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Discussion Starter #1
There seem to be loads of different plugs to fit to the 1.8ts, does any-one have recommendations on which work the best, also am i likely to see an improvement in fuel economy with their replacement?

The current plugs look well worn but functional and are NGK PMR7A. -

Don't really want to spend a fortune either unless the expensive ones will reduce teh fuel economy a lot - it is always getting 30mpg and friends at work say the 1.8's they had all got 40mpg (though they had less miles on 40K compared to my 103K).

I will try to check valve clearances as well, are there any how to guides or service manual - not sure the easiest way to get into them cheers.
 

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You need:
4x NGK BKR6EKPA
AND
4x NGK PMR7A

They have a 5-year/60000mile life.

Valves are hydraulic, so nothing to "adjust" there...!
 

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Discussion Starter #3
OK kind-of good news on the valves then but no possibility to adjust and improve the fuel economy. I think I'm stuck at 30mpg!! (even 60mph on motorways is 30mpg)

Will look at the plugs.
 

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Make sure the spark plug holes are not full of oil from overspill when filling the engine up as is slowly seeps past the plugs and makes the engine not fire properly.
 

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MPG depends on many things, including state of plugs. Old or dirty plugs will increase fuel consumption, but you should also a drop in performance.

The state of the air-filter (clean? replaced regularly), sensors (lambda, maf, etc), tyre pressures, and most importantly how you drive, and the sort of journey's you do.
 

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Discussion Starter #6
Yup there was oil in the left plug hole, I've cleaned it out but the plug was firing fine despite this.

The air filter was recently replaced, thermostat as well.

Sensors I have no idea but it drives and idles really well, no MIL light and MOT's all say lambda 1.00 at idle.

On a long journey - 2 runs of 180 miles all motorway no jams at 60mph it still gets 30mpg oh forgot 35psi tyres.

For the plugs I'm trying to find some iridiums, found some 14mm replacements not the 10mm's yet, on my motorbikes these give the best performance. Also I spoke to some-one from NGK a while ago about the twin ground plugs (my bike was specced with the same) and he said this was only to improve the life of the plugs not the performance - iriduim should do better (with same or better life).

On a technical matter as well an automotive bod was saying twin spark designs lead to worse performance (despite obvious on-paper advantages) which is probably linked to the 2 flame fronts meeting and promote knock more readily than a single plug. Thing is with a central plug we could just unplug the side plug and end up with a 1 plug design. Anyone done this? Not sure if it will work of the slower burns will reduce performance as the engine is mapped for 2 plugs (faster burns, less ignition advance)
 

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How are you measuring the MPG? Filling tank to brim, taking journey and refilling to brim on return?

If not, you probably won't get close to the true MPG.


MIL light doesn't come on for every fault ... only after it's accumulated a certain number. The only way to find out is to put the car on a diagnostic. That will be Examiner (Alfa/Fiat Dealer and some specialists), AlfaDiag (licensed s/w) or FiatEcuScan (free for a number of uses, and limits the functions)

A lamdba that isn't working 100% could be overfuelling the car ... etc.

Could even be your timing isn't 100%. Not unusual when people try to change cambelts without using proper cam locks.
 

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My 1.8 T/Spark does 37mpg driven like petrol is 135p/litre (i.e. like a tart! :D)

Check your thermostat. The needle should get to just under half way and then stay there.. so around where 76C would be, if you have the early "80C" dash, or where 86C would be if you have the later "90C" dash.

The actual temperature is actually 86C no matter what the dash says.. :D

If the temperature falls into the bottom third of the gauge when you're driving on a clear road, then the 'stat is goosed..

Check the fuelling by cleaning the exhaust tip (wire wool) and then having a look at it after a few days normal driving about. It should be clean (almost no soot should come off onto a clean rag). If it's heavily sooted.. then you have a rich mixture.

Check how you're working out the mpg.. :D Fill the tank to the brim.. drive 75 miles and then refill the tank to the brim. If you can only stuff 9 litres in there.. that's 37mpg... If you can get 11 litres in there, then that's nearer 30 mpg.


Ralf S.
 

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Discussion Starter #9
MPG I calculate brim to brim so should be OK.

Thermostat was replaced a year ago so not that (though now seems to stay at 80deg but I've not measured the fuel economy since it started doing this).

Mixture - I can check with the wire brush but at all my MOT's it says lambda 1 - no faults so if a sensor was faulty would it not show up there?

The car drives nice, revs nicely etc - just average/poor fuel economy.
 
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