Author Topic: causes of low mpg on 1.9td  (Read 8172 times)

January 28, 2011, 10:13:50 am

xxkoadyxx

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causes of low mpg on 1.9td
« on: January 28, 2011, 10:13:50 am »
I have a 93 1.9td with 376'000kms on it, it seems to be getting poor fuel millage as im only getting about 500km-maybe 600 kms.. this is with super easy driving..it has a new air filter on it as well that i put on before winter as i use a cone one in the summer..idk what else could be the problem.....anyone have any ideas??

THANKS
Koady A
93 vw Golf 1.9TD soon to be stage 3 malone TDi (project)
2003 VW 1.8T Passat (daily)

Reply #1January 28, 2011, 10:20:26 am

R.O.R-2.0

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Re: causes of low mpg on 1.9td
« Reply #1 on: January 28, 2011, 10:20:26 am »
im sorry im a stupid american..

whats that in MPG?

have your pump and injectors ever been serviced?
92 Jetta GLI - Black, 1.6D w/ GT2056V turbo..
86 GTI - 4 Door, Med Twilight Gray, Tow Machine..
86 Audi Coupe GT - Tornado Red, All Stock.. WRECKED.
89 Toyota 4Runner - Dark Grey Metallic, LIFTED!

Turbo: exhaust gasses go into the turbocharger and spin it, witchcraft happens and you go faster.

Reply #2January 28, 2011, 10:25:05 am

Vincent Waldon

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Re: causes of low mpg on 1.9td
« Reply #2 on: January 28, 2011, 10:25:05 am »
If that's winter city driving in a cold part of Canada that's not actually too bad... winter diesel has 10% less energy than summer diesel and stiff oil/tires/bearings/snow can easily drop your winter another 10%.  A 15-20% drop in fuel economy over the winter is very typical of diesel-engined cars.
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

Reply #3January 28, 2011, 10:30:20 am

xxkoadyxx

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Re: causes of low mpg on 1.9td
« Reply #3 on: January 28, 2011, 10:30:20 am »
alright so about 21-25 mpg if it has a 14.5gallon tank.. im not sure as that was for a 2.0..couldn't find specs on  a 1.9td fuel tank..
the injectors or pump has not been sense i owned it..2 years..Also i wouldn't get  any higher then 600 in the summer, no matter how hard i tried.
93 vw Golf 1.9TD soon to be stage 3 malone TDi (project)
2003 VW 1.8T Passat (daily)

Reply #4January 28, 2011, 10:32:09 am

R.O.R-2.0

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Re: causes of low mpg on 1.9td
« Reply #4 on: January 28, 2011, 10:32:09 am »
!!! omg.. thats terrible..

i wonder if the advance mechanism in your pump is stuck?

or if your injectors are soo crappy they barely atomize fuel?
92 Jetta GLI - Black, 1.6D w/ GT2056V turbo..
86 GTI - 4 Door, Med Twilight Gray, Tow Machine..
86 Audi Coupe GT - Tornado Red, All Stock.. WRECKED.
89 Toyota 4Runner - Dark Grey Metallic, LIFTED!

Turbo: exhaust gasses go into the turbocharger and spin it, witchcraft happens and you go faster.

Reply #5January 28, 2011, 10:35:18 am

xxkoadyxx

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Re: causes of low mpg on 1.9td
« Reply #5 on: January 28, 2011, 10:35:18 am »
im not sure, the rpm doesn't change when i pull the cold start out.idk if its suppose to or not, i know it does on my bros 1.6td. how would i check the injectors? what does it mean to atomize the fuel? would that reflect poor mileage?
93 vw Golf 1.9TD soon to be stage 3 malone TDi (project)
2003 VW 1.8T Passat (daily)

Reply #6January 28, 2011, 10:49:36 am

R.O.R-2.0

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Re: causes of low mpg on 1.9td
« Reply #6 on: January 28, 2011, 10:49:36 am »
is a solid stream of fuel going to burn easier?

or tiny little fuel droplets?

injectors spray a super fine mist of fuel when they are operating correctly.

if they have clogged nozzles, or broken nozzle tips, they shoot a stream, or just half ways atomize the fuel..

and your idle should definitely increase when you pull the cold start knob..
92 Jetta GLI - Black, 1.6D w/ GT2056V turbo..
86 GTI - 4 Door, Med Twilight Gray, Tow Machine..
86 Audi Coupe GT - Tornado Red, All Stock.. WRECKED.
89 Toyota 4Runner - Dark Grey Metallic, LIFTED!

Turbo: exhaust gasses go into the turbocharger and spin it, witchcraft happens and you go faster.

Reply #7January 28, 2011, 10:59:01 am

xxkoadyxx

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Re: causes of low mpg on 1.9td
« Reply #7 on: January 28, 2011, 10:59:01 am »
so how would i get my injectors checked? go to a diesel mechanic and get them to test them? what would i have to do about the cold start?
93 vw Golf 1.9TD soon to be stage 3 malone TDi (project)
2003 VW 1.8T Passat (daily)

Reply #8January 28, 2011, 11:01:19 am

coke

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Re: causes of low mpg on 1.9td
« Reply #8 on: January 28, 2011, 11:01:19 am »
Someone you know who has a pop tester can test them for pop pressure and spray pattern. Alternatively, you can go to any diesel service center that can test bosch fuel injectors.

Reply #9January 28, 2011, 11:02:14 am

R.O.R-2.0

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Re: causes of low mpg on 1.9td
« Reply #9 on: January 28, 2011, 11:02:14 am »
anyone with a pop tester could test them..

and as for the cold start, it may just need an adjustment on the rod that goes from the cold start lever to the pump top..

or your pump could be so far worn out that it cant build any internal pressure, and cant move the advance piston.

even then, it should still change engine sound slightly when you pull the CS cable, even if it doesnt kick it into high idle..

does it rattle any more when you pull the cable?
92 Jetta GLI - Black, 1.6D w/ GT2056V turbo..
86 GTI - 4 Door, Med Twilight Gray, Tow Machine..
86 Audi Coupe GT - Tornado Red, All Stock.. WRECKED.
89 Toyota 4Runner - Dark Grey Metallic, LIFTED!

Turbo: exhaust gasses go into the turbocharger and spin it, witchcraft happens and you go faster.

Reply #10January 28, 2011, 11:08:23 am

xxkoadyxx

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Re: causes of low mpg on 1.9td
« Reply #10 on: January 28, 2011, 11:08:23 am »
alright ill look around for someone with a pop tester.. well when i pull the cold start out it does start the car a lot better, just the rpm doesn't seem to change when i put it back in.
93 vw Golf 1.9TD soon to be stage 3 malone TDi (project)
2003 VW 1.8T Passat (daily)

Reply #11January 28, 2011, 11:12:50 am

Vincent Waldon

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Re: causes of low mpg on 1.9td
« Reply #11 on: January 28, 2011, 11:12:50 am »
well when i pull the cold start out it does start the car a lot better, just the rpm doesn't seem to change when i put it back in.

If the car starts noticeably better with the cold start out our cold start lever is probably working just fine then... some pumps have a fast-idle feature but lots don't.  Or you may have one but it's not adjusted properly.
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

Reply #12January 28, 2011, 11:28:17 am

theman53

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Re: causes of low mpg on 1.9td
« Reply #12 on: January 28, 2011, 11:28:17 am »
My car didn't pull at all. I had to do all new front end parts and have it aligned. THis is my first tank through since the alignment, but I bet I will get 3mpg better. Alignment makes a big deal.

Reply #13January 28, 2011, 07:55:15 pm

xxkoadyxx

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Re: causes of low mpg on 1.9td
« Reply #13 on: January 28, 2011, 07:55:15 pm »
right now im at 1/4 tank and only got 435kms..i dont wanna do allignment as im getting coils in future and dont wanna do it twice :p.my car has 11psi boost.
93 vw Golf 1.9TD soon to be stage 3 malone TDi (project)
2003 VW 1.8T Passat (daily)

Reply #14January 28, 2011, 08:01:53 pm

catlin_cava

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Re: causes of low mpg on 1.9td
« Reply #14 on: January 28, 2011, 08:01:53 pm »
Koady, its the winter, my TDI went from 1200 to 700 to 800 a tank, The City is also WAY down, about 300 to 500kms at the most.
Catlin

2012 VW Golf 2.5 5speed Deep Black Pearl
1999.5 VW Jetta TDI Bosch .216mm injectors and Malone stage 2, soon 11mm pump and vnt 22(parked for the winter)
2010 VW Golf City 2.0L "Hers"