Tdi 100/tdi 130 mpg

[caldirun]

I have both a 100bhp tdi and a 130 tdi, the 100 returns 50mpg at best and the 130 has averaged 60mpg over the last 2600 miles.
I am in the process of discovering the reason for the 20% better frugality of the 130.
I have fitted a new thermostat (now opens at 89.1 as opposed to 78.6) and a new coolant temp sensor, no change in mpg.
I swapped the manifold airflow sensors, no change.
I fitted a new manifold pressure sensor (they are incompatible as the 130 is an 05 and the 100 is an 02 car) no result, well the mpg did not go up but the car went into limp mode at 3000rpm, I refitted the old one and no problems (except the mpg discrepancy). I have sent a message to Ebay seller su_nioj informing him that his product is either the wrong part (VW part number had been removed!) or it is a faulty part he sent me.
I have checked the brakes for dragging, no problems.
Anyone have suggestions as how to trouble shoot this problem?

[zollaf]

is the 130 a standard factory map ? are they both driven at the same speeds. the lower power one has to work harder to keep up ?

[caldirun]

is the 130 a standard factory map ? are they both driven at the same speeds. the lower power one has to work harder to keep up ?

As regards the map, who knows? how can you tell?
The cars were both driven by me at different times but under the same conditions, a lower power car would have to do just as much work as a higher power car, no more no less (in fact the 130 has 200kg of tools in the boot so has to work harder under acceleration and uphill.

[martin1810]

I would be wonderng why the pd 130 gives a mpg of 60mpg average. That seems beyond belief to me. I know people claim great mpg for these cars but I have never seen an average value above 50 mpg. I guess I just have a heavy right foot.

[caldirun]

I would be wonderng why the pd 130 gives a mpg of 60mpg average. That seems beyond belief to me. I know people claim great mpg for these cars but I have never seen an average value above 50 mpg. I guess I just have a heavy right foot.

Its not a foot problem, its a wallet problem, I get the same price for my work miles as I did in 2001 when the diesel was 80 pence/litre, driving intelligently (emphasis on gently) is a way of keeping the wolf from the door!

[scotty33]

The cars were both driven by me at different times but under the same conditions,

Do you by any chance drive the 100 shorter distances? e.g I changed my place of work and lost 5mpg because the trip is 9 miles instead of 12. Different times of day can make a huge difference, if I make my work commute at 7.35 am I get 55mpg if I'm careful. I take the same route at 8.15 in the evening on mondays and have hit over 80mpg with VERY careful driving, but regularly top 60 without really trying (always 45 or less mpg going back home, which is climbing for the last part!)

I've topped 60mpg average, but it took a 270mile round trip to achieve it!

All I can suggest is try the Tdi Health check on Martin's site, it may throw up something? Maybe check the cam timing? Something I still need to do on my variant which is consistently lower mpg than the saloon..

[bk.bas99]

I have had my 130 estate for 2 years now and over that time have averaged 43 mpg with a combination of short runs, motorways cruising and trips into/across london, av 15K miles a year (I never reset the 'overall' trip computer). I hear of all this mythical 50+mpg stuff but only time I have got that is on a long A-road run cruising around 70 mph. Anything above 70MPH and the MPG tails off RAPIDLY!

[scotty33]

I have had my 130 estate for 2 years now and over that time have averaged 43 mpg with a combination of short runs, motorways cruising and trips into/across london, av 15K miles a year (I never reset the 'overall' trip computer). I hear of all this mythical 50+mpg stuff but only time I have got that is on a long A-road run cruising around 70 mph. Anything above 70MPH and the MPG tails off RAPIDLY!

Some Tdi's seem to be able to be very good on fuel, others less so. You either accept it, or find out why? :

VCDS AND PD TDI ENGINE HEALTH CHECK - PASSAT


Have you ever made a conscious effort to get better mpg, do you ever use the instantaneous mpg and mpg1 readings, to see how things change if you try driving differently?