I know this has been covered before but i think this is different.

Car is mechanically standard, tyre pressures ok, services using genuine parts 1000miles ago.

Maf sensor has been changed by me on tuesday fr a bosch unit.

And still i struggle to get 40mpg, managed to get 45mpg on the motorway yesterday on a 40mile journey, standard i read the car should get at least 60mpg on motorway and 45mpg urban.

The car came with a decat but i changed it, could that have clogged up my egr? The car has no faults, i have vag com can i run driving logs with this? I dont have any boost leaks, get small amounts of smoke on hard acceralation!

Its doing my nut it!

Help!

Try changing the thermostat

Whycould that be causing it out of interest?

dodgy thermostat will fool the ecu into thinking the engine is colder than it is and therefore will continue to over fuel.

How easy are they to change? Anyway to check the thermostat? And how much are they new?

What sort of mpg should I be seeing around town?

Tech spec on autotrader says 46mpg urban, 54mpg combined and 62mpg motorway

Mine doesn't seem overly good on fuel either, even when I drive with that in mind i only seem to about 41mpg.

loads on ebay from £4-13 like this...http://www.ebay.co.uk/itm/QH-THERMOSTAT-KIT-RC493567P-TO-FIT-SKODA-FABIA-1-9-99-OE-QUALITY-/110924113450?pt=UK_CarsParts_Vehicles_CarParts_SM&fits=Model%3AFabia|Cars%20Type%3A1.9%20TDI%20RS&hash=item19d397a62a&_uhb=1#ht_1475wt_1012

God knows how or where to fit it!

Dan

Wouldnt trust something from ebay, would be tps or something!

Yes get one from a reputable parts place. I believe they can be checked by placing it in a pan on a oven hob full of water. Put a glass thermometer in too. it should open fully before the water boils. If it is open before 70 degrees or you can blow any air through it when it is cold then it needs replacing.

Where are they in the engine?

What engine and year? I will check the Haynes manual.

Erm, september 2005 so a 55 plate, dont know what engine!

Diesel engines looks like it is located in the plastic housing where the water pipe returns to the bottom of the radiator. Looks like about four pipes go in to it. Drain the system and remove the large pipe and then the cover by removing the two screws either side of the pipe. It is in there. Remember to refill with the official G12 or G13 coolant.

hi there,

i can get at a steady 70mph about 60-62 mpg, on a good run, then on the a-roads average about 50-56 mpg at 50-60mph, is this good.

Well aye, anything done to it?

im in the same boat. just been living with the 40mpg granny driving as i dont want to start replacing alot of parts to eliminate things. Keep us updated with your findings

Oh and is not more the coolant temperature sensor that could be the issue?

i have no idea thats why im asking haha! im out of ideas after the maf sensor and clogged egr valve!

I thought the coolant temperature sensor was for the gauage only. I dont think the car adjusts fuel based on engine temperature, only on air flow and air temperature. Replacing the MAF sorts issues with reading the air flow.

The coolant guage on the dash is not directly proportional.

For example:

http://www.electricsubaru.com/tempGauge/gaugeGraph.png

That is why you can not tell if the thermostate is broken using the guage. It is basically exception reporting. In other words it only tells you when there is a problem so that you dont have to check loads of guages for all the things the car measures.