94 TD Fuel Economy

[Fingaluna]

Hi All, first post, please be kind...

I have a 1994 TD Jetta which I really like.

Here's what I don't like: Natural Resources Canadahttp://oee.nrcan.gc.ca/transportation/tools/fuelratings/ratings-search.cfm?attr=8 lists my Jetta as being able to acheive 51mpg/5.5L per 100km. This would mean on a 55L fill, I should be able to get 1000km, no?

Well, far from it. The best I can get is around 700km on a 55L fill. I know you can NEVER get what the ratings say, but shouldn't I be doing a bit better?

Here are some notes:

I drive around 110kmph and don't floor it on acceleration. I don't drive like grandad either.
Car has 250,000km on it.
Rebuilt motor has 26,000km on it.
Car starts well and runs SUPER SMOOTH - a real joy to drive.
Rebuild included fuel pump.
Fuel filter recently changed.
Synthetic oil used since rebuild.
Some smoke when cold, but not when warm - unless I drop the hammer.
Using 100% Biodiesel which I know gives roughly a 5% penalty in fuel economy. It's canola Biodiesel.
A non-VW guy (AAA in Columbus last year) said that the injectors weren't balanced and this could be a problem. Is this true?
Timing has not been advanced. Local VW guy says it's bad for the turbo.
Tires at 40psi.
Wheels slightly out of alignment. Not too bad, but a bit.
New air filter 5000km ago.
Compression not known.
Odometer is a little off, it reports 3% low, so 700km is actually closer to 720km.
I have AC but don't use it.

Now for the questions:
Am I on the low side for fuel economy?
What do other folks with the TD get?
I know a guy with a 97 TD (not TDi) who says he gets 900 in summer and 850 in winter. Is this the same motor?
What can I do to get this improved? I don't mind spending a little money, not tons, but some is OK.
Do I need to slow down? I have tried driving at 100kmph but it seems to make no difference.
Is there anyone who works at a shop in the Guelph/Acton/Milton areas of Ontario who can help out...?

Thanks folks!

[burn_your_money]

Welcome to the forums

It is possible to get better then the posted mileage, I do sometimes.

Your engine's fuel efficiency peaks around 3000 rpm (perhaps a bit different on the 1.9 vs 1.6) so at 110 you should be a bit below 3000.

You should advance your timing to 1.00mm, your turbo will be fine.
Unbalanced injectors will certainly yeild poor results in mileage and preformance, I'd get those rebuilt/calibrated as a first order of business.
Even having the AC installed uses up a bit of power, not a whole lot though.

In my 92 1.6TD I get anywhere from 700 (driving like a jackass) to 1000km (90% highway, 110 km/h) per 45 liters. My car is a fair bit lighter then yours though.

The 97 and your 94 is essencially the same engine, although the 97 will have a different pump.

Where do you get your biodiesel?

[Fingaluna]

Hi Tyler,

Thanks for the reply! I will have a look at getting my injectors looked at as soon as the new paintjob is done  

I figured that having the AC installed would detract a minor amount, all the extra friction et al, even when the compressor's not running...

What's the feeling out there, buy new injectors or get the old ones rebuilt? Is there a good way to go here?

I get my Biodiesel from Truck Town Terminal in Milton Ontario, near hwy 25 & 401. I also have a few other spots in the USA that I get it (Columbus, Flint, Cleveland, etc.) as I drive down there quite a bit. I buy it at 100% and blend it myself to 50% for winter. In spring/summer/fall I use it straight.

Cheers,
Matt

[Doug]

Your poor mileage may be the result of a poor rebuild. Poorly fitted valves and leaking seats can only be detected by a compression test. There are a lot of hacks out there that claim to know what they are doing but turn out lousy work. Using synthetic oil after a rebuild will often result in the rings (I am assuming that they were replaced) not seating properly. Change out the synthetic and put a cheap diesel rated oil in the motor for at least 10,000 km and run it hard. With modern oils especially synthetic, you will not see oil burning out the exhaust pipe. Check the pipe for a black soft almost tarry deposit, though not shiny. Checking the pump timing is a good idea as well. Why was it rebuilt at such a low mileage? Was this done to cover up some damage due to neglect or abuse. Have also heard that some models in that year range had premature camshaft wear due to poor metallurgy. That could also cause some mileage issues.

[Jetta Fan]

Hi Matt.

I have a 97 Jetta with the 1.9 TD. Last summer I was getting around 52mpg with it, hit 54 on one tank, but I prefer to figure out my mileage over several tanks. It dropped in the winter and is on the rise again, but I am also driving the car harder. I usually run 110kmph to 125kmph on the highway, and usually have it to the floor pulling away. I've been shifting at between 3600rpm and 4000rpm. The last few tanks have given me about 49mpg.

And just for reference, at 110 I'm turning 2800rpm and at 120 I'm a hair over 3000rpm.

[burn_your_money]

Have the injectors rebuilt at a repuatable shop, some "new/rebuilt" ones aren't balanced very well and need to be pop tested anyways.

I was aking about the biodiesel because there alot of people that don't understand the difference between Bio and WVO, which has a huge effect on mileage, especially if you run pure WVO, with no preheaters or flushes etc.

[Fingaluna]

Jetta Fan - Thanks for the good info - that sounds like a good target, I hope I can get there!

Doug - Yeah, I thought of the crappy rebuild possibility. Will getting a compression test done give me the goods or are there other indications? As I said, the car runs fantastically.

Tyler - I don't burn any straight veggie, I just haven't had the time to set up the system. Can't really see myself doing it either, when I have good quality 100% BD right down the road from me. In terms of the injectors, getting them rebuilt sounds like a good idea. Can anyone suggest a reputable shop in the Guelph/Milton/Acton area? My local shop is Arno's VW in Georgetown/Glen Williams, and they seem great (other than not wanting to advance my timing...), but does anyone else have any suggestions?

Thanks,
Matt

[burn_your_money]

Giles is the guy to talk to. He will do it right the first time. Check the Vendors section. Make sure it is his new shop though. He is in Markham IIRC

I wish I had bio available up here.