Golf 118 TSI Engine - Revised Spark Plug issued

[Sawed Off]

Thanks, RW1. That was very informative.

[Ozram]

Had our 60,000km service done today and I forgot to ask about the revised plugs. When I checked the itemised invoice I was pleasantly surprised to see they had used the new part number. I'm sure its not my imagination but the engine *does* feel a lot smoother.

[RW1]

Good, you'll find different in the way the gears are used by the DSG on certain roads to previous.

Some more info.....

The revised NGK plug 03C 905 601A VW have introduced on the 1.4TSi 160PS is NGK PZFR6R8EG. "8" refers to the plug gap... 0.8mm. Link to description

The safe way of gapping these wire tip electrode plugs. Note the comment about breaking the tip if you are rough with them.

[glennbot]

For a long time now my 118TSI has has a small misfire at idle when warm. I have mentioned this several times when getting my car serviced and repaired but other than "we upgraded the software that should fix it" response, the problem still persists.

Basically the idle isn't smooth - I can hear a slight dip in the idle about every 5-10 seconds.

Another strange thing is normally the car idles at about 700-800 rpm but last week I pulled up at the lights and noticed the engine stayed at 1,000rpm.

I was wondering if any one else can confirm if this is 'Normal'?

[RosscoMK3]

Another strange thing is normally the car idles at about 700-800 rpm but last week I pulled up at the lights and noticed the engine stayed at 1,000rpm.

I was wondering if any one else can confirm if this is 'Normal'?

Was the AC running?

[Sentinel]

The safe way of gapping these wire tip electrode plugs. Note the comment about breaking the tip if you are rough with them.

That's good to know ... but it seems it would only work with the conventional one-pronged spark plug. Is there an equivalent for the three-pronged spark plugs used in the 118TSI?

That NGK multitool tool shown in the video looks like it might be a possibility - but they don't show how to use it.

I'm having rough idling issues, even after getting new pistons, rings and injectors. The spark plugs are still original, though, and I think they might need to be regapped.

Between the coil pulling, special grease, and the platinum tips, I think maybe I should ask a professional VW tuning workshop to do it. Is that one of the services they offer?

[RW1]

That's good to know ... but it seems it would only work with the conventional one-pronged spark plug. Is there an equivalent for the three-pronged spark plugs used in the 118TSI?

Are you sure this type is fitted?..... odd???

[Sentinel]

Are you sure this type is fitted?..... odd???

No, I'm not.

When I went to talk to my local mechanic (who is not a VW specialist) about spark plug gaps, he showed me a three-pronged platinum plug as an example of the type used in the 118 TSI.

He was mainly talking about how easy it is to damage the tip, but I assumed the VW had three prongs as well.
He might have just grabbed the first platinum plug he saw. I don't know what the actual 118TSI plug looks like.

[RW1]

OK, this is what the old (top left) and new replacement (bottom right) look like. Same apart from the gap is reduced from 0.90mm +/-0.05mm variance to 0.80mm. VW's gap setting is specified as 0.80mm to 0.90mm which in my opinion and useage is too wide.



I replaced mine at 17,127 miles (27,563Km) and three years running as despite cleaning, the plugs had a little misfire in the last 3 months of use noticable at idle, particularly when cold. Shy of 4 years and 60,000Km specified for normal operation/servicing. This what they looked like when they came out.....



The engine runs within Severe Operating Conditions as it does only two 6 mile trips a day generally in urban traffic, both with cold start and the oil rarely exceeds 70'C. The electrode tips were OK but the insulators just not clean.

The gap 0.70mm had been set for the last 6 months of the plug's use, previous to that 0.75mm for 9 months and 0.80mm for 12 months earlier. As originally factory fit supplied, the gaps had been 0.92mm.

Interestingly a Scirocco just two weeks ahead of mine in production had the same plugs gapped at 0.85mm as original fit when I measured them. That varience has been part of VW's 118Kw misfire problems, hence the spark plug revision in 2011 as per this topic.

0.70mm removed all murmuring misfire [no little kicks mostly felt when idling] and no dash indications for the engine. Made a lot of difference to the the way the 7 speed DSG operates as well . Gear change points lowered and clutch switch overs not being felt (seamless).

Change of 4 different petrol brands in the UK over the 17,000 miles did not make any difference to the insulator fouling over time, even with cleaning.

New 03C 905 601A with 0.70mm gap made a continued difference since fitting 2 months ago.

[Sentinel]

Thank you so much for the photos and all the detailed information! Now I have something more to go on.

I've decided to ask a professional to regap my existing plugs, or to install the new ones. I don't have the tools - and frankly, when I used to do all my own mechanical work on a Mini Cooper S motor many years ago, I managed to get a lot of it wrong. The TSI engine is way more complex than that!

Even though it's just come back from a full piston and injector replacement, my 118TSI still idles rough when warm. RPM randomly varies between 600 and 800. Prior to reaching 38,000km, the engine would idle at exactly a little above 700, and never vary at all.

I plan to contact a specialist VW tuner, and ask for my original plugs, from the 2010-built engine to be regapped to 0.7mm. Do you think this is a good idea? Or should I just ask for the new plug version to be fitted?

Again, thank you for all your effort in explaining the issues.