Be gentle while disconnecting since the plastic line going to the back of the engine can crack easily.

Where the screwdriver is the 13 mm vacuum line to double-check

 

@1eapplebaum I smoke test it again today follow what u said no leak at all...
and tonight I did a test drive it smooth as glass.. fuel trim is perfect..
that is weird.. the problem is intermittent
Maybe I just wait the Plug and New air filter come and see If it solve the problem...hizz

 

NG,

These numbers show a perfectly normal operation. I assume this was engine warmed or at op temps and idle?

3.5g/s is perfect air flow at 500rpm. To be at a 1.0 Lambda with only what appears to be a small switching variation is all you can hope for.

So, even though you're validating the MAF you still don't know a couple of things:

1. You don't know if you are losing some of the 3.5g/s before it gets to the cylinders (air leaks).
2. You don't know the state of fuel delivery of the injectors.

Regarding #2, I have to keep remembering I am on the Bentley forum and limited equipment available. Probably, if you suspect the injectors, the only option available to you is pulling them having them cleaned and bench flow tested. You will not have injector data, nor will you have access to examine any of those data.

Not sure what the petrol conditions are like in Vietnam. Here in the US, we have top tier fuel available to us as well as "cheap gas". Cheap gas lacks and detergent cleaning agents. Constant use of cheap gas will eventually take its toll on fuel injectors. Given the age of the car (how many years and miles it has been on the road) and maybe before you owned it (I assume you didn't buy it new), the injectors could be the problem, but trouble first showing up on one bank.

These now are becoming longer shots at P2190. If you cannot find an air loss after the MAF, and MAFs on the W12 are mounted WAY WAY upstream, so lots of potential, then all that's left is too much fuel delivery. Again, no fault of the ECU we can assume, since you've swapped them, pretty much the injectors are all that is left.

This is not likely a faulty intermittent wiring issue to the injectors as if we occasionally disconnected to the injector, that would flag a different P-code and would actually create a lean fuel condition not a rich one.

Fuel injectors would be rising in importance for me now.

 

@BWings in here we have Ron 95 while the car required Ron 98, I saw on the label on the fuel door.
I bought it used about 1 month.. the car has 50.000 miles on odo and first registered here in 2010 and was born in 01/2009.
Tomorrow I will buy some Fuel injector cleaner and see if it help..

the weirg thing is the problem running intermittent... sometimes it perfect.. some times it weirg.. mostly on cold start.
When it hot.. it become normal again about 90% of the time

 

NG,

One half step you can take and I only recommend this half-heartedly, is to try an injector cleaner through the petrol tank. There are a number of brands out there. Don't know what you would have available. My preferred tank additive is Chevron Techron. It must be the concentrate and not the plain injector treatment. If you can get it, that might be worth a try.

If you do try, follow the dilution recommendations. You can go a little higher, but avoid going over double dilution. Maybe try a few tanks of treated fuel. If no change, then consider the injector cleaning.

 

NG - By top tier fuel I am not referring to octane. Here in the US high or low octane fuel comes in either Top tier or cheap gas. YES, you should only be using 91/93 octane or 95/98 RON on that scale, but look into whether the fuel comes with a detergent additive from the pump. If not, you should be adding some detergent like Techron all the time.

 

@BWings Today I got the air filter sooner than I thought
but the problem still the same.. it random misfire at cold start then Fuel trim is way back to -25% at bank 2 until it got drive for about 20 miles
here is the video of what I'm recording

I put fuel injector cleaner also.. here is what they sell here





and finally it is my fault code log on bank 2

 

Hi NG,

So, a couple of things:

1. As I watch MAF performance on bank 2, the video started at ECT 46*C, this is already in closed loop (obvious by fuel trims), the MAF is commanding double the fuel @ 500-600RPMs as it should. Standard should be approx 3.0 grams/sec, most of the time the MAF is commanding 5.xx to 6 G/s. Twice the fuel needed for 6 cylinders and 3L. The fuel trims (O2 sensor) is reporting that and doing its job.

Bank 1, however, the engine was already warmed up considerably, but MAF readings are commanding rich but much closer to the target 3 G/L and bank 1 O2 sensors are reporting that. It wasn't until ECT reached 89*C (normal operating temperature) that the bank 2 command is settling down closer to the 3G/L target for 500 rpms at the very end of the video.

I know you said you've swapped MAFS side to side with same results, but something is causing Bank2 MAF to command double fuel to complete warmup. My focus still wants to be at the MAF. I think you posted in the past that you replaced the MAF connectors. The bank 2 MAF uses 5 wires as it also delivers the IAT signal.

2. With everything I am seeing in the video, I have more confidence in the fuel injectors Bank 2 now. They look to be doing what they should do and they are fueling to the double air volume command coming from the MAF. The old air filter looked really bad, the fuel injector cleaner is still useful and I would still run a couple of bottles of it in a couple of tanks of petrol. Did you verify fuel in Vietnam is a top tier fuel? If not, keep using the injector treatment periodically. I use Chevron Techron concentrate in my car twice a year, but I faithfully only use Chevron 91 octane fuel in my car which contains the same Techron already mixed in the fuel.

3. Also, I noticed your model year is 2009 and you are doing smoke tests for vacuum leaks. This was more primarily a 2003 to 2006+ model year problem, but sounds like your results were predictably positive. This really is not your problem.

In conclusion - Fueling is a simple matter of mixing air with fuel. In normal conditions and all sensors are good, the air/fuel should be the correct balance and given that nothing was ever changed in the EMS tables. Do you have confidence the ECUs were not changed for tuned ECUs by previous owner?

When a rich condition exists and all sensors are good it is one of three - too much fuel, or too little air (or both). In your case, air and fuel seem to be in the correct proportions but singling out the MAF sensor, it is showing twice the target delivery. If this were my car, I would still be concentrating on Bank 2 MAF. It is not performing to a known standard on warmup. Once ECT reaches operating temps it seems to settle down and report more correctly.

One comment I can make, when I replaced the connectors on my MAFS, I noticed the center pair of leads on the factory connector Bank 2 were braided. This is done sometimes because there is some "cross talk" in these signals. So, when I replaced mine, I also braided those two leads on the new connector. This can also be done because of RF/IR interference. I really do not know for certain.

Here is a pic of my olds ones:


You can see gray and black wires braided from the factory. It could be nothing, but I copied this in the new connector.

 

NG,

Something else I thought of, and since I do not know all that you've done to your car including maybe disconnecting batteries, do a throttle body alignment. This is a long shot, but maybe the TB on bank two is the problem and maybe no longer in alignment with Bank 1.

Here is the VCDS copy/paste. Follow directions carefully.I've done this alignment on my car, Even though Bentley is not mentioned, it works.




Throttle Body Alignment (TBA)


Ross-Tech is not responsible for any damage or problems that may result from following these instructions. They are to be used at your own risk. As always, you should refer to a Factory Repair Manual for your vehicle!

This procedure details how to perform a Throttle Body Alignment (TBA) on many VW/Audi vehicles. This procedure cycles the motorized throttle body through various states (idle, part throttle, WOT) to relearn their positions. Some examples of reasons to perform a TBA:

• The vehicle's battery has been disconnected and re-connected
• The ECU has been removed and reinstalled
• The Throttle Body has been cleaned or removed and reinstalled
• The Accelerator Pedal has been removed and reinstalled

In some vehicles, the car will not run correctly, or may not run at all without performing a TBA after one of the above operations. The TBA can be performed on both Drive-By-Wire (DBW or E-gas) as well as Cable-throttle cars as long as there is no Idle Stabilization Valve (ISV). If there is an ISV, then there is no motorized control of the throttle at all. Typically, '96-'99 VW/Audi have motorized Cable-throttle, and '00+ VW/Audi have DBW. Obviously, there are some exceptions. This should be obvious but TDI's do not have throttle bodies.
There are certain test conditions that must be met before doing a TBA:

• No DTC's in the Engine Controller
• Battery voltage at least 11.5 V
• Throttle must be at idling position (keep your foot off the gas pedal)
• Throttle body part must not be dirty (carbonized).
• Coolant temperature must be between 5 and 95C
• If fault codes were cleared cycle the ignition off and back on prior to running Basic Settings.

Contents

• 1 Cable-Throttle Engines
• 2 Drive-by-Wire (DBW) Engines using KW-1281
• 3 Drive-by-Wire (DBW) Engines using KWP-2000 or CAN
• 4 Drive-by-Wire (DBW) Engines using KWP-7000 (UDS/ODX)
  • 4.1 Special Notes
• 5 Video Link

Cable-Throttle Engines

(These are engines with a physical cable between the accelerator and the throttle, but WITHOUT an ISV.)

Turn the key on but do not start the car.

• [Select]
• [01 - Engine]
• [Measuring Blocks - 08]

Enter Group 098 (Note: Some SIMOS or Marelli ECU's use Group 001 such as ADY & AEE engines)

• [Go!]
• [Switch to basic settings]

Once you do this you will see the top right display say ADP RUN. The TB adaptation is being done as soon as you switch to basic settings. You will see the values change and hear the TB cycle for the first few seconds then it will stop. Leave it in Basic Settings for about 30 seconds.

• Click the [Switch to Meas. Blocks] button and you're all set.

Be sure not to touch the accelerator and make sure the engine is NOT running when you do this!



Drive-by-Wire (DBW) Engines using KW-1281

(These are engines WITHOUT a physical cable between the accelerator and the throttle. Check to see if the engine speaks KW-1281 by looking in the top left of the Open Controller Screen Some examples of KW-1281 engine controllers are 2000+ Golf/GTI/Jetta/New Beetle/Audi TT 1.8T)

Turn the key on but do not start the car.

• [Select]
• [01 - Engine]
• [Measuring Blocks - 08]

Enter Group 060

• [Go!]
• [Switch to basic settings]

Once you do this you will see the top right display say ADP RUN. The TB adaptation is being done as soon as you switch to basic settings. You will see the values change and hear the TB cycle for the first few seconds then it will stop. Leave it in Basic Settings for about 30 seconds.

• [Switch to Meas. Blocks] button and you're all set.

Be sure not to touch the accelerator and make sure the engine is NOT running when you do this!



Drive-by-Wire (DBW) Engines using KWP-2000 or CAN

(These are engines WITHOUT a physical cable between the accelerator and the throttle. Check to see if the engine speaks KWP-2000 or CAN by looking in the top left of the Open Controller Screen. An example of a KWP-2000 engine controller is the 2002+ B6 Audi A4 1.8T. Some examples of CAN engine controllers are the Mk5 Golf 2.0T FSI)

Turn the key on but do not start the car.

• [Select]
• [01 - Engine]
• [Basic Settings - 04]
• Group 060
• [Go!]

It should say "Basic Settings: OFF" on the top of your screen.

• Click [ON/OFF/Next] to turn on Basic Settings.

It should now say "Basic Settings: ON" on the top of your screen. Once you do this you will see the top right display say ADP RUN. The TB adaptation is being done as soon as you switched basic settings on. You will see the values change and hear the TB cycle for the first few seconds then it will stop. Leave it in Basic Settings for about 30 seconds.

• Click [[b]ON/OFF/Next] to turn off Basic Settings.

It should now say "Basic Settings: OFF" on the top of your screen

• Click the [Done, Go Back] button and you're all set.

Be sure not to touch the accelerator and make sure the engine is NOT running when you do this!

If it did not complete, or resulted in Error, see the Special Notes below.

Drive-by-Wire (DBW) Engines using KWP-7000 (UDS/ODX)

Check to see if the engine speaks KWP-2000 or CAN by looking in the top left of the Open Controller Screen. UDS modules do not support conventional Measuring Blocks - 08 so that button will be grayed out. They do not support conventional Adaptation - 10 or Basic Settings - 04 group numbers, so all choices are found in drop-down menus in these modules.

Make sure the coolant is warm. Turn the key on but do not start the car.

• [Select]
• [01 - Engine]
• [Basic Settings - 04]
• Chose a variant of Throttle Valve Adaptation from the drop-down list
• [Go!] to activate the Basic Settings
• After the result of Finished Correctly appears click [Stop]

The TB may cycle for the first few seconds then it will stop. Leave it in Basic Settings for about 30 seconds.

• Click the [Done, Go Back] button and you're all set.

Be sure not to touch the accelerator and make sure the engine is NOT running when you do this!

Special Notes

• In some engines, before doing a TBA, it may be necessary to cycle the ignition off and back on after clearing faults.
• On vehicles that use Cable-Throttle systems, an over adjusted (or sticky) throttle cable can cause the TBA to fail, or symptoms like no CCS (Cruise Control System) operation.
• On vehicles that use Cable-Throttle systems the idle may be erratic after the TB has been removed and cleaned, even after a successful TBA. It may be necessary to drive the vehicle normally for a while until the system has re-adapted.

 

@BWings how can u know the Bank 2 MAF command double the fuel to complete warm up?
I saw both MAF bank 1 and BANK 2 reading with the same g/s

One thing I notice is when I turn on the ignition, right after I start the car the LTFT on bank 2 read way back to -25

my MAF on bank 2 conector was broken because of heat.. so I replace it with new one plus I added some heat sink over the Wire because my Bank2 MAF has broken wire insulator.. & I was fixed it correctly, It never pop up fault code for MAF anymore

 

LTFTs always stay stored in volatile memory and will pick up where they left off. You can erase them by removing battery power to the ECUs. This will erase all stored in volatile memory including fuel trims. Fuel trims will then restart fresh when you reconnect battery power to the ECUs. I was reluctant to suggest that as disconnecting power to the entire car causes a host of other resets. The ECUs are fused. I've not tried clearing FTs on this car and don't know if pulling the ECU fuses will accomplish the same. If you do that, leave the fuses out for several minutes. An hour is better.

If you missed my other post about TB alignment, wait on it until you erase FTs. In other words, erase FTs, reconnect power, then do the TB alignment, then start the car and test everything.

 

@BWings I did the throtle body alignment by ODIS it is much easier compare with VCDS.
I got my car battery replacement 1 month ago when I bought it. I did an AGM for main battery and the smaller one for Starter battery

Do u think Bad Spark plug can cause weirg fuel trim reading? I 'm sure the previous owner didn't replace the right plug for it.
It is VAG NGK not the Double Platinum NGK as we Saw now.

 

Just follow the live data in your video. The first 2/3rd of the video was only bank 2. You want to match 3 items

1. RPM (Important! The formula is 1 gram/sec air flow per Litre @ 500RPM, so 3L requires approx 3g/s @ 500 rpm)
2. ECT
3. MAF output.

When any engine cold starts, RPMs are much higher than 500. The ECU follows a table ECTs vs. Time = RPM output. If you look immediately at data on cold startup, the MAF output in g/s will obviously be much higher to match RPM. Wait until RPM settles to 500 RPM before matching MAF output target 3g/s. Your video started already reaching warmup target idle of 500- 550. ECT started out at 48*C, past the normal cold start warmup to closed loop. CL was already accomplished and rpm 500 but MAF showed double fuel.

Here is an example of a typical cold startup RPM table in degrees F. This is a different car where final idle RPM are a little higher than Bentley, but the same principle:

 

@BWings I will order another MAF for make sure it work..
the previous owner replace both MAF also... I don't know if it still keep the old one.

 

Spark plugs should not matter, but this is an example of so many variables that it is like trying to diagnose a problem online with a blindfold.