View Full Version : Log files.. misfire and low MAF readings

01-10-2007, 09:00 AM
http://home.comcast.net/~existential/images/Johnny.CSV one of the guys on the other forum I belong to put it on this site for me, i dont have a camera so this is the only way i thought to do it.. if you dont mind take a look thanks..

01-10-2007, 09:48 AM
Checked out your log but, I really can't say what's happening.

It would have been better if you logged measuring blocks 003, 020 and even 031.

That will at least give me throttle position, ignition timing, correction factor for each cylinder and some ballpark O2 values when timing correction occurs.

Throttle position will tell me when you went WOT.
Ignition timing will tell me your actual timing at all times.
Correction factor will show if the timing values were reduced at all and which cylinder it occured on.
O2 values can give a hint of a rich or a lean condition. (although they are ballpark figures at best)

01-10-2007, 09:52 AM
Im new to this log crap..lol.. there are only 3 slots on my vag-com program with 003 i didnt see the MAF readins could have been wrong i wanted to see what misfires I had so the first two slots where for those.. i can run another log not that big of a deal.. what blocks should i run?

01-10-2007, 09:56 AM
See here: http://www.ross-tech.com/vag-com/m_blocks/index.html

003 will give you: RPM/Air Mass/Thottle Pos/Timing

020 will give you: Correction factor on Cyl1 - 4

031 will give you: O2 voltage before cat and O2 voltage after cat (if you had a V6 or V8, this would also include the other two sensors as well)

01-10-2007, 10:01 AM
so those are the ones I should run.. but im getting a misfire is cyl2 and cly3

01-10-2007, 10:12 AM
I understand but, it would be nice to see the relationship between throttle/timing/correction.

I took another look at your log file again and I see that the majority of your misfires are showing when the MAF readings are starting to decline. This indicates that you have let off the gas.

According to the Bentley Manual: "Ignition misfires are to be expected due to operation conditions (e.g. warm-up, deceleration shut-down), misfire recognition is deactivated"

So when I see your MAF readings drop and the misifres occur, your misfire recognition readout is showing "deactivated" and doesn't toggle back until you return to part-throttle. The only thing that I'm unsure of is whether misfire recognition "deactivates" under WOT as well.

01-10-2007, 10:14 AM
well I will run some other logs with those blocks and try and post them up, I would suspect you know more then I do, I dont really understand the values and what they mean yet..

01-10-2007, 10:38 AM
Daft is a good guy to listen too, he knows his stuff, and has helped many other people (such as me) understand things much better than i did before...

i didnt look at your log yet by the way...