Hi all,

My vRS CR diesel is now 3 months old, has 6k miles under it's belt and to date hasn't missed a beat - I'm lovin' it.

However this afternoon I was trundling along a street close to home, doing about 30 in 3rd at light throttle, when it suddenly lost power. It was only for a fraction of a second, like I'd lifted off and then immediately reapplied throttle... except I hadn't. It recovered immediately (no lights on the dash or any other symptoms whatsoever) and didn't do it again - carried on running in it's usual smooth responsive manner. Also it's worth adding I'd been running around town for a while so the engine was up to full operating temperature.

Has anyone ever experienced a similar "blip" or know what might have caused it? I'm wondering whether maybe a bit of water or some other contaminant may have got into the diesel. Hoping it is something like that and it doesn't end up in the workshop.

Cheers,

Bob

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Sounds similar to what I have experienced in this thread:

http://briskoda.net/forums/topic/150025-negative-g/page__hl__negative

However I guess that you were just driving on the flat.

Hmmm... that's not the best

Have you got access to anything to read live data off the car (CAN compliant EOBD USB dongle, VAGCOM/VCDS etc.)? I know it's a long shot, but if you do then i'd hook up the laptop, and have it graph at a minimum: Revs (just for reference), TPS input & short term fuel trim, then i'd go for a drive and see if i can recreate the problem.

Ideally i'd also (the cheaper (free) software i've used only allows 3 graphed values) graph a few others if the software supports it: MAF & Air intake temp, (pre-cat) O2 sensor & Coolant temp.

Crank & cam sensors if they're available to read.

Assuming you don't have access to that, then some random pot shots (these are probably the most common in general for diesels):

• Fuel filter blockage, on the move or otherwise underperforming
  
• Water in the fuel
  
• Throttle Position Sensor on the road out
  

You can visually inspect the fuel filter area, does anything look awkward? Wetness, excessive rusting, loose connectors, pipes at jaunty angles etc.

The TPS can kind of be measured with just a multi meter, i'm guessing it'll be a dual track item (have a google for where it's wiring loom plugs into the ECU -- this is going to be easier to access & test, also it will account for a chaffed wire between the ECU and the TPS, which testing the TPS itself wont...) you'll need an assistant. Your looking for a linear progression on resistance as you press the pedal. Both tracks should progress at the same speed.

Crank and cam sensors you could unplug, and with a tin of £1.99 switch cleaner out of maplins and a clean tooth brush give the contacts and plug a clean then positively reconnect.

If it ever happens again, i'd change the fuel filter, no questions asked. Good for your car anyway, doesn't cost much, should change it frequently anyways.

Interesting problem they're just a pig to identify though

Sounds similar to what I have experienced in this thread:

http://briskoda.net/...e__hl__negative

However I guess that you were just driving on the flat.

Very interesting that thread Griffo - I had also just gone over a brow and was heading downhill, so definitely follows a pattern with what you and the other guys have experienced. That has put my mind at rest somewhat as it seems it may be a "feature" of the car rather than a fault! I think tomorrow I'll follow the same route a couple of times and see if it happens again.

Cheers,

Bob

--

Hmmm... that's not the best

Have you got access to anything to read live data off the car (CAN compliant EOBD USB dongle, VAGCOM/VCDS etc.)? I know it's a long shot, but if you do then i'd hook up the laptop, and have it graph at a minimum: Revs (just for reference), TPS input & short term fuel trim, then i'd go for a drive and see if i can recreate the problem.

Ideally i'd also (the cheaper (free) software i've used only allows 3 graphed values) graph a few others if the software supports it: MAF & Air intake temp, (pre-cat) O2 sensor & Coolant temp.

Crank & cam sensors if they're available to read.

Assuming you don't have access to that, then some random pot shots (these are probably the most common in general for diesels):

• Fuel filter blockage, on the move or otherwise underperforming
• Water in the fuel
• Throttle Position Sensor on the road out

You can visually inspect the fuel filter area, does anything look awkward? Wetness, excessive rusting, loose connectors, pipes at jaunty angles etc.

The TPS can kind of be measured with just a multi meter, i'm guessing it'll be a dual track item (have a google for where it's wiring loom plugs into the ECU -- this is going to be easier to access & test, also it will account for a chaffed wire between the ECU and the TPS, which testing the TPS itself wont...) you'll need an assistant. Your looking for a linear progression on resistance as you press the pedal. Both tracks should progress at the same speed.

Crank and cam sensors you could unplug, and with a tin of £1.99 switch cleaner out of maplins and a clean tooth brush give the contacts and plug a clean then positively reconnect.

If it ever happens again, i'd change the fuel filter, no questions asked. Good for your car anyway, doesn't cost much, should change it frequently anyways.

Interesting problem they're just a pig to identify though

No not got access to any of that stuff I'm afraid - although I do have loads of "old school" tools like spanners (my other car is a 1974 Triumph Stag) . However thanks for the good advice about checking connections under the bonnet so I'll have a look as soon as the rain lets up. It did also occur to me that something may have got wet that shouldn't.

Cheers,

Bob

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As said int hat other thread, mine does this too and has for the whole of its 30k miles. The dealer had no idea, so anyone got an answer yet?

As said int hat other thread, mine does this too and has for the whole of its 30k miles. The dealer had no idea, so anyone got an answer yet?

My 2010 Octy VRS CR has the same problem. In the dealer on Wednesday . The engine also hunts on a very light throttle.

Dealer said it is no aware of any others withn this problem. They have had the EGR gasket fail on several so maybe this is the problem.

There seem to be certain situations...

I have a 1.9 PD 105 and in one single situation up to now, standing at a crossroad going left and acceleration pretty hard , I also experienced one single less-than-a-second loss of power....never happened again up to now, also not on this particular crossroads.... The fuel tank was half full so I don't think the fuel pump scratched the bottom of the barrel....

I wouldn't be too concerned as long as it doesn't occur regularly....

Edited 20 March, 201016 yr by Octavia1Z

It doesn't just occur regualry - it happens all the time. The road 'hump' needs to be of a certain size, though I have not stopped to carry out any geometry calculations so can't say what size, but around the 'stomach lifting' feeling size. It feels as if the power has been taken fully off, or that the brakes have been applied.

Is it always only diesels? No petrols experiencing this?

I have a petrol vRS (TFSI - 2008 model) which has been fine. A few months back I had a test drive in a new CR and noted that at gentle cruising (30-40mph) it would occasionally 'jolt' almost like a momentary misfire on a petrol engine. I doubt this is anything to do with fuel or fuel filter because the problem is so short-lived. More likely 'something' is causing one or more injectors not to fire for a split-second.

Never had that - this is not the same as the issue we are discussing, the car you were driving presumably had a specific injector, or ECU, fault

Never had that - this is not the same as the issue we are discussing, the car you were driving presumably had a specific injector, or ECU, fault

OP wrote: doing about 30 in 3rd at light throttle, when it suddenly lost power. It was only for a fraction of a second, like I'd lifted off and then immediately reapplied throttle.

Sounds a lot like what I experienced.

I had this on my 07 Oct y vRS Diesel. It happened quite a bit and once actually stalled whilst driving. Engine light also came on and stayed on for a few days. Then the DPF light came on and luckily was on way home so got it regenerated and it went off.

Took it into the dealer and they said there was an error with a Differential Pressure Sensor. Changed it and manually regenerated the DPF again and since then its been fine.

Hi all,

My vRS CR diesel is now 3 months old, has 6k miles under it's belt and to date hasn't missed a beat - I'm lovin' it.

However this afternoon I was trundling along a street close to home, doing about 30 in 3rd at light throttle, when it suddenly lost power. It was only for a fraction of a second, like I'd lifted off and then immediately reapplied throttle... except I hadn't. It recovered immediately (no lights on the dash or any other symptoms whatsoever) and didn't do it again - carried on running in it's usual smooth responsive manner. Also it's worth adding I'd been running around town for a while so the engine was up to full operating temperature.

Has anyone ever experienced a similar "blip" or know what might have caused it? I'm wondering whether maybe a bit of water or some other contaminant may have got into the diesel. Hoping it is something like that and it doesn't end up in the workshop.

Cheers,

Bob

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Has anybody had any more solutions to this problem. My new VRS is holding back and hunting worse than ever.

Dealer can't find anything but it's very annoying and spoils the drive.