[jderrer]

Hello,

I have been driving a 2000 Golf TDI for about 8 months now. I have done much of the regular maintenance, including changing the timimg belt, tensioners and water pump a couple of months ago. However, I did not adjust the injection pump timing after this job because I did not have the software.

The car runs great and uses about 5.5 l/100km (about 42 mpg). However, the official Transport Canada rating for this year and model of car is about 4.4 l/100km (about 53 mpg) on the highway.
See: http://oee.nrcan.gc.ca/transportation/tools/fuel-consumption-guide/fuel-consumption-guide-results.cfm?year=2000&type=CPC&Mfg=VOLK


I am wondering if adjusting the injection timing could make this much difference to a car with 325,000 km on it. Everything else on the vehicle has been great, and considering that I drive about 100 highway km /day, it would be nice to squeeze a little better mileage out if it.

I have found this forum useful and would appreciate the insight of other users.

 

[chittychittybangbang]

Is it an auto? That lowers mpg. Winter fuel has lower mpg vs. summer fuel. Tires and cargo load also make a big difference in mpg. Injection pump timing shouldn't make that big of a difference in mpg unless it was way off but it does make a difference.

 

[jderrer]

It's a manual transmission. The tire pressure is good, and there is no load in the car on a regular basis except two adult passengers. My driving habits are also good, as I consistently get over 1000 km per tank.

The pumps may now be dispensing winter fuel but I was getting about the same mileage all summer long. I am just wondering if I should be happy with this (already good) mileage, or if it can be improved further to be closer to what the official figures say.

 

[schimmerb]

I started using Power systems fuel additive and that made about a 4% improvement. No noticable change in power.

 

[Bondo]

I have a 01 Jetta TDI that now has 151,000 miles on it and the mileage is slowly decreasing from a normal of 48 mpg to the low 40's to high 30's now. I have ordered the parts to do a belt change and am also going to change the injectors to see if the mileage returns. Tires seem to have an effect and also whether 'the wife' is driving. She is quite the lead foot....

Bondo
Kansas City

 

[JFettig]

I am not sure how the timing effects mileage directly but you will likely have issues with incorrect timing, find someone with VCDS and check it.

You could also try diesel purge(guide on this site in FAQs) to clean the injectors - both you and Bondo.


Jon

 

[mr rooney]

Check out your MAF as this will reduce performance and gas mileage as it wears out.

Just changed mine and car now feels better and give better milage. Car was on 108k miles.

To check if it's working correctly just unplug it and go for a drive. If car feels no different the MAF is past it's best if car feels worse MAF is ok. Simples!