Originally Posted by
RW1 @ Scirocco Central
The 1.4TSi engine in its Supercharger form ie. 140PS & above was introduced in the Golf 2006 iirc. It's a sleeved cylinder engine, nothing really new there. Manufacturing though has to be to very tight tolerances. Achievement was in power output and lower emission levels. Technology was in the use of a switchable supercharger in addition to the turbocharger to give a fairly constant 2 bar boost from the point the engine starts revving at 1,100 rpm and higher to max rpm. But also to switch off the supercharger boost if driving does not require the torque at normal cruising/driving rpm. (Hence the squeaky clutch noise until it beds in and mechanical clunking from the engine bay)
Until the engine map G4008(Man.)/G4009(DSG) which was introduced in May 2009 (Scirocco MY2010) with the Golf 6 platform electrics (White MFD instead Red MFD), the early maps before this version had the knock sensor input wrongly coded. Since then, although still not perfect, they've had to tweak the maps a little further 2 times and a third time (initial 24S4) after problems started in September 2009 out in Australia with poorer fuel quality available being used by the Mk6 Golf 1.4TSi 160PS owners. This lead eventually to the workshop campaign 24S4 starting out in Australia during May 2010 with maps G5859(M.)/G5860(DSG). A lot of Mk6’s were caught at the Australian docks and updated. The Australian campaign was vigorously enforced with the Golf owners being asked to bring their cars to the dealerships. What has followed is that failures have generally been with Golfs running on the older engine ECU maps and then being updated later or not at all. It has gone generally quiet over there now.
The engine map campaign 24S4 was globally introduced from October 2010 onwards to existing cars in use (problem engines received the new map at misfire problem/repair earlier in the period June – October 2010). I was offered it in June 2010 during its first week of release when mine misfired but as the dealer wasn't talking sense and clutching at straws, I chose to investigate with their permission - see plug gap paragraph below. The factory introduced the revised 24S4 Workshop Campaign engine ECU maps earlier into Scirocco production build, around Wk22/2010, following the Australian experiences.
The 24S4 maps have been further tweaked because of a warm-up problem (which I personally experienced in June 2010). Namely, a misfire at 35'C coolant temperature during warm-up in extremely low humidity air conditions. During early June 2010, a spell of very dry Arctic air settled on the UK and particularly Germany. The forums lit up with posts about misfires on the 1.4 160PS engine during warm-up. Dealers in Germany were changing injectors/coilpacks and getting a no-fix situation. The weather went more humid in July 2010 and the problem went away.
I decided to resolve it a different way as the engine’s problem appeared soon afterwards in a VW bulletin on issue date -12th June 2010 which stated “postpone repairs”. I looked at engine basics and found the plug gaps just a little wider than VW specified. So I bought some spares...... exactly the same! VW specification states 0.80mm to 0.90mm. All the plugs were 0.90 – 0.92mm. So looked up the impact of over gapped plugs used on supercharged engines. Outcome is that the ignition spark gets snuffed out by the airflow into the engine cylinders which leads to cylinder misfiring (obviously!). So I shortened all the gaps to 0.79mm. Wow!... what a different engine. If you think the 1.4TSi engine is good now, try this!!! It totally transforms the engine, not power but no murmuring vibration from what was I thought a reasonably smooth engine and its pick up is now very smooth. Hesitancy and axle tramp banging have gone! And in this year’s dry air like 2010, not a hint of misfiring!
[Subsuently shortened the gap further to 0.74mm (29thou) 19.09.11. See post below 21.09.11. Made some more improvements, so a gap of 0.74mm - 0.79mm (29thou - 31thou) appears to work well]
(NB: You have to be very careful re-gapping fine wire spark plugs that have very small diameter platinum or iridium alloy electrodes. Feeler gauges or wire gauges should be used with gentle care when testing the gap by comparing with the feeler gauge NOT passing the feeler gauge through the gap. Otherwise the central electrode tip will be damaged.)
This spark plug gap change was done to a 2007 Golf 1.4TSi engine at DG Autotech during a visit without the owner aware as part of the problem solving on his engine. He drove out and was soon back to ask what had been changed. So not a one off!
VW have now upgraded the maps to compensate for the 35’C stutter misfire in dry air during warm-up. Those maps were introduced in Dec2010 as G0888(M.)/G8913(DSG) and have become the revised 24S4 installed ECU map standard.
People who, soon after taking delivery, re-mapped their engine ECUs which had those early maps, ie production build prior the MY2010 introduction in May 2009, recognised by the red MFD in the dash (Maps G2*** & G3***) will have avoided the knock sensor issue if the map coding was correctly written using the knock sensor signals as I know one tuner company popular on this forum board has done.
The problem is....... one has to realise that this engine is a real pressure cooker, 160PS out of a 1.4ltr engine !! ..... so, if the engine is damaged by misfiring, it may, despite updating the VW map version or later on in useage re-mapping with a 3rd party, continue to deteriorate over time, albeit as a much lesser pace. An engine can go on quite normally until the damaged part (piston/piston rings) finally do fail and failure is usually catastrophic, good one day, karput the next. Or it starts to turn into a ball of misfires with dash lights on over a number of drives. To reach this, can be thousands of miles after any initial rectification work (updated VW ECU map, new injectors, coil packs etc....) is done. Failure will depend on whether mechanical failure was initiated during the initial misfire problem reported. Failure will also depend on driving style and fuel source used (ie. quality [supermarket v oil company branded; 95RON v 98RON]) - best to feed it well on branded fuel imo, although this is not a rock solid guarantee! One characteristic of looming failure is the oil consumption increasing but you would need to dip the engine oil sump weekly to see this happening and it is not always the case before failure. ...... as said its a real pressure cooker of an engine.
And, not all engines prior to mid 2010 will have problems as there are so many factors to take into account in how the Scirocco is used such as: driven/maintained/fuelled and so on.
But ..... the failures are not coming from the factory built to 24S4 map standard like the MY2011, that I am aware of.
Hence from the above script why on this topic the posts for engines in the Scirocco made prior to mid 2010 (Wk22) are not a useful comparison.
If you don’t know the build, it can be worked out here.
MY2011 engines are not carrying any warning bulletins on this subject that I am aware of.
There was also during a week in 2009 when a batch of faulty coils were made
Along with problem injectors over a longer period in 2009. I have the problematical injectors supposedly...... :shrug:.
The rest about coil packs, injectors, high pressure fuel valves and other parts, are attempts at work by the dealers I believe trying to put right engines with other problems or misfire damage in its early stages.
Obviously there can still be individual engine component failures and all manufacturers have that sort of occurrence.... statistical fact!
The Scirocco is not the only model affected and the problems stem back to the early Golfs from 2006 with this engine. And as said above, the overall % is not a major but is disappointing to the individual owner when it happens. But VW are being reasonable and taking back the engines and giving owners a new one as their warranty covers without much question. Same as other major car manufacturers in the past, here’s a couple......
Rover dealers used to on first service at 10,000 miles whip out the engine of their Rover 200’s around the late 1990’s if, as the technicians were instructed to check for engine noises indicating the cylinder sleeves had come loose. And they did the engine change on the day of the service before the owner came back to collect.
Or all BMW engines used in the Manchester/Liverpool corridor of a certain design around 2002ish iirc where a harden coating chemical (Nikasil cylinder bore linings) was used in cylinder lining protection of aluminium alloy engine blocks. They had to replace the engine with a sleeved version or cast iron block version for all the owners instead. This was because Stanlow Oil Refinery at Ellesmere Port produces fuel that is more sulphurous and caused the cylinder wall's hard coating to be eroded very quickly by the acid formed in combustion.
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