Low MPG - VW TDI forum and Audi TDI forum

docmor · #1 02-09-2012, 02:08 AM

I have an 2003 Jetta, automatic TDI with 165000 miles on it, I've only had it for about 3 months and checked the MPG on the last 2 tanks of fuel and it is only getting 30 to 31. Ive put on a new timing belt, changed oil with synthetic, new air filter. The car runs good not slugglish with no TDCs. I am going to run some Lucas injector cleaner through it to clean the injectors and pump.
Can anyone steer me on the next steps too get the MPG up or should it be better than 30 MPG. Also I do not have the program to check the timing with but do have access to a Modis but I am not sure if it has the ability to read timing. Does anyone know if this is possable with the Modis?

Seatman · #2 02-09-2012, 02:12 AM

Sticky brakes, underinflated tyres, timing, IQ level, there just a few things that would be good to check. No idea on the modis.

almir · #3 02-09-2012, 10:33 PM

With 165K on the clock, I would check and compare speed and rpms with other members at 40, 60 and 80mph, just to verify that transmission's clutches still have good friction. It is possible that your engine is running at higher than needed rpms to achieve certain speed.

docmor · #4 02-10-2012, 08:02 AM

I have checked with a GPS and it is registering 1.5 miles faster than GPS at 55 mph, I have also checked the breakes for binding, tire presures, wheel bearings, Im not sure about the IQ thingy though

. I am thinking it has to do with the timing because when I did the timing belt, I had the cam position plate in place, the pin in the IP, but the mark on the flywheel was closer the the back side of the inspection hole instead of the front. The car was running great and plenty of power so I locked the crank down and changed the belt. Nothing moved during the belt change and all the marks and cam position and pin in the IP were still in place. From what Ive read so far the timing is mainly set by hand and not by the computer, is that right.

almir · #5 02-10-2012, 09:13 AM

Quote:

Originally Posted by docmor

I have checked with a GPS and it is registering 1.5 miles faster than GPS at 55 mph,

not that type of speed check. For an example: we have the same car, and mine for an example is at 2500 rpm when going 70mph, your might be at 3000 rpm to go 70mph so ask other members who have automatic trans to tell you what rpms they have at 40 60 and 80mph.

docmor · #6 02-10-2012, 03:09 PM

What kind of mileage do you get with your car, and what do you think about the engine crank mark being off that much.

almir · #7 02-10-2012, 05:52 PM

about 38-41 city 50-53 highway Mine is manual with Kumho low rolling resistance tires. 2005 gls tdi (bew)

maycraft19 · #8 02-10-2012, 07:34 PM

I am driving a 2003 jetta wagon tdi, manual tranny, Over 230,000 miles, it has always been very consistent with the mileage. 41-42mpg on a 90 mile per day commute consisting of 70mph + stop and go traffic. Maybe 30 miles highway and 15 miles stop and go.

Will try to remember to check my rpm at varying speeds on monday, will let you know.