Anyone spot the problem?

[Frustratedracer]

Did a couple of logging sessions this afternoon to try and get to the bottom a very irritating problem.
Car was in D, started logging at about 40mph using a reasonably gentle push on the throttle.
Can anyone see anything wrong with these figures?

Graham

[Shoppinit]

Logs look ok. Maybe one weak MAF bank one. Maybe both, but hard to tell unless the log goes to redline under WOT.

What's your problem?

[Frustratedracer]

Thanks Shopp - 5.30am reply... do you never sleep?
Problem is this:
Drive along in D, 40mph. Apply what i would call 'medium' throttle (not enough to make it change down to 3rd).
The car accelerates but not smoothly, not exactly lurching but somewhere in between,a kind of stuttering if that makes sense?
It feels like either a misfire or it can't decide what gear to be in and is fluctuating between 2 gears.
If i do the same in tiptro which locks it in 4th, problem doesn't show, and I can't seem to replicate it in any other gear/rpm.
There are no fault codes and i have replaced the coil packs and plugs so i think my misfire theory is out the window.
From what i can see from the logs the TC always seems to be regulating when this happens but i assume it will be at this speed/rpm?
Any ideas?

[srichards]

Actually I was thinking mine was doing exactly that the other day as well. I was following 40mph traffic and they kept slowing down for no reason so I was crossing back over and under 40mph and it seem to create some sort of weirdness. I'm assuming it's due to the torque converter lock up at that speeds as it must lock it up then your speed falls then it unlocks it and that's why there is some odd behaviour? It definitely does it in D.

Does it do anything similar in S mode? I'd think it wouldn't.

[simonpoulton]

Any flashing of the ESP light? When my MAFs were playing up, it was causing that stuttering similar to what you described, but also flashing the ESP. I think it was metering the air wrong and then thinking the engine / power was higher than what it actually was...

The MAFs have a build date on so might be worth popping the airbox off an seeing if they are original. My ones managed 96k and 13ish years.

[Frustratedracer]

Simon,
No flashing of the ESP light and i cant see a build date on the MAFs.
I certainly haven't replaced them in the 4 years ive had the car. Its on 135,000 so if they are original they might be a bit dodgy.

[Shoppinit]

Is it a standard map? On 98/99 octane?

[Frustratedracer]

It's a Viper map

[Frustratedracer]

Run on Tesco 99

[Jayjay101]

Simon,
No flashing of the ESP light and i cant see a build date on the MAFs.
I certainly haven't replaced them in the 4 years ive had the car. Its on 135,000 so if they are original they might be a bit dodgy.

I'd check the mafs on Vag Com mate as I had this kind of problem on mine the box was all over the place and not very smooth al all!and it was the mafs.i changed both mafs-maf seals and found a broken wire on the plugs to the mafs.after all that was changed smooth as silk now.


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[Shoppinit]

Can you do some logs in turbo mode going up to red line, there isn't really enough data to determine if there are anomalies.

Hesitation like that could be due to bad N75 or the ÉCU pulling the ignition timing for whatever reason. Maybe bad fuel. You can log the ignition timing <beep>.

[Frustratedracer]

I can confirm it's not the MAFs. Just put 2 new ones on and no difference - starting to try my patience.
Shopp, i will do some logs and post them up.

[Shoppinit]

Huh. It censored re-tard. Retarded.

[Frustratedracer]

Shopp, what is going to give me best data:
Stick it in D and run through the gears WOT to redline or put in tiptro, 4th gear and do the same?

[Shoppinit]

Whichever most reliably reproduces the issue.

Does it even do it on WOT or is it only happening at partial load?

The turbo mode on VCDS will greatly increase the sampling rate giving a better chance of spotting any anomalies.