GTD Erratic Idle

[tonydon41]

Has anyone else had any intermittent problems with the engine ticking over at 1100 to 1200 rpm following a motorway cruise?
It's happened a couple of times in the last week and makes crawling in motorway hold ups a nightmare.
The engine is fully warmed up and all electricals like air con and heated seats/mirrors/rear window are off.
After about half an hour of holding the clutch half in to stop the car running away frustration got the better of me and I decided to stamp on the accelerator in neutral in the hope that this might cure the problem but it refused to rev over 2500 rpm.
The car is a month old and the problem started after about 1800 miles.

[monkeyhanger]

Not sure about the car's refusal to get over 2500 revs (unless you mean the car wouldn't rev over 2500 revs in neutral - perhaps it has a rev limiter for idling, never tried pushing the car to 2500 revs in neutral).

A higher idle speed when fully warm sounds exactly like the car was undergoing a DPF regeneration to burn off built-up soot, and you coming to a stop midway made it more obvious that the car was undergoing one with the higher idle. If you've done 1800 miles in a month, the car should be doing plenty of journeys long enough to burn the soot passively - recently you've perhaps interrupted a regen that the car is keen to finish.

[Silvadadi]

+1 for thinking you're in the middle of a dpf regen.

My left quad has shrunk since choosing a DSG.........not tried it myself in the GTD but iirc when in Octavia vRS at work if handbrake was applied revs were deffo limited.

If it's not a regular occurrence/problem then I reckon that's what's going on

[C2K]

It's a DPF regen for sure, will be rock solid at 1100 rpm. Mine seems to like to do them after I come off the motorway, you spend long periods at low load cruising so it's not so unexpected albeit ill timed.

It's all about duration sadly, revving the engine won't speed it up. You can't rev over 3K in neutral anyway, I remember trying this in the test car - don't bother subjecting mine to that.

[monkeyhanger]

I suspect that much of the time now when the fans are blaring after a long drive with ideal DPF regen conditions, it's not so much about carrying on a regen as much as cooling the DPF following that drive, rather than letting it cool on its own. Previous TDIs with DPF have never run on at the end of a long journey which was ideal for passive regen, but the MK7s DPF unit is closer to the engine than ever before (supposedly helping it get hot quicker and stay hot for the purposes of burning soot).

[mcmaddy]

Hasn't someone said previously that our mk7s don't do passive regens. They don't need to any more as vw have moved the location of the dpf as MH has said.

[tonydon41]

Since my original post I have noticed a pattern of behaviour on my journey home each day.
After about 10 miles I come off the motorway and sometimes there's a queue but the problem never happens here. After about 3 more miles there's always a queue for traffic lights and every day it happens at this point. The revs rise and the auto stop/start symbol appears in the top right corner of the display with a line through the symbol. The next time I stop about a mile later the problem has always miraculously cured itself!
With regard to the DPF regen I would understand this would be needed if I was constantly pottering around town on lots of short journeys but after 2500 miles in 6 weeks from new with quite a heavy right foot I would be surprised to find the car decides the filter needs unblocking on a daily basis.

[GolfDriver]

Hi,

I noticed this on mine also, the car is only a couple of weeks old and has around 1000 miles on the clock.

When stopped at lights the stop/start function didn't kick in, and the car was idling at around 1100 rpm.

I pressed the off button on the climate control and the engine immediately cut out (Stop/Start function) - I then pressed the clutch to start the engine again and the car idle at about 800 rpm

Nothing more than the car looking after itself in these cold days I think... but check to see if yours does the same.