD2EC962E81B-515A

1 Fault Found:
01344 - HID (Xenon) Headlight 
012 - Electrical Fault in Circuit - MIL ON

-------------------------------------------------------------------------------
Address 34: Level Control Labels: 3D0-907-553-V1.clb
Part No: 3D0 907 553 B
Component: LUFTFDR.-CDC- 3C1V0 1101 
Coding: 0017700
Shop #: WSC 01065 000 00000
VCID: 264DF21D926CD62EC1B-515A

No fault code found.

-------------------------------------------------------------------------------
Address 36: Seat Mem. Drvr Labels: 3D0-959-760.lbl
Part No: 3D0 959 760 B
Component: Sitzmemory D1 F 1520 
Coding: 0000004
Shop #: WSC 01065 000 00000
VCID: 2D5F0D31B79AE576001-515A

No fault code found.

-------------------------------------------------------------------------------
Address 37: Navigation Labels: 3D0-919-887.lbl
Part No: 3D0 919 887 A
Component: NAVIGATION 0147 
Coding: 0400000
Shop #: WSC 01065 000 00000
VCID: 32651E4DAEA4BA8E5D3-5178

1 Fault Found:
00625 - Vehicle Speed Signal 
004 - No Signal/Communication - Intermittent

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Address 38: Roof Electronics Labels: 3D0-907-135.lbl
Part No: 3D0 907 135 B
Component: Dachmodul 0605 
Coding: 0000047
Shop #: WSC 01065 000 00000
VCID: 2245EE0DFE442A0EAD3-5178

1 Fault Found:
00220 - Connection to Sunroof 
004 - No Signal/Communication - Intermittent

-------------------------------------------------------------------------------
Address 39: Right Light Labels: 3D0-909-158.lbl
Part No: 3D0 909 158 
Component: EVG GDL+AutoLWR(r) X012 
Coding: 0000001
Shop #: WSC 01065 000 00000
VCID: E7D33F19D5E68F26BAD-5178

No fault code found.

-------------------------------------------------------------------------------
Address 46: Central Conv. Labels: 3D0-959-933.lbl
Part No: 3D0 959 933 F
Component: 0N HSG 0101 
Coding: 0000040
Shop #: WSC 01065 000 00000
VCID: 336B1B4951BEB386565-FFFF

Subsystem 1 - Part No: 3D1 959 701 D
Component: Tuersteuergeraet FS 0201

Subsystem 2 - Part No: 3D1 959 702 D
Component: Tuersteuergeraet BF 0201

Subsystem 3 - Part No: 3D0 959 703 D
Component: Tuersteuergeraet HL 0104

Subsystem 4 - Part No: 3D0 959 704 D
Component: Tuersteuergeraet HR 0201

Subsystem 5 - Part No: 3D0 909 610 B
Component: 3I HDSG 2320

Subsystem 6 - Part No: 7L0 907 719 
Component: Neigungssensor 0020


-------------------------------------------------------------------------------
Address 47: Sound System Labels: 7Lx-035-4xx-47.lbl
Part No: 3D0 035 465 
Component: 08K-AUDIOVERST 0111 
Shop #: WSC 00000 000 00000
VCID: DEBD1AFD0ABCCEEE49B-5178

1 Fault Found:
00872 - Bass Speaker Rear Left (R15) 
011 - Open Circuit


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## pgoober (Jan 4, 2009)

*could it be spark delivery?*

Rob, 

Given that you have been clearing codes and there is still an "intervention" code in there I wonder if it is a downstream effect of a wiring issue. 
Corrosion at the connect to the headlights?

You have the bass speaker issue (that many have and have had) and a short (maybe) in the headlights. 
Anything flickering?

I am guessing that the vehicle speed signal is a down stream effect of a disagreement between MAF and O2 and kicks on when the car nearly stalls.
Does it periodically nearly stall?

The fuel issue is too low during additive. So idle. Poor rubber or crack or poorly seated vacuum...somewhere....and not intermittent.
Also not Multi. Does this rule out an o2 sensor?

I am truly grasping.

-BD

I looked at your old thread at
http://forums.vwvortex.com/showthread.php?6143021-1st-VCDS-scan-MIL-Light-on-suggestions-Please

as well

There is the wiper fault in the older scan. Which seems to be cleared up. 
Are there pinched or frayed wires under/in the hood?


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## PanEuropean (Nov 3, 2001)

Sharbotcreek said:


> ...it runs rough for the first few minutes of clearing the codes.


That's entirely normal, my W12 engine, which is healthy, does the same thing. I think that all engines run rough for a few moments after codes have been cleared. Be aware that clearing fault codes from an engine controller also sometimes messes up the readiness code, so don't clear fault codes in the parking lot of the place where you plan to get the emissions test done. 



Sharbotcreek said:


> -------------------------------------------------------------------------------
> Address 17: Instruments Labels: 3D0-920-xxx-17.lbl
> Part No: 3D0 920 882 A
> Component: KOMBIINSTRUMENT RB4 04*11*
> ...


Having version 11 software in the instrument cluster is a known cause of many, many problems. There are defects in instrument cluster software with a version number less than 21 (for example, 0421, 0521, etc.) that cause problems with data transmission across the CAN busses. That software should be updated at your earliest opportunity. See this post for more details: Instrument Cluster (MFI, or Y24) - How to reset the Display Screen (Includes TB C-90-04-01 and TB 90-05-04)

Michael


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## PanEuropean (Nov 3, 2001)

pgoober said:


> I am guessing that the vehicle speed signal is a down stream effect of a disagreement between MAF and O2 and kicks on when the car nearly stalls.


Not so in this case. That speedsensor fault is spurious, it is a direct result of out of date software in the instrument cluster (it is at version 11, should be at version 21) and out of date software in the navigation CD reader (it is at 0147, should be at 0168).

Truth of the matter is that there is nothing wrong with the speedsensor. The navigation CD reader is reporting that fault because data packets that contain the speedsensor signal are getting dropped as they go through the (virtual) CAN gateway in the instrument cluster, and are transferred from the drivetrain data bus to the comfort data bus. Those two busses run at different speeds, the CAN gateway is, in effect, a router that directs traffic across the busses. The navigation CD reader is not getting the info it expects to get, and hence is reporting a problem with the speedsensor data. The problem is a packet-switching problem, not a problem with the speedsensor.

Michael


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## twgin (Apr 25, 2012)

I'm currently fighting P1130/P1128 codes (system too lean, both banks) that caused my 2006 to fail smog in California. I assume "swapped out" MAF sensors means new ones ? The only thing missing from your list is fuel injectors which in the case of my codes is listed as a possible cause on the Ross-Tech wiki.

Of possible interest on mine: a thorough cleaning of the MAF sensors made the codes go away for one whole day, appx 30 miles of driving with some lead footed stretches. The next day it coded only P1130 (too lean, Bank 2) and so far has continued this behavior. This is non intuitive as the air intakes of course meet up at the rear of the induction manifold; you wouldn't think MAF problems would pick one bank or the other. It suggests some other problem, perhaps the injectors, is present. Earlier on I drove through a few tanks of gas with SeaFoam additive to clean the injectors; no changes observed before or after. I am considering pulling the injectors and getting them professionally cleaned/tested.

Terry


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## cbh123 (Aug 25, 2013)

Generally speaking lean or rich is something reported by the O2 sensors, should be unrelated to MAF sensors.
The MAF measures air, the controller calculates appropriate fuel to squirt by injectors, then the O2 sensors report on the accuracy of the decisions made by the other 2 
 layman terms I think 

Whenever you get a too lean code, the most likely thing is unmetered air getting into the engine. 

Check for vacuum leaks, AFTER THE MAFs 

A bad O2 sensor could give a false report but normally they would have a fault code of their own also,,,


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## PanEuropean (Nov 3, 2001)

cbh123 said:


> Whenever you get a too lean code, the most likely thing is unmetered air getting into the engine. Check for vacuum leaks, *AFTER THE MAFs*


Hi Bruce:

That's a very sharp observation , thanks for suggesting it.

Michael


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## Sharbotcreek (Aug 25, 2013)

Thank you everyone for all your input.

Yes I changed both MAFs with no change whatsoever.
I will get the software updates as soon as I can, I have the car booked for a trans flush and reflash next week.

I do have an ultrasonic cleaner so I will pull and clean the injectors.

The fact that the fault is at idle is what is confusing to me. I have read other posts where it coded then was the fuel pump, but I have put over 30,000 kms on with this MIL on and car runs like a top. Averaging about 11 L/100kms and often getting in the 10's (about 22-26 miles per US gallon) which I figure is quite good for this car. 

In Ontario if I clear the codes then try to have it emissions tested they read the OBD port and will fail the car as it needs to go through many operating cycles with no MIL activated.

I have used propane at the egr and hoses after the mafs with no change, which leads me to believe there is no leak, however I don't have the equipment to do a smoke test, I guess that will be the next thing I have to do.

Thanks
Rob


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## PanEuropean (Nov 3, 2001)

Sharbotcreek said:


> In Ontario if I clear the codes then try to have it emissions tested they read the OBD port and will fail the car as it needs to go through many operating cycles with no MIL activated.


Hi Rob:

I kinda-sorta think that all that is needed to pass the Ontario emissions test is a readiness code with eight zeros in it. But, I might be wrong on that.

My thinking is that as long as the readiness code is eight zeros (all working well), then it is unlikely that the testing facility has the expertise to go digging into other engine fault codes that might have no effect on emissions. For example, if you had eight zeros in your readiness code, but a fault code present that said (for example) that one of the cooling fans was not working right, who would care? That would not affect emissions.

My suggestion is that you try and get the readiness code the way you want it (eight zeros), then take it in for the test, to heck with the other fault codes. Worst that can happen is that you lose $35.

Michael


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## Sharbotcreek (Aug 25, 2013)

Thank Michael that's a great idea, I never really thought too much into it, but you might be right as the OBD readings they take would be very minimal and not indepth like what is revealed with a VAG. I will do that asap, I will let you know.


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## PanEuropean (Nov 3, 2001)

Hi Rob:

Just remember, don't clear any faults (immediately before the emissions test) if the readiness code is eight zeros, because clearing faults tends to mess up the readiness code.

Michael


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## cbh123 (Aug 25, 2013)

I think you are allowed 2 drive cycles incomplete, to get a pass, not sure exactly, the older the car the more not ready codes you are allowed. For sure you cannot have the check engine light on. That is instant fail.


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## Sharbotcreek (Aug 25, 2013)

Check engine light came back on as I pulled into dealership for E-Test, definite fail if check engine light on


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## twgin (Apr 25, 2012)

Since Rob has put new MAF's on this is not the problem, but I disagree with Bruce's comment about bad MAF's not contributing to a lean code.

As I understand it, the controller will meter fuel to match what the MAF's are saying. If the MAF's are reporting 8 g/s of mass flow, the controller will meter the appropriate amount of fuel. If reality is 10 g/s mass flow, this is obviously a lean condition which the O2 sensors will pick up on and code. A good amount of these problems on the Ross-Tech forum are solved by new MAF's, even after trying to clean the old ones.

The same sort of thinking goes into suspecting the fuel injectors; if the controller is ordering a certain amount of fuel and the injectors are somehow plugged, a lesser amount of fuel will be delivered and cause a lean condition.

Rob's codes are generated saying "add" or additive (during idle) while mine are "mult" or multiplicative (during all phases), see this:

http://forums.vwvortex.com/showthread.php?1201806

One fellow on the Ross Tech forum solved this problem (after changing out just about everything else) when he discovered a crack in the exhaust manifold; air getting in messed up the O2 sensor reporting and caused codes. It seems this would only be a one bank problem though.

Resetting Fault Codes puts all Readiness Bits back to zero, some almost immediately go back to (1), some take a few days of driving. Ross-Tech has a script for resetting readiness on the 4.2l but I don't think anyone has ever tried it out and it is not included in the latest VagCom releases to my knowledge. I requested it a week or so ago but have not heard; guess I need to call them up...


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## cbh123 (Aug 25, 2013)

I tend to work with "likely" and "probable" when full info is not available.

When lean is reported by the system, all components are possible, but some are more likely than others. 

MAFs are reliable, outside of throwing a fault of their own. 
Same with O2 sensors, 
Same with injectors. 

10 year old rubber parts are less reliable. That is why I suggested check for vacuum leaks after the MAF, hoses, orings, and all the evaporative emissions stuff can be a problem with a lean code at idle. 

A small leak at idle is a significant problem, but at higher speeds, it may not be measurable. 

Don't rule anything out unless you have tested, or swapped with known good parts, but trouble shooting is a science and a methodical process. Keep posting and we will figure it out.

It is always obvious AFTER the solution is found


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## PanEuropean (Nov 3, 2001)

twgin said:


> Ross-Tech has a script for resetting readiness on the 4.2l but I don't think anyone has ever tried it out and it is not included in the latest VagCom releases to my knowledge. I requested it a week or so ago but have not heard; guess I need to call them up...


Ask and ye shall receive... 

Whatever Ross-Tech has done is essentially nothing more than automating (or perhaps prompting the driver through) the steps required to set the readiness code.

Generally speaking, there are two ways to set the readiness code in a healthy car:

1) Just drive it around as you normally would for a little while, and it will set its own code.

2) If you need to set the code in a hurry, follow the steps set out in the attached VW instruction sheet "How to set the readiness code in a 4.2 V8 Phaeton engine".

Michael


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## PanEuropean (Nov 3, 2001)

Rob:

The image below is an article that appeared in the June 2009 issue of 'MotorAge' magazine, a publication for automotive technicians. It's not a VW publication, but the information presented might help you find the cause of your problem.

Although the Phaeton is not specifically mentioned, I'm pretty sure that the 4.2 liter engine in the Audi is the pretty much same thing as the 4.2 liter engine in the Phaeton.

Michael


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## Sharbotcreek (Aug 25, 2013)

Thank you everyone, I will try to do some of this, this weekend. I will post what I come up with.

Cheers
Rob


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## twgin (Apr 25, 2012)

I found this post on an Audi forum:

<<start>>

I see this thread is a bit stagnant but there was no resolution posted and I think my reply may be useful for others who stumble upon this thread looking for help. 

I was recently fighting lean codes on BOTH BANKS of my 99 A6 with 2.8. It has 200k with the original o2 sensors so I figured replacing those would fix my fuel trims which had recently just jumped to -22%; my plugs were chalk white on all six cylinders. I installed new o2 sensors and saw no change so next I watched my MAF readings and they seemed reasonable (about 4.5g/s at idle and about 130 pulling hard). 

Next I guessed an air leak. I built a smoke machine from a tin can with mineral oil in it, a glow plug to heat it, creating smoke, and two air chucks, one connnected to my compressor and the other to my intake maniford (I pulled the line from my Fuel pressure regulator to connect to, pushed about 3psi of air through it into the manifold with the intake blocked at the MAF and look for leaks; it will leak through the valves of course but this still works really well.

It appears I had a visually good yet leaking suction pump. P/N 058133753B which has been superceeded by 058133753d due to common failures in the original.I read many threads about failing suction pumps but not many (if any) peg the symptom of Lean fuel trims on both banks. Considering the suction pump is plumed to the throttle body and there is manifold vacuum in the suction pump I think it's safe to assume a leak here could/would cause lean conditions along with poor idle and/or other related symptoms.

Since I just discovered this leak last night, I cleaned the body of the suction jet pump and then coated the seamed area where it was leaking with silicone and let it dry overnight. My fuel trim was >-20% when I left for work this morning and after 25 miles to work it had dropped to about -7% which is in spec. With this in mind, it appears that my suction pump was leaking just enough air to cause lean conditions, I had spark knock, and a slightly rough idle.

I post this for other VW/Audi owners who are experiencing lean fuel trim on both banks and cannot find any leaks in their vacuum hoses, consider your suction jet pump, they are well known for pluging (which causes the PCV system not to function, building pressure under the valve cover and promoting the o-so-common leaky cam tensioner seals), or falling apart in two pieces and it appears mine simply split and leaked without any visual signs.

Another consideration if your suction pump doesnt fix the lean on both banks issue, fuel injector seals dry out and harden over time, these are less than $1 each and fairly easy to replace. This is less likely since we are talking about lean conditions on "both" banks but I will discuss just in case. There are several ways to test before pulling your injectors, you can squirt water at the base of the injector while the car is running, squirt enough that it pools in the small recession in the manifold where the injector enters; if that water get's "drawn in" to the manifold, its becasue you've got leaky seals. If you change these, blow it out with air before pulling the injector incase theres any sand sitting at the base of the injector, you don't want that sand to fall in the manifold when you pull the injector.

<<end>>

Opens up a whole 'nother area of investigation...

Terry


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## remrem (Jan 20, 2008)

Good morning all,

I'm not trying to hijack this thread, merely searching for members who may have a particular skill set applicable to my current dilemma. I realize this thread refers to a V8, but it seems you are a well educated group when it comes to fuel mixture faults, O2 sensors, etc., so, if any of you have a chance to take a look at this thread for my W12, perhaps you could offer some insights, based on your experience and knowldedge of such things. Thanks very much in advance:



Here is the link: http://forums.vwvortex.com/showthread.php?6909671-Pre-catalytic-converter-issues


Best regards
Ron M.


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## Sharbotcreek (Aug 25, 2013)

Update! I got the car to pass emissions today, MIL will stay off for about 100kms and was enough time to get system ready and pass the test. MIL came on literally as I was leaving. One problem solved for a short period. I still need to figure out why I can't get to the bottom of it. I don't want to just keep replacing parts. Grrrr how I hate to love this car!


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