Well now you're just daring me to go off on one my geeky and exhausting explanations. Weekend's coming, I might have time to do a lengthier dissertation then.MoRS6+ wrote:I'm loving all this!
. . . . . . without geeky and exhausting verbal explanations is frankly marvellous!
When to replace MAFs?
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RS6-4dr911
- 1st Gear
- Posts: 55
- Joined: Sun Jan 25, 2009 12:34 am
- Location: Houston, TX, USA
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RS6-4dr911
- 1st Gear
- Posts: 55
- Joined: Sun Jan 25, 2009 12:34 am
- Location: Houston, TX, USA
Not sure I understand your request. Are you wanting the raw data or log blocks 1, 2 and 3? I didn't log the exact same items in the before and after and I'm logging individual items using Adv. Meas., not the simple blocks of four. Let me know what you want and I'll try to gather, and I'll provide a detailed, scientific analysis just to demonstrate my geekiness.Shoppinit wrote:Cool. WOuld be useful if you could post the 1, 2 & 3 groups for a direct comparison with previous value.
Just wanted to compare like with like. Only really interested in what your g/s and lambda values are doing. I don't remember seeing any advanced measuring blocks option... I feel like we're using different version of the same software - you're missing a turbo button, and I'm missing the advanced measuring blocks.
Is it an option that's right there on the measuring blocks screen, like the turbo button?
Is it an option that's right there on the measuring blocks screen, like the turbo button?
Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."
If you're still running too lean then:
1. there must be unmetered air coming in
2. MAFs are reading wrong
3. Lambda sensors are toast
4. You're running dodgy fuel. Unlikely given where you live
Where did your MAFs come from? Are they genuine Bosch?
1. there must be unmetered air coming in
2. MAFs are reading wrong
3. Lambda sensors are toast
4. You're running dodgy fuel. Unlikely given where you live
Where did your MAFs come from? Are they genuine Bosch?
Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."
Also, if you run the car too lean for long then you'll kill the O2 sensors, so try to get to the bottom of this before going much further.
Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."
the MAFs were from Audi and were exchange units. Audi dealer fitted them.
Would a vacuum leak cause it to be lean as they changed all the vac hoses when they had the airboxes off.
As mentioned before, they changed the lower seating and seal for both MAFS so they should be tight, and the upper O rings were new in March. The O2 sensors never gave a problem before the MAFS were changed so either the MAFS were both shot out of the box, there is a leak or the air box is not fitted properly, or the vac hose is not tight somewhere????????
I have been logging block 32 on VAGCOM and it shows the correction applied and if it goes over 10% it is beyond normal limits, mine does go over 10% but i still think it can correct for this....I hope as running lean means running hot which can lead to cracked cylinder heads etc.....
Would a vacuum leak cause it to be lean as they changed all the vac hoses when they had the airboxes off.
As mentioned before, they changed the lower seating and seal for both MAFS so they should be tight, and the upper O rings were new in March. The O2 sensors never gave a problem before the MAFS were changed so either the MAFS were both shot out of the box, there is a leak or the air box is not fitted properly, or the vac hose is not tight somewhere????????
I have been logging block 32 on VAGCOM and it shows the correction applied and if it goes over 10% it is beyond normal limits, mine does go over 10% but i still think it can correct for this....I hope as running lean means running hot which can lead to cracked cylinder heads etc.....
Sounds like either a vacuum hose hasn't been connected, or incorrectly connected. What are your additive trim percentages like?
Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."
Code: Select all
032,0,Lambda Control (Mixture Adaptation)
032,1,Adaptation (Idle),Bank 1 Sensor 1,Range: -25.0...+25.0 %\nSpecification: -7.0...+7.0 %
032,2,Adaptation (Partial),Bank 1 Sensor 1,Range: -25.0...+25.0 %\nSpecification: -7.0...+7.0 %
032,3,Adaptation (Idle),Bank 2 Sensor 1,Range: -25.0...+25.0 %\nSpecification: -7.0...+7.0 %
032,4,Adaptation (Partial),Bank 2 Sensor 1,Range: -25.0...+25.0 %\nSpecification: -7.0...+7.0 %Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."
have you still got the old MAFs? Maybe try swapping them back. I've had mine out loads of times. Doesn't damage the seals if you're careful. Plus might be that your seals are the problem. You could try swapping MAF 1 and MAF 2, too.
If columns 1 and 3 are OK, that points towards bad MAFs rather than vacuum leak. Weird.
If columns 1 and 3 are OK, that points towards bad MAFs rather than vacuum leak. Weird.
Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."
I heard that it'll work for a bit, but then it'll degrade quicker again. You can find brand new (EDIT: BOSCH - you're asking for trouble with anything else) MAFs for much, much less than Audi quote for them. Just need to do a bit of research.
Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."
I dont have old MAFs as the ones I got were exchange.
Reviewing the vagcom logs it seems that the highest values in columns 2 and 4 are when the load is low so this would indicate zero boost and therefore a leak in the vac system. If the load is high, the boost climbs and the vac system becomes pressurised so any leaks are not as relevant.....and the lambda correction drops down to within spec!
How difficult is it to remove the airboxes - how many screws and is it a simple lift off....
Reviewing the vagcom logs it seems that the highest values in columns 2 and 4 are when the load is low so this would indicate zero boost and therefore a leak in the vac system. If the load is high, the boost climbs and the vac system becomes pressurised so any leaks are not as relevant.....and the lambda correction drops down to within spec!
How difficult is it to remove the airboxes - how many screws and is it a simple lift off....
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