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1.4TSI 122BHP starting issue

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dombricka

New member
Location
Tallin, Estonia
Hi,

I have this problem that's becoming common (it used to be sporadic).
In the morning when I start the car, it starts just fine but when I release the clutch pedal the rpm starts to go down until the car starts trembling and it stops completely. Weird thing is that if I depress the clutch pedal again when it starts to tremble, the RPM goes back up to normal. I suspect it might have something to do with the start/stop system. Any ideas?
 
R

Ronin3

Ready to race!
Location
South Yorkshire
A cold start is probably too soon for the stop/start system to be activated.

I had a trembling issue with my car - same engine as yours - so I decided to change the spark plugs myself. I know VW say they will last 40k but I'm glad I changed them when I removed them.

The car feels much better to drive - no hesitation - no vibrations - uses less fuel.

I'd let VW just have a look at your car while its under warranty.
 
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dombricka

New member
Location
Tallin, Estonia
Sure, but frankly I very much doubt it. I also read it could be the PCV valve, but that has nothing to do with depressing the clutch. I still think it's a temperature sensor associated to the start/stop system that fails to correctly identify the low engine temp in the morning and thinks it's warm enough to cut it off. I will try to depress the start/stop button when the engine's RPM start to go low, see if it prevents it from stopping.
 
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Datastorm

Passed Driver's Ed
Location
Southampton, UK
I noticed mine trembled a little upon starting last weekend from cold. Difference is I have a 7-spd DSG box, assume this phenomenon is applicable to both manuals and autos?

This is the first time the car felt a little different upon starting, and it hasn't done it since.... hoping it's just a one off occurrence.
 
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dombricka

New member
Location
Tallin, Estonia
I think it's this stupid start/stop system. However, it didn't do any problem since, so I had no chance in trying to turn start/stop off and see what's what.
 
dr_mat

dr_mat

Go Kart Champion
Location
Berkshire
Start stop won't operate for a short period after startup, no matter what the temperature sensors say - it's based on wall clock time.

And if the start/stop decides to stop the engine, it will stop. It pulls fuel and spark, how can it carry on?

I find it weird that you say it bogs down when you take your foot off the clutch though. You, of course, mean whilst the gearbox is still in neutral, right?
The ECU does have awareness of the clutch position and when you lift the clutch while the car is in gear it will blip the throttle slightly and raise rpms even if you don't touch the throttle. If you lift the clutch in neutral and the start/stop has not yet engaged then the engine does nothing and continues to idle as normal.
 
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dombricka

New member
Location
Tallin, Estonia
If I depress the clutch while the RPM is starting to go lower and lower (as low as 700 RPM and then it starts trembling before stopping), the RPM goes right back again. If it was a faulty spark plug, it'd do this trembling no matter if the clutch was pressed or not.

I know how start/stop works, but I'm saying that it is malfunctioning somehow. It would be a good indication if I could turn off start/stop while the engine starts to manifest the issue, but I didn't get the chance so far.
 
dr_mat

dr_mat

Go Kart Champion
Location
Berkshire
dombricka said:
If I depress the clutch while the RPM is starting to go lower and lower (as low as 700 RPM and then it starts trembling before stopping), the RPM goes right back again. If it was a faulty spark plug, it'd do this trembling no matter if the clutch was pressed or not.

I know how start/stop works, but I'm saying that it is malfunctioning somehow. It would be a good indication if I could turn off start/stop while the engine starts to manifest the issue, but I didn't get the chance so far.
Click to expand...

That is very weird.. And yes, obvious one is to attempt to disable start/stop.

It sounds like it's easy to reproduce though so if they do it in the garage while the diags are plugged in it should be reasonably obvious what's going on.

I have seen older cars suffer from run-on when the engine stops, but that completely went away the moment they invented direct fuel injection. There's simply no fuel in the cylinders unless the ECU decides to put some there..

The trembling is presumably just the engine dropping its revs so far it can no longer run smoothly and it's about to stall.
 
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dombricka

New member
Location
Tallin, Estonia
Today it did it again, and the start/stop button being depressed made no difference. Only the clutch pedal does. Unfortunately, my wife who uses the car on a daily basis didn't get the chance of taping it. I will try to get it on tape tomorrow, fingers crossed, maybe I get lucky.
However, I didn't expect this from Golf. Everybody keeps praising it as being the leader in its class and all, but I just don't think it's normal for "the best" to have problems when it's only one year and 7000 km old.
 
dr_mat

dr_mat

Go Kart Champion
Location
Berkshire
Need to get the diags checked while it's doing it..!
Take it to your dealer, it's under warranty.
 
dr_mat

dr_mat

Go Kart Champion
Location
Berkshire
They couldn't reproduce it? I had the impression it happens every time ..
If you don't get any error codes you'd have to watch the measuring blocks data while it's doing it to hopefully spot what's not right ..
 
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