I have a starting problem and I think I need a Skoda centre with a good reputation for solving electrics problems - by thought rather than trial and error. Can anyone recommend one near Worcestershire?

The car: Octavia II (2005) Ambiente 1.6 Fsi, about 25k miles. No previous problems.

The problem: First thing in the morning, insert key, switch on ignition, pause for usual warning lights to go out, attempt start - just one go of about one engine revolution, but doesn't fire. Brake lights flicker. Withdraw key, brake lights still flicker but cease within 30 seconds. Key in, etc, and car starts immediately, as it normally does for the rest of the day (although not so today when it is raining). Exhaust gas warning light sometimes remains on (like today), sometimes not, but doesn't seem to correlate with the starting issue and nor is there any 'limping'. No other warning lights showing.

With due deference to Skoda and other VAG forums, I had the stop light switch replaced yesterday but the problem persists, unchanged.

Three VAGCOM codes indicate problems with brakes (2) and fuel pressure (1) but, once the car has started, all seems to be well with every aspect of driving.

Heigh ho! Clearly, this could end in big expense before all options tried, including the dreaded 'replace ECU', so I need a Skoda electrics expert who isn't going to waste time and money just guessing.

Does anyone have any ideas about the problem and the best source of help?

I'd recommend Ben at Shark Performance - a bit of a drive for you (M5-M6-A42/M42) but he really knows his stuff...

Sounds like a bad earth.

Does the high level brake light flicker too?

From memory this has a different earth point.

I'd recommend Ben at Shark Performance - a bit of a drive for you (M5-M6-A42/M42) but he really knows his stuff...

After seeing the recommendations on this forum, I've looked at Shark P's web site. Do they speak to ordinary mortals, like me, who don't drive high performance cars?

Something closer would be better but, if I have to, I'll be prepared to drive a long way.

Many thanks for the suggestion.

Sounds like a bad earth.

Does the high level brake light flicker too?

From memory this has a different earth point.

It is the high level brake light that I can see reflected in my garage door and driving mirror when I am starting (or failing to start) the car. I don't yet know if the 'normal' stop lights also flicker. There is some (not much yet) evidence that damp weather makes things worse and this, perhaps, is more suggestive of a 'short' than a poor earth - do you agree? I guess I need to find where the high level lights are earthed. I'll also get my wife to help out next time so that I can find out if both sets of brake lights are flickering. I'll feed in more info as I get it.

Many thanks to both of you for your help.

Hi opoman.

How about:

http://www.vwrescue.co.uk/

It bay far for thee me mon.

Hi opoman.

How about:

http://www.vwrescue.co.uk/

It bay far for thee me mon.

Good suggestion for close proximity (37 miles). Have you had personal experience of their quality in electrics fault finding?

Sounds like a bad earth.

Does the high level brake light flicker too?

From memory this has a different earth point.

Test now done. Both high and low stop lights flicker.

Good suggestion for close proximity (37 miles). Have you had personal experience of their quality in electrics fault finding?

Electrical fault finding specifically , No, they do however have a good reputation locally overall.

Might be worth a punt if nothing else appeals ?

Test now done. Both high and low stop lights flicker.

Probably best to find a good independent auto electrician in your area. They proper ones will have all the kit for fault reading and more besides.

Used a guy in Edinburgh after the towbar fitter made a wee bit of a hash of the electrics. His knowledge and expertise was a revelation. Now the cars out of warranty I know where I'll be taking the Scout should it develop electrical gremlins.

Obviously no good to you if you're not a Central Belter, but an illustration that the answer may be in a modest garage unit not too far away.

Niall

PS 25k in 5 years! Seriously? My car can only dream of such a relaxed life.....

OK. This is a guess, but I would check the earth point at the LH 'A' pillar. IIRC, this is the point where the pump is eventually earthed and it can be subject to water ingress.

You could also follow the wiring from the brake lights as far as you can.

If you need to take it somewhere, find a local auto electrician.

PS 25k in 5 years! Seriously? My car can only dream of such a relaxed life.....

2 years old when I bought it, with 1300 on the clock! Since retirement, I do less than 10k per year but lots of unhealthy (for both us and the car) short shopping trips.

OK. This is a guess, but I would check the earth point at the LH 'A' pillar. IIRC, this is the point where the pump is eventually earthed and it can be subject to water ingress.

You could also follow the wiring from the brake lights as far as you can.

If you need to take it somewhere, find a local auto electrician.

The LH 'A' pillar is the vertical support at the windscreen position on the driver's left (near side) - is that correct? The pump is the fuel pump, right?

Please forgive my ignorance - I grew up fixing cars from the age of carburetters and simple electrics. I flounder in the face of what goes on nowadays.

I'll give some thought to an auto electrician and try and follow the wiring back from the rear cluster and the upper stop light manifold.

Incidentally, talking to my neighbour about the problem revealed that he and his mates had driven VW commercial vehicles which, if there was any problem with the rear lights, would refuse to start!

Many thanks for your thoughtful responses, all of you.

OK. This is a guess, but I would check the earth point at the LH 'A' pillar. IIRC, this is the point where the pump is eventually earthed and it can be subject to water ingress.

You could also follow the wiring from the brake lights as far as you can.

If you need to take it somewhere, find a local auto electrician.

A further thought. Is there a relay involved in the brake light supply? In particular, a relay which, when powered, interrupts the supply to the brake lights? Turning the starter would drop the voltage, the held-off relay would falter and allow stuttering power to the brake lights, thereby creating the flickering.

Grasping at straws but I don't have a wiring diagram.

I read elsewhere on here that when the brake pedal is pressed the fuel supply is automatically cut off, so heel/toeing isn't possible.

Sure that could be related...

I read elsewhere on here that when the brake pedal is pressed the fuel supply is automatically cut off, so heel/toeing isn't possible.

Sure that could be related...

Now *that* is very interesting. So something is telling my system that the brakes are being applied - this sets off the brake lights and cuts off the fuel so that I can't fire the engine up. This effect that you describe must be subtle because, otherwise, the engine would stall when you brake.

Now *that* is very interesting. So something is telling my system that the brakes are being applied - this sets off the brake lights and cuts off the fuel so that I can't fire the engine up. This effect that you describe must be subtle because, otherwise, the engine would stall when you brake.

I'm not exactly sure how the process works, and it'd be best if someone else comes along to confirm what I've read. I'm going to test it out tonight in my car, see what happens!

After seeing the recommendations on this forum, I've looked at Shark P's web site. Do they speak to ordinary mortals, like me, who don't drive high performance cars?

Something closer would be better but, if I have to, I'll be prepared to drive a long way.

Many thanks for the suggestion.

I can confirm they do speak to ordinary mortals, as Ben is also an auto-electrician not just a tuning expert! I took my Octavia 2.0 TDI to him with an ECU fault which he fixed and was very happy with the outcome!

It was a long drive for me too, but in the end well worth it.

I read elsewhere on here that when the brake pedal is pressed the fuel supply is automatically cut off, so heel/toeing isn't possible.

Sure that could be related...

So you're decending a hill with your foot on the brake, and it cuts off the engine? I hope not!

Some cars may cut the THROTTLE (or go into limp mode) if you heel/toe, but this implies you are pressing the throttle.

I believe you have to hold the brake and throttle for a period of time (10s) to cut the ENGINE on some cars. If you cut the engine you would lose power steering/brakes, so this is a last resort.

I had a quick look through the wiring diagrams and all three brake lights do share a earth connection point (in the interior wiring loom) with the fuel pump/control unit.

Being in the same harness there could be a short.

Both systems also share power through Terminal 30.

So you're decending a hill with your foot on the brake, and it cuts off the engine? I hope not!

Some cars may cut the THROTTLE (or go into limp mode) if you heel/toe, but this implies you are pressing the throttle.

Yeah, it's obviously not that simple!

Damn, wish I could find where I read about it.

So you're decending a hill with your foot on the brake, and it cuts off the engine? I hope not!

Some cars may cut the THROTTLE (or go into limp mode) if you heel/toe, but this implies you are pressing the throttle.

I believe you have to hold the brake and throttle for a period of time (10s) to cut the ENGINE on some cars. If you cut the engine you would lose power steering/brakes, so this is a last resort.

I had a quick look through the wiring diagrams and all three brake lights do share a earth connection point (in the interior wiring loom) with the fuel pump/control unit.

Being in the same harness there could be a short.

Both systems also share power through Terminal 30.

Right, thank you for that.

I have more information now - the hunt is getting exciting. I've followed up my thought about a relay chattering. A short while ago, I got in, switched on the ignition and the stop lights started flickering. I switched off and back on and the flickering started up again and then the stop lights stayed on permanently. Leaving the ignition on, I banged the flat of my hand against the internal fusebox - no effect. I released the bonnet catch, walked round to the front of the car (stop lights still on) opened the bonnet, propped it - this must have taken the best part of a minute - and gave the main fusebox one bang with the flat of my hand. The stop lights went out immediately! The car then started first go. My wife had to go out in the car so that's where the story ends at the moment.

I've often got to this sort of a point with problems and the excitement evaporates the next time you do the experiment and it doesn't work. But let's for the moment think of the glass as half full.

I haven't got a wiring diagram for the Octy II - I've only got the Haynes for the Octy I. Hoever, I think the cubical boxes in the under-bonnet fusebox are relays - am I right? Anyway, tomorrow morning, I'll open up the bonnet, take the top off the fusebox and, if I (subsequently) get 'the stoplight flickers', I'll carefully tap the individual components in the fusebox.

Of course, it is still not clear why the stoplights should affect the ability of the engine to fire but the main job at the moment is to find some way of getting control of the problem.

By the way, I've also emailed the prolem to Shark, attention of Ben, but that was before the latest little clue was discovered.

This *might* just become really enjoyable.

You have PM

In an attempt at vindication I've done a bit of digging, all forum stuff and nothing official, and occasionally contradictory(!) but here we go:

(quite a long post so have spoilered it so save space)

http://community.evo.co.uk/forums/thread.cfm?threadID=39653&startRow=20

Oh and you can't heel and toe and modern VAG - kills the throttle if you press the brakes, until you release both pedals iirc.

Not quite correct - they cut the throttle if both pedals are pressed for more tan 0.25secs or something - you can indeed H&T but it requires more of a stabby throttle approach.

http://www.pistonheads.com/gassing/topic.asp?h=0&f=23&t=812957&mid=0

Obviously on a car like this, when operating the brake and throttle together for heel and toe there is no throttle cut-out, which is unsurprising but nevertheless a relief after hearing horror stories about other VAG products which apparently do this.

http://www.audi-sport.net/vb/detailing/2602-heel-toe.html

As DJ says, you can press the brake pedal first and then use the throttle without it cutting out, but pressing the brake whilst accelerating shuts the throttle down for about 1-1.5s

http://forums.vwvortex.com/showthread.php?1285689

Q: Can you left foot brake the R32?

A: Only for a short time. If you stay on the gas while holding the brake pedal down,

it'll cut the drive by wire throttle completely after about 3 seconds.

Q: Can you heel-toe given the above limitation?

A: Yes. No matter how long you've been on the brakes, you can reach over and blip the throttle. It just won't let you stay on both the gas and the throttle for extended periods of time.

http://www.pistonheads.com/gassing/topic.asp?h=0&f=86&t=787375&i=20&mid=0&nmt=Audi%20A4%20Avant%20crap%20in%20snow

However a bit of a snag in many FWD cars, and I think this applies to all VAG group cars, is that touching the brake pedal cuts off the gas.

and with that, I'll no longer clutter up the thread!

Right, thank you for that.

I have more information now - the hunt is getting exciting. I've followed up my thought about a relay chattering. A short while ago, I got in, switched on the ignition and the stop lights started flickering. I switched off and back on and the flickering started up again and then the stop lights stayed on permanently. Leaving the ignition on, I banged the flat of my hand against the internal fusebox - no effect. I released the bonnet catch, walked round to the front of the car (stop lights still on) opened the bonnet, propped it - this must have taken the best part of a minute - and gave the main fusebox one bang with the flat of my hand. The stop lights went out immediately! The car then started first go. My wife had to go out in the car so that's where the story ends at the moment.

I've often got to this sort of a point with problems and the excitement evaporates the next time you do the experiment and it doesn't work. But let's for the moment think of the glass as half full.

I haven't got a wiring diagram for the Octy II - I've only got the Haynes for the Octy I. Hoever, I think the cubical boxes in the under-bonnet fusebox are relays - am I right? Anyway, tomorrow morning, I'll open up the bonnet, take the top off the fusebox and, if I (subsequently) get 'the stoplight flickers', I'll carefully tap the individual components in the fusebox.

Of course, it is still not clear why the stoplights should affect the ability of the engine to fire but the main job at the moment is to find some way of getting control of the problem.

By the way, I've also emailed the prolem to Shark, attention of Ben, but that was before the latest little clue was discovered.

This *might* just become really enjoyable.

OK - I did the experiment with the lid off the engine compartment fusebox and tapped each of the three relays - the last one I tried ( R4) responded to a light tap by turning off the stop lights. This relay, according to the info, which RWB has very kindly given me, is the one controlling:

Current supply for SIMOS - is this the immobiliser?

Motronic current supply relay - motronic?

Diesel direct injection system relay - not appropriate to a petrol engine.

I'll make sure by repeating the experiment tomorrow.

My thanks to you all.

That relay supplies current to the ECU and associated sensors/switches via the adjacent fuses.