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[Jetta Jockey]

Hi Guys, I have lurked a few threads on here and was hoping you guys could give me some pointers.
I bought a non-running(previous owner replaced the headgasket and got the pump out of time) '91 Jetta 1.6 N/A ECO last year and have been driving it ever since after repairing a few things. Clock is now showing 167K+.

I don't seem to be getting the great mileage associated with the diesel, it varies from a best of 38 mpg to a worst of 34mpg, these numbers seem to be dependent on which elevation I am traveling in. I go from 3,000 ft to near sea level on a weekly basis. The car seems to run well, it will do 95 mph down hill.   I'm thinking I might have some intermittent injector spray problems. I've used a fuel additive and have the pump timing set all the way toward the block as this really helped with power/comsumption.

Could my pump be out of whack a few degrees? Maybe the injectors need to be rebuilt? I'd like to see the 45+ mpg, is this a realistic # for a 1.6N/A?
 
Any suggestions, pointers would be appreciated.

[Wingaman]

Normaly with a 1.6NA, you will be around or above 45 MPG (54 MPG Imp.).

Check the timing correctly, air filter and fuel filter !

I'm doing 43 MPG (51MPG Imp.) with my 90 Jetta 1.9TD and i need an alyngment on the front whells.

[farkman]

Welcome Jetta Jockey.

There are a lot of factors that contribute to poor mileage. But there are also a lot of small (or big depending on who you ask) things you can do to to improve your mileage.

First don't drive very fast on the highway, meaning under 100-110 km/h or 60-65 mph. What type of tires do you have? Harder compound tires generally give you better mileage. Also inflate the tires close to the maximum on the sidewall, if you can handle the harsher ride. Next are fluids. I recommend synthetics (ie Amsoil personally) for all fluids. If you don't want to spend the money for synthetics it's up to you, but for some things, like the transmission, the extra cost is more than offset by the gain in fuel economy. I gained 3 mpg by switching to Amsoil S2000 gear oil. You can also regrease the rear wheel bearings with synthetic grease. Service (clean & lubricate) the brakes so that they aren't dragging.

These things should help you get started.

Peter

[Jetta Jockey]

Well, Saturday was a stressed filled afternoon as I finally managed to remove all 4 injectors (2 with considerable difficulty, as they weren't seated properly to the heat shield at some point and the threads were severely carboned up).  :x It took some finagling but I was eventually able to get the injectors out with penetrant and my 1/2" breaker bar. After re-assembly I took it out for a spin that night and it felt like it had more pep and did 103 mph (8 mph more tha before) on my downhill slalom course. :wink: Now, I need to get the pump timing back in a more suitable range and see what kind of mileage I get. :roll:

I was told fuel consumption decreases if driven at a more reasonable speed but I can't drive sub-65 MPH as I would get run down by a transfer truck on the interstate highways here in the US of A. :shock:
Next I prefer a tire that will do well in wet and snowy weather conditions, so hard tires are also not an option. :?
I'll check into the synthetic gear oil and grease for the bearings though.
The brakes have been serviced recently and there are new axles and wheel bearings up front too.
Thanks, Guys!! :!:

[Jetta Jockey]

:? 40 MPG cruizin' @ 75-80+ mph. I suppose that is "okay".

[farkman]

What did you do to get the mileage to increase to 40 mpg? That sounds pretty reasonable for driving at 75-80 mph.

[VWRacer]

40 MPG at 75-80 is outstanding fuel economy! My old 1.5NA would get about 45 MPG at 55-60, but dropped below 40 MPG at 75.

[Otis2]

This looks like another "US mpg v. Imperial mpg confusion thread", which haunts all car forums where both Americans and Canadians post their fuel economy results.

To compare apples with apples, not oranges, it would be easier to talk about the metric "burn rate" of litres per 100 kilometers.  The litre is the same size (if not the same spelling) on both sides of the border.

[VWRacer]

Otis, both Jetta Jockey and I are from the US, so I suspect there is no confusion between us over Imperial vs. Wine Gallons... :lol:

[Cheesetoast]

how often should the fuel filter be changed and is there any particular brand to get for my 93 golf 1.9td?

i get about 750km to a 47L fill, i think that's not great.  I'm swappign the rear drums to disc, i'l be putting in new wheels bearings at the time, but they don't sound worn or anything.

[Jetta Jockey]

What did you do to get the mileage to increase to 40 mpg? That sounds pretty reasonable for driving at 75-80 mph.

 :oops: Fark, I'm by no means a diesel guru nor do I pretend to know much about them PERIOD.... Since I bought the car 2 years ago I have been "workin' with it" to improve the what I was considering "poor" fuel consumption as well as tackling the normal wear & tear items associated with a 13 year old automobile. :x
 
To try to answer your question, nothing in particular.....I've adjusted the pump timing according to some Internet info I found (I'll try to hunt up the link soon, if wanted), used some fuel additive and learned to get out of the pedal when going up steep grades as the momentum falls off.

I was under the impression the 35-38 MPG I was getting, until my most recent foray into diesel mechanics, was not very good. I just assumed everyone getting 45+ MPG was going 75 mph too. :lol:  Some of those miles I drive is stop and go, slower speed stuff, but 90% of it is on the interstate running anywhere between 70 and 85 mph. :wink:
 
As I mentioned earlier, the car wasn't in running order when I acquired it and I didn't know 'diddley' about a diesel besides the most basic understanding. It has been a learning process and I've spent a few hours sifting through message boards and technical links for info. Next week after I get back from the AMA Superbike round @ Road Atlanta I am going to back off the pump timing a smidgen to see If I can get a bit more economy without sacrificing the level of performance (Can that terminology be used to describe a car with 52 HP?:lol:) I have attained. Right now, I'm pleased to no end with the way the car is running, but I still feel compelled to try to get a little bit better mileage.

Thanks for the welcome(s) and comments!!  

[VWRacer]

I was under the impression the 35-38 MPG I was getting, until my most recent foray into diesel mechanics, was not very good. I just assumed everyone getting 45+ MPG was going 75 mph too.  Some of those miles I drive is stop and go, slower speed stuff, but 90% of it is on the interstate running anywhere between 70 and 85 mph.

There is an enormous difference between the fuel economy of late model TDIs and the older, particularly NA IDI diesels. My '02 TDI gets right at 50 MPG (US) cruising at 72-73 on the freeway. (I go up and down I-5 from the SF area to Western Washington regularly.) If I push it up to 76-78 MPH, the economy drops to about 47 MPG.

OTOH, I never came anywhere close to that with my NA Rabbit. It once got 50 MPG when I drove it 700 miles at 50 MPH while following a stuffed-to-the-gills 24' U-Haul truck that was governed to 50 MPH. At the more normal 55-60 MPH it got about 44 MPG. And like I wrote earlier, the one time I ran it as hard as you describe, I got 37 MPG on a several hundred mile trip at 70+ MPH.

No sense not trying, though! Jake (fspGTD) has done repeated dyno tests on his Rabbit, and found that the most power was gotten at (IIRC) at about 1.1mm advance. In a diesel that will translate to the best fuel mileage, as well. You getting good cold air into the intake? Headers and a 2" exhaust will help, though not as much as on a gasser (no overlap on the valves). Skinny tires and high pressures also help. Tall final gear ratio if you are that serious... :wink:

[farkman]

Jetta Jockey

I am certainly no diesel guru either, but I do understand how to get the most of out something. This is why I like synthetic lubricants so much. They cost more in the beginning but in the end, they pay for themselves with better fuel economy and less wear.

Since I put my 2.5" exhaust on my car I have noticed that my mileage has gone up quite a bit. I'll be filling up today after school so I'll know then. My best tank has been 45 mpg US and it looks like this tank will be at least 43 mpg.

Take care.

Peter

[farkman]

This tank came out to 43.3 mpg. This is driving 80% highway/ 20% city, but with all the traffic on the highway (401) it's more like 65% highway/ 35% city.

I should mention that I multiply the total kilometers driven by the percentage increase of circumference from my new tires compared to the stock size tire. Stock tires are 185/60R14 and the tires I have on my car are 185/65R14. The tires are 3.2% larger in circumference compared to stock.

[Jetta Jockey]

If anyone is interested in some photographs from the AMA Motorcycle races....
http://community.webshots.com/album/184756514lPtopv    

My fuel mileage with a strong headwind compliments of TD Frances was 38.5 mpg.  :wink: Okay for me.  :wink:
I'm gonna do the synth. tranny grease when I get a chance.