Newbie, 1.6na jetta( mpg help)

Technical questions and answers concerning all models of VW diesel vehicles.

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Greaser
Glow Plug
Posts: 11
Joined: Mon Feb 04, 2008 12:47 am

Newbie, 1.6na jetta( mpg help)

Post by Greaser »

I just purchased my first vw diesel, I really enjoy it. :) I have read alot about 45-50+mpg but am not seeing that. I live in the mountains in southern WV and only seem to be getting around 35mpg. Car is a 1985 Jetta non turbo with 94k and the 5spd. The previous owner said the injectors had been rebuilt but I noticed one is sweating aroun the body. I run Valvoline full syn 10-30. Also my driving speed is usually around 70.
Any help would be greatly appreciated, I drive about 60 miles one way to where I work so it gets alot of miles put on it. :)
ajt3nc
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Posts: 63
Joined: Thu Feb 12, 2004 12:29 am

Post by ajt3nc »

I used to live near White Sulphur Springs.
I just went to a yard sale and bought a set of 4 new injectors and put them in the 86.
WOW.
NO Smoke and so much quiter.
If you see leakage, replace them.
Informal 3 day tests, about 10% increase in mileage.
Rebuild them with Jack's parts. They will pay for themselves.
86 n/a jetta , 89 td 1.6, 05 passat 2.0 tdi 07 wrx,
coke

Post by coke »

Make sure your tires have 35 psi and the wheels are free turning, no resistance, such as slightly engaged rear brakes, etc.
Vincent Waldon
Turbo Charger
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Joined: Sat Dec 16, 2006 3:05 pm
Location: Edmonton, Alberta, Canada

Re: Newbie, 1.6na jetta( mpg help)

Post by Vincent Waldon »

Greaser wrote:I just purchased my first vw diesel, I really enjoy it. :) I have read alot about 45-50+mpg but am not seeing that. I live in the mountains in southern WV and only seem to be getting around 35mpg. Car is a 1985 Jetta non turbo with 94k and the 5spd. The previous owner said the injectors had been rebuilt but I noticed one is sweating aroun the body. I run Valvoline full syn 10-30. Also my driving speed is usually around 70.
Any help would be greatly appreciated, I drive about 60 miles one way to where I work so it gets alot of miles put on it. :)
Don't forget that you will not get great mileage in the winter... somewhere between 10-15% less at a minimum according to most people's experience.

Winter diesel has less energy, tires/bearings have much more rolling resistance, tranny/engine has more friction, etc etc etc.

Having said that:

- fresh injectors properly set at the right popping pressure
- timing correctly set
- internal pump pressure calibrated (lots of threads here on that subject)
- careful check for tight bearings, dragging brakes, etc
- newer tires with lots of air (older tires have more rolling resistance)
- backing off from 70 mph (the car has more wind resistance at 70 than 60... exponentially)

are things you can do to maximize your mileage.
Vince

Edmonton, Alberta, Canada
2001 silver TDI Jetta Malone Stage 1.5 , 2001 blue TDI Jetta SBIII 216s Malone Stage 3
1970 Bay Window bus

Gone but not forgotten: 1969/1971 Beetles, 1969/1974 Westies, 1979 Rabbit, 1986 TD Jetta, 1992 gas Jetta, 1994 TD Jetta

Here's a small collection of HOW-TOs
Greaser
Glow Plug
Posts: 11
Joined: Mon Feb 04, 2008 12:47 am

Post by Greaser »

thanks for the info. I have already checked everything you have suggested with the exception of the pump pressure, timing and the injectors. The previous owner said the injectors were rebuilt but there is one leaking sligtly around the body. I really appreciate the help though.
520davidb
Glow Plug
Posts: 13
Joined: Wed Aug 01, 2007 1:43 pm

leaking things

Post by 520davidb »

I noticed a slow drop in MPG but I needed a head gasket so I went and replaced the gasket and fuel lines but after the rebuild I still noticed a drop in MPG. I was disappointed in that. I wasn't until I had to fill it with diesel over b99 that I noticed the smell of diesel around the car. Ends up my Injection pump was leaking and I never noticed it until the diesel fill.

A drip anywhere can vastly reduce mileage due to the pressure of the fuel system, which can cause quite a lot of fuel to come out under driving conditions. Mine was practically spraying when it idled.
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