[1.6 fsi] - Misfire or something else

Hi Mac,

I also found this, which I am guessing you must have seen before:


In all honesty, when looking at 033 (potentially Short-term trim as it is called) it reacts in the same manner as in most of the other cars I have seen, i.e., bouncing around 0 mostly and reacting to throttle instantly.

It would be really helpful yes. Especially in combination with other DTCs or measured values.
 
Evripidis said:
Hi Mac,

I also found this, which I am guessing you must have seen before:


In all honesty, when looking at 033 (potentially Short-term trim as it is called) it reacts in the same manner as in most of the other cars I have seen, i.e., bouncing around 0 mostly and reacting to throttle instantly.

It would be really helpful yes. Especially in combination with other DTCs or measured values.
Click to expand...
There was no VCDS label file for the FSI/BAD until last year, so any published info on VCDS FSI/BAD Groups is very unlikely to include the FSI/BAD engine.
I'll stick with the label files as my source, (unless logged data contradicts it).
Right now, I have no idea about Groups 032 & 033, so I'll not speculate.
Once 032 & 033 have been logged, we'll, (hopefully), know if they do refer to fuel trim. I hope so, as I agree that is something we are missing.
Mac.
 
Lots of the groups are generic across many vag engines, and I think the Lambda fuel trim ones are included in this, I’ve used them on my FSI to diagnose false air
 
Indi said:
Lots of the groups are generic across many vag engines, and I think the Lambda fuel trim ones are included in this, I’ve used them on my FSI to diagnose false air
Click to expand...
@Indi
Can you explain what the two blocks, in Groups 032 and 033, in the FSI/BAD file mean, and how to interpret them, especially to identify air leaks, and fuel trim please?
Here's what they look like, (engine not running).
Mac.

32,33,34 VCDS Measuring Blocks - FSI ECU.png

(Once again, acknowledgements to @Andrew for the screen shots).
 
PlasticMac said:
@Indi
Can you explain what the two blocks, in Groups 032 and 033, in the FSI/BAD file mean, and how to interpret them, especially to identify air leaks, and fuel trim please?
Here's what they look like, (engine not running).
Mac.

View attachment 130872
(Once again, acknowledgements to @Andrew for the screen shots).
Click to expand...
I think the lambda control learning values are the lambda adaption that the ECU changes in order to compensate for lean or rich air fuel ratios, though I don’t remember them being labelled as sum and product

Basically the trim values that the car applies to the injector open times to compensate for a lambda that isn’t what it is expecting

This is all from memory and it’s been a while since I’ve looked at it, I’ll plug in VCDS and see at the weekend if I get a chance
 
1730461806067.png

This is what I remember seeing on my FSI, full VCDS
Group 32 not 33 though
two values, one for idle trim and one for under load trim
image just found from google
 
Indi said:
View attachment 130874
This is what I remember seeing on my FSI, full VCDS
Group 32 not 33 though
two values, one for idle trim and one for under load trim
image just found from googleThe label file text has been known to be wrong, so "sum" and "product" might not be relevant.
Click to expand...
@Indi
The label file text has been known to be wrong, so "sum" and "product" could be an error.
The alternative, without them, seems logical.

That VCDS screen shot is from a BNS turbo V8 ... I think.
Mac.
 
Evripidis said:
@PlasticMac Hi Mac, they relate to the terms "additive" and "multiplicative". Have a read here:

Fuel Trim Info - Ross-Tech Wiki

wiki.ross-tech.com wiki.ross-tech.com

I know it seems to be long-winded but have a go and you will see what I mean. I cannot explain it any better.
Click to expand...
That is a very good explanation.
So, if there's a large air leak, we'd expect both Blocks 1 & 2, (Group 032), to show a significant positive %.
A very small leak would show a significant positive % in Block 1, (idle), but not so much in Block 2.
Is that about right?
Mac.
 
PlasticMac said:
That is a very good explanation.
So, if there's a large air leak, we'd expect both Blocks 1 & 2, (Group 032), to show a significant positive %.
A very small leak would show a significant positive % in Block 1, (idle), but not so much in Block 2.
Is that about right?
Mac.
Click to expand...
There is a ross tech video with an example with the dipstick.
 
I have not been able to reset the value 32.2 no matter what. I will try disconnecting the bat.

If my reasoning is correct, and by excluding all else, it can only be injectors.
 
Evripidis said:
I have not been able to reset the value 32.2 no matter what. I will try disconnecting the bat.

If my reasoning is correct, and by excluding all else, it can only be injectors.
Click to expand...
The resetting of fuel trims has been mentioned before, long time ago. I remember trying it myself, and, like you, it doesn't reset.
Mac.
 
Resetting codes repeatedly does the trick for the 0032.1, 0033.1 but nothing for the rest.

From a system control/firmware standpoint, the long-term value could be resetting but only internally in the form of a model parameter. But the displayed value having so much "inertia" will take some driving to alter.

In any case, the reading on mine, if correct, does show a very lean condition that the ECU is trying to make up on the long term. It is marginal (10% either side is the limit I think) for throwing an error code and I will not keep on driving it.

It kind of feels like it is suffering when in traffic.
 
Evripidis said:
Resetting codes repeatedly does the trick for the 0032.1, 0033.1 but nothing for the rest.

From a system control/firmware standpoint, the long-term value could be resetting but only internally in the form of a model parameter. But the displayed value having so much "inertia" will take some driving to alter.

In any case, the reading on mine, if correct, does show a very lean condition that the ECU is trying to make up on the long term. It is marginal (10% either side is the limit I think) for throwing an error code and I will not keep on driving it.

It kind of feels like it is suffering when in traffic.
Click to expand...
That’s odd, my understanding (and from my vague memory as well) is that resetting the codes should reset the fuel trim too…
 
The long-term partial won't budge.

I can't sort it now because I had a motorbike accident and I am trying to find parts. My only reliable means of transport at the moment.

I have to get injectors for it is my next step, probably.
 
Indi said:
That’s odd, my understanding (and from my vague memory as well) is that resetting the codes should reset the fuel trim too…
Click to expand...
They should, but they don't seem to.
You, me, and @Andrew discussed it last year.
I posted a before and after screen shot, iirc.
Mac.
 
PlasticMac said:
The label file text has been known to be wrong, so "sum" and "product" could be an error
Click to expand...
Good Afternoon,

At the time when me, you and Seb were building the A2OC label file there was a longish discussion about this, look back it may show why we ended up with the terms 'sum' and 'product'. It was mainly between you and Seb, Seb seemed knowledgeable and I kept a low profile not knowing anything about Lamda (still don't - never attempted to familiarise myself) but 'sum' and 'product' may have been me trying to shorten the text from 'additive' and 'multiplicative' to keep things neat, after all it does have the connotation of addition and multiplication. Maybe the word 'product' is a too old school, I wonder if they still teach in basic arithmetic that the product of 3 and 4 is 12.

I thought at the time this would come back to haunt us, when you all have this sorted out I will amend the label file.

Andy
 
Andrew said:
Good Afternoon,

At the time when me, you and Seb were building the A2OC label file there was a longish discussion about this, look back it may show why we ended up with the terms 'sum' and 'product'. It was mainly between you and Seb, Seb seemed knowledgeable and I kept a low profile not knowing anything about Lamda (still don't - never attempted to familiarise myself) but 'sum' and 'product' may have been me trying to shorten the text from 'additive' and 'multiplicative' to keep things neat, after all it does have the connotation of addition and multiplication. Maybe the word 'product' is a too old school, I wonder if they still teach in basic arithmetic that the product of 3 and 4 is 12.

I thought at the time this would come back to haunt us, when you all have this sorted out I will amend the label file.

Andy
Click to expand...
It’s labelled as idle and partial in full fat VCDS
 
Andrew said:
Good Afternoon,

At the time when me, you and Seb were building the A2OC label file there was a longish discussion about this, look back it may show why we ended up with the terms 'sum' and 'product'. It was mainly between you and Seb, Seb seemed knowledgeable and I kept a low profile not knowing anything about Lamda (still don't - never attempted to familiarise myself) but 'sum' and 'product' may have been me trying to shorten the text from 'additive' and 'multiplicative' to keep things neat, after all it does have the connotation of addition and multiplication. Maybe the word 'product' is a too old school, I wonder if they still teach in basic arithmetic that the product of 3 and 4 is 12.

I thought at the time this would come back to haunt us, when you all have this sorted out I will amend the label file.

Andy
Click to expand...
Given that it took nearly twenty years after FSI production ended, to get a label file, the odd "anomaly" is forgivable, I reckon.
I too had not given much attention to Lambdas, until now.
Riveting stuff though.
Mac.
 
You must log in or register to reply here.
Back
Top