hello everyone,

i have filled up my 1.9 tdi slx octavia with £40 of diesel once the red light came on and now red light came back on and ive only covered 289 miles. It does show average fuelconsumption of 49mpg??

engine does run ok, no noticable problems and no faults recordered

just out of intrest, how many miles would you cover with £40 of diesel worth in your tank, but sensibly driving?????

Best way to calculate fuel consumption is by brim filling the tank, running the car and then brim filling it again and looking at the mileage in between.

Assuming that you have used around 40 litres of fuel, I would have expected about 400 miles. Have you been doing a lot of town driving?

If not I would probably look at the temperature sender as when these fail it tends to make the ECU think that the engine is cold all the time and so use more fuel.

hi exaudisi,

no it wasnt the town driving, it was mainly the dual carrigeway 60-70 mph. I had thort about G60 temperature sensor, i have scoped the warming up process and the graph does appear to be the same as sample one on VAG 5052.

Never owned skoda and never worked on one, but it appears that layout of whole car to be very simmilar to SEAT toledo/bora?

any other sugesstions on high fuel consumption???

I had this problem on a MK1 TDi before and it was the MAF sensor.

MAF SENSOR???

but my engine runs ok, and power is present?

how many miles did you get out of your octavia mk1???

Mass Air Flow sensor.

It senses how much air is entering the engine so that it can inject the appropriate amount of fuel in. If this is not working properly then it may be injecting more fuel than it needs.

Is it smoking more than normal?

Phil

289 miles on 40l in 70mph dualcabbageway cruising; that's bad. Mine (same car, manual box bar bigger tyres which should make consumption worse) will do 500 miles on 40l in those conditions.

The mechanicals will be the same as a Vw era Toledo, or a Bora, with the same engine.

hello chaps,

no it doesnt smoke, but i have noticed that if i pull over and jump out of car leaving engine running there is fairly strong diesel smoke???

Suggests either MAF or temp sender to me if it smells overly dieselly.

how many miles did you get out of your octavia mk1???

Just over 440 miles to a tank full.But it was the later 100PD engine (AXR).

ahhh,

will need to have close look, my engine code is AHF. I have filled it up when low warning light came on and 290 miles for £40 of diesel. I must admit there was more space for fuel in the tank and i belive with full tank wich is probably £58 it will do around 400??

I will give you update shortly chaps,

will have to scope G60 once more and will have to check MAF sensor.

for now thanks for all your suggestions

Mine is an ASV TDI 110 and on my trips commuting to work (about 10 miles each way. mostly dual carraige way, but frequently sitting in traffic) I average around 500 miles from brim filled to light on which is around £45 - £50 and averages around 45 mpg I think.

that is not bad, i belive ASV is a pumpduce engine and it will be diffrent from mine. I belive my one is AHF 115 bhp, but still fuel consumption should be lot better???

ASV 110 is non PD.They are a good engine producing good mpg figures:thumbup:

or they are not?

ahh

i thort they were???

This topic has been done to death but since you mention it my TDi110 estate averages about 42mpg overall. I can get 50+mpg on a longer run, and have even seen 60mpg average on certain runs. I do put it down to the way it's driven and the type of journeys it's used for. I've scanned mine several times with VCDS, and it runs very well. It doesn't smoke which would otherwise indicate over-fuelling, so I'm not convinced there's too much wrong with it. Other owners do claim to average 50-55mpg consistently, but mine never does.

I'd say I get 450 miles to a full tank on average......

Nine of us bought TDi110 hatchbacks (1999 1.9l SLX AHF) and all of us get 60ish at a constant 60mph. Interestingly one mate has the same car, but a year newer (2000) and he didn't get the same mpg until had it remapped - now he does.

We almost always get 50+ average, but as Railroad says it it dependent on the journeys it is used for.

We all tend to do the same journey to work. A stretch of A road with 40 (no overtaking), 50 and 60MPH (not worth trying to overtake). A longish stretch of dual carriageway, followed by dual carriageway with roundabouts every 500 yards. No traffic jams.

This topic has been done to death but since you mention it my TDi110 estate averages about 42mpg overall. I can get 50+mpg on a longer run, and have even seen 60mpg average on certain runs. I do put it down to the way it's driven and the type of journeys it's used for. I've scanned mine several times with VCDS, and it runs very well. It doesn't smoke which would otherwise indicate over-fuelling, so I'm not convinced there's too much wrong with it. Other owners do claim to average 50-55mpg consistently, but mine never does.

I'd say I get 450 miles to a full tank on average......

On the same type of vehicle I get almost the same results.

My average over 60,000 miles is 45.14 mpg; my best average over 5 consecutive tanks full is 47.89 (mostly long journeys) and my worst 42.99 (cold winter and short trips).

Brim to brim is always 450 to 500 miles, filling up when it says I have 30 miles left.

Computer display of long term fuel consumption is 48 to 55 mpg.

I think it's worth pointing out that things like the MAF and coolant temp sensor can give readings that are wrong but still within the right range and hence don't log a fault. With the CTS you get implausible signal errors, where the sensor has presumably said somethin daft like it is -100 degrees outside which is blatantly wrong, but if it says it's 10 degrees instead of 20 then the ECU isn't necesssarily going to log a fault.

It may be worth getting the injection pump timing checked as well, when was the cam belt last done and how long have you had the poor consumption?

hi guys, thanks for all you input.

i havent had car for too long, say about 7weeks. If im extremly carefull and drive 50/55 mph on long stretch with no overtaking trip computer does show 58 miles per galon, but if i drive normaly around 65/70 mph average goes to 44 miles per galon. I thiks this is very poor. I have had a close look at it today, couldnt see anything obvious.

I have serviced car before i started driving, all parts used were original from TPS.

i didnt get chance to have look at fuel pump timing, but hopefully in two weeks time i will get cam belt, tensioner, roller, and water pump changed and will see if timing was right?????.

I do agree with TRUNDLENUT about intermitant fault with coolant tem sensor, but i have scoped it today for the 3rd time from stone cold and its graph pattern was identical to sample one on vas5051.

and yes ASV is normal tdi, this was stupid statment from me!! i was referring to ASZ engine being pumpduce..douh meee!

with the older grey CTS the problem was when the engine is warm rather than cold, I think the sensor reports the temp as colder than it is and so you get high revs at idle and on start up.

yeah thats right, they normally get stuck in hot position and it is very hard to start engine when cold as you get weak mixture 1 and 2 condensation in inlet manifold causes to dilute injected fuel, and it is very hard for fuel to stay in atomised condition. Once they warm up they are ok.

this is the theory, but they can also get stuck in cold position and cause timing and injected pattern to be out of line.....etc

well see, on 3 rd tank so far and see what milage i get out of it this time

/\ That's a very interesting theory, but diesel engines inject fuel directly into the combustion chamber, not into the inlet manfold or ports.

Yes you are right. Above statment was related to petrol combusted engine, theory behind g60 sensor on normal convencional engine, however timing adjusment on this diesel engine is done through needle lift sensor on the fuel injector etc.....