A few technical faults

[skodayouth]

I have 3 major faults with my car that my dealership wont fix because there are no error logs from the ECU. Does this make anyone else cross, just because there are no error logs doesent mean I dont have problems,

I have VAG-COM myself and fair enough there are no logs which I appreciate makes it difficult to investigate, but to do nothing annoys me.

First problem with the car is when sitting at Idle, in park, neutral or drive the revs will suddenly drop to around 400RPM and then go back to a normal idle state, this occurs about twice a day, the "jerk" from the engine when this happens is noticable and has had me worried a few times, 3 times this week it has stalled because of this. This happens most on hot days or when the car has been driven spiritedley, never happens when cold

Second problem is that when cold (IE Temp needle hasnt moved off the stop) if you set the cruise control at exactly 40mph (Gearbox is usually in gear 5) the engine judders violently and continuously until you turn off the CC, you can maintain the same speed on the throttle no problems, does not occur when the engine is warm.

Third problem is the tiptronic auto, if approching a roundabout in 3rd (In "D") as you apply throttle to pull away the gearbox jerks violently (sometimes very violently) into 2nd unless you apply the most feathery amount of throttle (not ideal on a roundabout). This issue occurs all the time when the box downshifts to second while power is applied

Yet again, no ecu faults recorded so no one can address the problem, apparantley dealership spoke with SUK who have said there are no known faults of this type

I don't know what to do to resolve these problems, what does one do to diagnose a fault that isnt logged in the ECU. I have driven the car with my mate checking the VAG Com, the engine always seems okay, the gearbox tempreatures (80-90c) and solenoid selections always look good, and the CC fault is a total mystery, and so specific to being at that speed

To my limited knowledge these faults could be related to throttle position sensor, can anyone confirm this? As far as I am aware the engine is a MK4 golf motor and the tiptronic is from Octava II 1.6 and 2.0FSI, any known faults with these that anyone is aware of?

[Adrianh1]

I have little technical knowledge and certainly no knowledge of the first and last faults. But I would not think it a good idea to set the cruise control on a car when the engine is cold. A cold engine needs a variety of revs to warm up properly. You are probably putting the engine under too much strain too early.

[Taxi 219]

Sorry but maybe old news but didn,t Skoda do a recall on Throttle Position Sensors for those?

Hope you sort the problems out

[skodayouth]

Sorry but maybe old news but didn,t Skoda do a recall on Throttle Position Sensors for those?

Hope you sort the problems out

It's been confimed mine was not affected by this, only thing ever done was the Parking Sensor Update

As for the CC issue it shouldnt be under any stain, the ECU should automatically select an appropriate gear and correct amount of throttle no mater what the situation. Every day I pull out of work onto a 40MPH Dual Carriageway and this is how I noticed the problem, 5 sounds like a high gear but this box shifts into 5 at just over 30mph

[Little Jo]

I'm not a techie, but I can't help wondering if your issues are all related to one underlying fault, possibly an issue with the fuel supply. What sort of revs is the engine doing at 40mph in fifth gear? What sort of revs is it doing as you approach the roundabout? Are all problems more evident if the engine is cold?

An engine starved of fuel momentarily will stutter. My Fabia was just four months old when we had a fuel injector fail. The car started running on 3 cylinders and sounded very rough. When it failed we had a warning light come one, but your issue may not be bad enough to trigger an error code, but bad enough to affect the driving performance under the conditions you describe.

Solving the fault will almost certainly be dependent upon being able to reproduce the fault with a mechanic in the passengar seat. If necessary seek the assistance of another garage.

Intermittent faults are the worst kind, but I would be suprised if your faults were all down to one basic gremlin.

I hope you get sorted soon.

[skodayouth]

Just an update......

Had a poke around on Erwin today, there are two documents relating to the 1.6 BTS Engine that seem to relate to my issues

I cant post the specifics because Erwin is paid for and copyrighted but its along the lines of known issues with Improper reaction of the BTS engine to acceleration (runs too lean) after cold start and also Ignition cut outs – petrol engines

Maybe now this information is avaliable I will ask my dealer to take another look, the acceleration on cold start just requires an ECU Software update:thumbup:

[Guest]

Mr Youth, sounds like you could be onto something. I read your post and fairly quickly thought it could be a fuel air problem causing these difficulties as Jo indicated. Very possibly a faulty engine management sensor in the air system somewhere sending incorrect info to ecu when cold. Please let us all know what the outcome is.

Edited 24 August, 2009 by Estate Man