RPM going crazy at start

[RicardoM]

5 hours ago, nimbus said:

I think that i will send the car to garage on Monday, I will give you feedback later in the week.

A VAG-COM cable is much cheaper than a visit to a Skoda garage.

[nimbus]

7 hours ago, LightRain said:

Sorry I couldn't try and help you any further.

Its okay, you helped me already allot

[nimbus]

2 hours ago, RicardoM said:

A VAG-COM cable is much cheaper than a visit to a Skoda garage.

Will this work ? https://www.amazon.de/isYoung-Diagnosegerät-Fehlercodes-Funktioniert-Protokolle/dp/B07449157Z/ref=sr_1_1?ie=UTF8&qid=1507389463&sr=8-1&keywords=isYoung+OBD2

[LightRain]

2 hours ago, nimbus said:

Will this work ? https://www.amazon.de/isYoung-Diagnosegerät-Fehlercodes-Funktioniert-Protokolle/dp/B07449157Z/ref=sr_1_1?ie=UTF8&qid=1507389463&sr=8-1&keywords=isYoung+OBD2

 

That's a generic OBD2 tool, these can't do anything manufacturer specific, they can only read fault codes, delete them, and some can show live data of some sensors and such. They are a useful tool but I don't know if Skoda were making OBD2 compatible cars before EOBD came in.

VAG-COM is specialist equipment that can interrogate the computer and perform certain operations, tests and adaptations. It is very powerful and essential for anyone wanting to do serious work on VAG vehicles. VCDS is what VAG-COM became. Check out www.ross-tech.com for information and compatibility.

 

I would still check the voltage of the 5 V, harness connector side, supply pins of the throttle body and crank sensor, to ground. If you get a 5 V reading (I suspect you will) then the fault could very well be in the MAP connector, it was corroded after all, maybe the corrosion went deeper then just the contacts.

[nimbus]

16 hours ago, RicardoM said:

A VAG-COM cable is much cheaper than a visit to a Skoda garage.

I know i know  

10 hours ago, LightRain said:

I would still check the voltage of the 5 V, harness connector side, supply pins of the throttle body and crank sensor, to ground. If you get a 5 V reading (I suspect you will) then the fault could very well be in the MAP connector, it was corroded after all, maybe the corrosion went deeper then just the contacts.

I did it this morning, check the hall sensor connector ( located on the top of the gearbox ) i got 5V, i check the supply pins of the throttle body, i got 5v. I checked the c pin of the map sensor, i got 5V . Start the engine and let it run for 3-4min. Then i take a ride for max 50m, and the problems are back, rpm going up and down. And now ? should i went until i can get a vag-com cable, or moving to the garage of the next village ? i need my car for daily driving that's the challenge...

[nimbus]

1 hour ago, nimbus said:

I know i know  

I did it this morning, check the hall sensor connector ( located on the top of the gearbox ) i got 5V, i check the supply pins of the throttle body, i got 5v. I checked the c pin of the map sensor, i got 5V . Start the engine and let it run for 3-4min. Then i take a ride for max 50m, and the problems are back, rpm going up and down. And now ? Who is faulty the map sensor ? the throttle body ? i use the car for daily car, so what will be faster ? buying a vag-com cable, waiting for I got it and the check the error code, or moving the car to the garage of the next village ?  

 

[LightRain]

I understand your frustration, but at least the car functions, but yeah, better to get this diagnosed and fixed in case it is something more critical. Also, at least you can be quite sure you don't have any supply side problems. I can't tell you what is wrong, nobody can without evidence, any guess is just that a guess. I've said what I would start with but you can't do that with your meter. Can't you get someone to help you so you don't have to juggle holding probes in place or go to an electronics shop and grab a cheap set of narrow probes and crocodile clip leads?

 

Regarding VAG-COM, isn't there a Danish VAG forum where you could ask if there are any local people with the software? There is a British equivalent here and as far as I know it works out very well for people.

[RicardoM]

Buy this one.

VAG 409.1 USB Kkl Interface

[Jeggo]

You can have your throttle hold revs if your vacuum pipe is broken or fallen off. its a little rubber hose on the left side of the engine if its a 1.3

[RicardoM]

@Jeggo

Can you show us a photo of that "vacuum pipe" located very vaguely "on the left side of the engine" ?

[RicardoM]

On 10/8/2017 at 21:39, RicardoM said:

Buy this one.

VAG 409.1 USB Kkl Interface

I forgot to tell you that you need a laptop too. Hopefully you have one.

[LightRain]

16 minutes ago, RicardoM said:

I forgot to tell you that you need a laptop too. Hopefully you have one.

 

Plus the software, right? If it's VCDS, doesn't the shareware version limit you to passive actions and limited DTCs?

[Jeggo]

3 hours ago, RicardoM said:

@Jeggo

Can you show us a photo of that "vacuum pipe" located very vaguely "on the left side of the engine" ?

Would you not call this a vacuum pipe on the left side?

 

 

Heres a video of it holding revs when this magical rubber hose is disconnected.

 

[LightRain]

24 minutes ago, Jeggo said:

Heres a video of it holding revs when this magical rubber hose is disconnected.

 

Surely that's not particularly unusual behaviour? It's getting a bit more air than expected so the computer compensates for it.

The OP's condition was a little different than that though? More surging and less steady, at least that's how I interpreted it.

Although, once he opens the throttle a bit that tiny leak would become nothing and the engine would behave normal again. So it isn't outside the realm of possibility. But surely pipes and connections were visually checked at least before posting to a forum?

[Jeggo]

I thought it was just something worth mentioning. I have no idea what state the OP's car is in. Ive put my two cents in because when i bought my car this hose was disintegrated causing it to hold revs like the video. Its probably not the OP's problem but everything is worth a mention

[LightRain]

Absolutely, similar model and engine, so it's good input.

In hindsight, I hope he has already eliminated the easy stuff before moving on though. Or I'm going to feel bad for getting him to get the meter out

[RicardoM]

17 hours ago, LightRain said:

The OP's condition was a little different than that though? More surging and less steady, at least that's how I interpreted it.

Exactly. Not to mention the tendency of the engine to stall when the clutch pedal is pressed.

21 hours ago, LightRain said:

Plus the software, right? If it's VCDS, doesn't the shareware version limit you to passive actions and limited DTCs?

Umm... the little CD that accompanies the interface usually holds a fully ''licensed'' VAG-COM revision 409.1.

[LightRain]

Aaaah

[nimbus]

On 10/10/2017 at 19:37, RicardoM said:

I forgot to tell you that you need a laptop too. Hopefully you have one.

No sadly

 

On 10/10/2017 at 23:08, Jeggo said:

Would you not call this a vacuum pipe on the left side?

 

 

Heres a video of it holding revs when this magical rubber hose is disconnected.

 

I changed it because the rubber was in bad condition. But didn't help. ( also it has nothing to do with the problem )

 

23 hours ago, RicardoM said:

Exactly. Not to mention the tendency of the engine to stall when the clutch pedal is pressed.

Umm... the little CD that accompanies the interface usually holds a fully ''licensed'' VAG-COM revision 409.1.

Thats good if i can get the cable and the CD

 

 

Well I followed the idea of light rain by asking on a Danish VAG forum if somebody could come and check the codes, temperature contact was always in error even after cleaning the codes. And the throttle body was also faulty, so I send the car to the garage and there changed the throttle body with a used one and it works ( wasn't so expensive  ) Even if i would like to do it my self... Next time maybe  

 

 

Anyway, I didn't know that the temp. sensor can  do so much troubles

 

 

 

 

 

 

 

 

 

 

 

 

[LightRain]

So, it seems it was the throttle body?

It could just be coincidence about the temperature, I think the type (according to haynes diagram) of temperature sensor has two sensing units in it, one for the gauge and one for the ECU. In that case, maybe the only one to fail was the gauge one.

 

Anyway, I hope you are fixed and happy

[RicardoM]

Just patting myself on the shoulder 

On 10/7/2017 at 13:04, RicardoM said:

Could be as simple as a dirty MAP sensor, dirty TB or more serious as a faulty MAP sensor or TB.

[nimbus]

On 12/10/2017 at 19:58, LightRain said:

So, it seems it was the throttle body?

Yes

On 12/10/2017 at 19:58, LightRain said:

Anyway, I hope you are fixed and happy

Yeah its great to drive it again  

On 12/10/2017 at 20:39, RicardoM said:

Just patting myself on the shoulder