Hi there

We have owned a 2002 Fabia Comfort 100 PD TDi since last summer for my wife to use. When we first bought the car, it ran superbly with excellent fuel consumption (of around 55-60mpg). Gradually though the fuel consumption has got worse over time and we are lucky to get near to 50mpg, however the average is only around 44mpg!

I have had several scans with VAG-COM which revealed no issues, however we tested the efficiency of the MAF which was underperforming and was duly replaced (with OE item) - no change reported. Turbo efficiency is fine.

I have given the car a full service including oil and filter (Quantum Platinum), new fuel filter and air filter - still no change! I have read some other threads where people are stating cold temperatures are to blame and also 'winter' diesel can reduce consumption, however I also own a 2001 Octavia Ambiente TDI (90bhp) which consistantly averages around 58-60mpg, and I have actually been noticing improvements of late of around 1-2mpg!

I am wondering whether there is another issue somewhere where it is not showing on VAG-COM? Any ideas/suggestions would be greatly appreciated!!

Thanks

Dan

Well - it will drop over the winter compared to the summer, but I would imagine not that much.

Maybe the fuel filter is overdue a change? Or something else could be causing it to overfuel - flaky MAF perhaps, or flaky coolant temp sensor (thinking coolant is always cold therefore putting more fuel in to keep engine warm)

Well - it will drop over the winter compared to the summer, but I would imagine not that much.

Maybe the fuel filter is overdue a change? Or something else could be causing it to overfuel - flaky MAF perhaps, or flaky coolant temp sensor (thinking coolant is always cold therefore putting more fuel in to keep engine warm)

New genuine MAF fitted (has been tested for efficiency and is working spot on) just before Christmas and new (genuine) fuel filter fitted mid January! Oil change as well with Quantum Platinum two weeks ago!

Could be temp sensor but nothing has been logged on VAG-COM and has been scanned at least 4-5 times of late.

Dan

Flat tyres? Although unlikely to make that much difference?

Repeated accerlerating from dodging all the frigging potholes?

I would try using an injector cleaner - I personally find Millers Diesel Sport 4 (now ECOsport) excellent.

The spray patterns deteriorate when the injectors get caked up - could be you've been using poor fuel or that bio stuff.

I would change the air filter

I would change the air filter

Air filter changed when new MAF fitted. I have given it one dose of Millers Diesel Sport 4 but I will give it an 'overdose' of the stuff - made my Octavia better when I did this.

It seems as though I have done all the necessary stuff but to no avail! Possibly a good long run may sort it out?

Dan

Could it be that when she first drove the car that she drove gently/smoothly as it was a new car to her and now having become familiar with the car she drives a bit more aggressively? I know how easily this can happen. A few years ago I had an elderly Golf that was coming up for cambelt replacement time . Conscious of this fact I drove quite gently not wanting a broken cambelt . After I had the cambelt done I was appalled by the sudden increase in fuel consumption. I was convinced that the cambelt change was responsible for this . Had everything re-checked but nothing found . Finally it dawned on me that I was now confident that the cambelt was not going to break and was driving much more aggressively / normally. It's all in the mind !

Stick some super diesel in there, and some Millers. Give it a proper hard motorway run, and generally hard driving for that tank of fuel, and then see how the next tank of fuel goes.

Oh failing that,

could it be that the intake manifold and EGR areas are all caked up to the hilt with oily soot and gunk?

Stick some super diesel in there, and some Millers. Give it a proper hard motorway run, and generally hard driving for that tank of fuel, and then see how the next tank of fuel goes.

I will give it an OD on Millers. Super diesel seems quite hard to find in my area but will find some! I will check and if necessary clean the EGR and blank off - my Octavia (non-PD) ran better and cleaner with the EGR blanked.

Dan