Golf 118 TSI Engine Failures and Service Campaign 24S4

[Corey_R]

While Guy has a lot of experience with VAG engines, it'd be foolish to suggest he has a monopoly on said knowledge...

Well actually - the question I replied to was specifically whether the APR ECU update changes the fuel leaness etc. In that specific instance, I'd take Guy H's word over someone else....

[Kirium]

Well actually - the question I replied to was specifically whether the APR ECU update changes the fuel leaness etc. In that specific instance, I'd take Guy H's word over someone else....

Ah. I follow and concur.

I thought you were referring to the bloke that's pulling engines to bits.

[cme2c]

Interesting. Are there any common threads? like is it always the same cylinder? Which ring lands are failing, that is top ring, second ring, oil ring? Are the valves ok? (apart from damage caused by bits of piston / ring)? How many miles on the engines? that sort of thing.

John

[cme2c]

So it looks like local heating, or a failure in cooling that part of the piston, rather than a general lean mixture. (I'm not saying that's the case, just that that's what it looks like to me). Any commonalities in driving? freeway, city, Eastern creek??

[Greg Roles]

My car has been faultless too... 1.4 twincharger early GT motor.

I think there has been some re-engineering for profit "RFP" on the newer 118 TSI's hence the squeek and other issues.

I think the early GT, GT sport 1.4's are the strongest as they don't squeak and have had no failures as far as I am aware.

The first oxy sensor controls fuel trim to achieve 14-14.7:1 and the second only checks for temperatures and cat efficiency. So you only need the first one to fail for things to go up **** creek as far as the documentation I have on the engine goes.

Remember too that the emphasis is on less and less fuel use, and pushing leaner and leaner mixtures...I wonder if the new 118 touts better fuel economy?

[Paul_OH]

Remember too that the emphasis is on less and less fuel use, and pushing leaner and leaner mixtures...I wonder if the new 118 touts better fuel economy?

It certainly does, by about 1.5lt/100km (combined cycle) - a very significant amount on basically an identical engine with 7 less kW!

Subscribed....

[triode12]

Remember too that the emphasis is on less and less fuel use, and pushing leaner and leaner mixtures...I wonder if the new 118 touts better fuel economy?

Noob question time...what is the cons of too lean a fuel mixture?

[Greg Roles]

Piston damage as discussed for a start! Fuel keeps combustion temps down in petrol cars, and prevents hot areas that have no doubt caused the damage some have found. For example under wide open throttle my old FPV GT ran very very rich, used a stack of fuel, and most of that was an effort to keep the combustion temps down. That's quite normal. It would seem the combination of twin charging, very lean fuel mixtures and Aussie conditions can lead to too much temp in the combustion chamber, and this is the downside of all that.

I'd reckon an aftermarket fuel map, tweaked for Australian conditions, would be highly recommended, along with anything to help keep heat out of the system, CAI, heat wrapping, Polar intercooler ducting, intercooler upgrades / spray, water meth, less restrictive exhaust, lower the thermostat, anything to help the thermal handling of the engine.

[Paul_OH]

A lean mixture produces hotter exhaust gases which could ultimately melt pistons whereas a rich mixture can have the effect of cooling the cylinder/piston but uses more fuel per bang.

oops: didn't see Cogdoc's more comprehensive message before posting.

[seangti]

and to go a step further, too much fuel will hinder performance, too lean and you get the result that has already been discussed. It can be quite a fine line in getting it all to work in harmony and cope with the wide range of fuel types, operating temperature range and elevations.