GolfGTIforum.co.uk
Model specific boards => Golf mk4 => Golf mk4 TDI => Topic started by: richandhazel on 17 March 2006, 16:01
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Did a test of my MAF sensor today with VAGCOM. This was the best run, full throttle up a dual carriage, 4th gear, changing to 5th:-
RPM MAF MAF EGR
    Req Act
2541 770 760 4.8    4th gear accelerating up hill
2604 850 770 4.8
2667 850 850 4.8
2751 850 825 4.8
2814 850 790 4.8
2898 850 775 4.8
2961 850 765 4.8
3045 850 770 4.8
3087 850 770 4.8
3150 850 765 4.8
3213 850 765 4.8
3276 850 765 4.8
3339 850 750 4.8
3402 850 755 4.8
3465 850 740 4.8
3528 850 740 4.8
3591 850 735 4.8
3654 850 740 4.8
3717 850 735 4.8
3780 850 725 4.8
3822 850 725 4.8
3885 850 715 4.8
3150 810 590 4.8
3087 850 1005 4.8  Change to 5th gear and continue accelerating up hill
3087 850 1005 4.8
3108 850 685 4.8
3129 850 660 4.8
3129 850 670 4.8
3129 850 675 4.8
3150 850 690 4.8
3150 850 705 4.8
3171 850 720 4.8
3171 850 735 4.8
3192 850 745 4.8
3192 850 750 4.8
3213 850 750 4.8
3234 850 750 4.8
3255 850 755 4.8
3276 850 760 4.8
3297 850 755 4.8
3318 850 755 4.8
3339 850 745 4.8
3360 850 750 4.8
3381 850 750 4.8
3423 850 745 4.8
This is the test:
At 3000 rpm full load (test can only be done while driving) the reported air intake quantity should be at least 800 mg/stroke
It looks like my MAF is not reaching 800 and therefore requires replacement.
Just wondered what peoples thoughts are and whether you think that the MAF is sufficiently underperforming that it will make a big difference to overall performance.
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Just keep it in 5th while accelerating up a hill :grin:
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Can you do the MAF test with the free version of VAGCOM, as that's all I have?
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Not sure if you can do it with the free version. Mine is fully registered.
Incidentally, for future reference, I changed the MAF sensor and haven't really noticed any difference. I would conclude that although the sensor was underperforming and probably going bad, it wasn't bad enough to cause any noticeable difference at this stage.
Therefore those figures will need to look a lot worse before you notice a drop in performance and need to change it.
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you can measure your MAF readings with the free version :smiley:
me and a mate tried it out on my 130 the other day; couldn't make head or tail of the results though!! :laugh: though it looked like my MAF was doing the job :smiley:
Only annoying feature is that it only records the information for 3 minutes and then resets with a message telling you to buy the full version!!
Might have to invest in that next year as the free version made me realise how cool VAG COM is :nerd:
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If you've got someone with you, makes it a lot easier. Even with what you are saying about the free version, as long as your mate is monitoring the results that should suffice to prove/disprove the MAF operation.
The actual MAF should get somewhere near to the required MAF. As you can see from my results, mine was a little low but obviously not bad enought to warrant changing.........even though I changed it anyway :rolleyes:
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I'll have to have another go and post up the results; gives me an excuse to open her up :wink:
From what i remember the actual MAF readings were well above what was required ; I'll have to dig out my last results to double check :undecided:
Did you get your VAG COM direct from Ross Tech?
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No, I bought mine from a colleague at work. He sold his VW so passed the software and lead on to me.
I'd be interested to see your results.
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what measuring blocks did you use when testing the MAF? Just want to be sure I'm measuring the same blocks so as to give an accurate comparison.
But this is what was recorded previously. However, it was just playing about and not keeping it in one gear.
Engine speed MAF (specified) MAF (actual)
790-870 230-310 210-350
/min mg/str mg/str
1659 355 382.2
1638 250 470.4
1617 260 333.2
1617 290 284.2
1617 315 318.5
1638 430 401.8
1659 455 450.8
1680 435 455.7
1680 300 298.9
1659 250 480.2
1638 250 499.8
1617 265 396.9
1617 330 328.3
1617 320 308.7
1617 265 264.6
1596 250 460.6 - this amazes me because it's well over the required limit!! :shocked:
1575 250 494.9
1554 250 494.9
1533 250 504.7 - twice as much!!
only posted a fraction of what was recorded but you get the picture. My question is though; is my car overfuelling?? :undecided:
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Revs are too low and what gear were you in?
Need to put the engine under load, 4th gear accelerating hard, foot to the floor stuff :smiley:
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...sorry to hi-jack, but how much is the full version of VAGCOM you all speak of?
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Too much for you to consider. :smiley:
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hmm.
least my turbo works properly.
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:laugh: :laugh: mine does too now knobshot. Will chat to you tomorrow about it. :wink:
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I've had another look at the spreadsheet that you sent me. I'm guessing that you must have a different version of VAGCOM to me as I don't recognise that screen.
However, there is only one place that I can see a specified MAF of 850 so I assume that is the only time you went full throttle. What gear were you in? I suspect it may be a lower gear as your revs go quite high. To properly test the MAF I'd say that you need to be in 4th at least.
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...sorry to hi-jack, but how much is the full version of VAGCOM you all speak of?
Have a look here:-
http://www.ross-tech.com/
You may find it on ebay cheaper.
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i was in a mixture of 2nd and 3rd gear. I'll try 4th next time and report back. THanks for the feedback :smiley: