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Engine Specific Info and Questions => IDI Engine => Topic started by: speedball30 on March 19, 2006, 05:13:26 pm
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As you all may be aware, I am having a tad bit of trouble with the fuel economy on my 97 Jetta 1.9 TD. I did a fuel flush and had it looked at by a fellow Board member who found nothing to be wrong and suggested I was driving it too hard, treating her like a gas car.
I took his advice and really paid attention to the turbo gauge and tried to keep it under 7 PSI at all times. Tried to not giver on green lites etc.
I still was only getting 480-500 Kms per 55 L. So I finally broke down and took it to the local dealership. Below is exactly what I was giving on my bill....$115.92 BTW.
1. Checked oil filter element - OK
2. Snow screen - OK
3. Put car on TDC at crank & ing pump - lines up dead on
4. Check pump stroke - 1.15 mm
5. Brakes are not dragging
6. Adjusted tire pressures
7. Tried to adjust idle lower but the adjuster screw is siezed
8. We do not have tester for pump or injectors
Can anyone enlighten me on whether or not I just paid $115.00 to have my tire pressure adjusted or did he actually check something of meaning?
All in all, only thing he found to be wrong was the tire pressure. He said that for every pound of pressure the tire was out, I was losing 2 MPG. He said thats probably why I am getting such poor fuel economy.
No I may be a complete moron when it comes to diesels but to me something sounds out to lunch here. Even if you were driving the car with the boost at 11 psi all day, I still think I'd get more than 480Km's to a tank...or am I right the f*&^ out of 'er???
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What type of driving are you doing ?
Has anyone check the cat ? I'd bet it's plugged up,which can contribute to poor mileage.
How does the car perform ?
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Car seems to run fine, it is a little more pokey in acceleration than I thought she would be. Usually you have to make her want to get to a speed. I do a lot of city driving but not in stop and go traffic.
Never thought about the cat, is it hard to check/clean?
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$115.92 BTW.
1. Checked oil filter element - OK
- I'm assuming they unscrewed the filter and looked inside? Interesting.
2. Snow screen - OK
the one in front of the rad? Why would they check that? Might make your car run hotter, but wouldn't do much for fuel economy.
3. Put car on TDC at crank & ing pump - lines up dead on
if it didn't, you would have smoking and rough idle, which they might have noticed when they started the car.....then they wouldn't have had to do this check
4. Check pump stroke - 1.15 mm
this is useful. they checked your pump timing for you. That is worthwhile. A good check, but a bit pricey for that.
5. Brakes are not dragging
push car back and forth, hmmm, no dragging brakes. Either that or spin each wheel by hand while the car is off the ground.
6. Adjusted tire pressures
this one is funny. Can't believe they did that.
7. Tried to adjust idle lower but the adjuster screw is siezed
and being a VW dealer they of course couldn't do anything about a seized screw. Might not want to let them do your suspension...."tried to remove strut, but ball joint bolts were seized"
8. We do not have tester for pump or injectors
No they probably don't have that. Interesting they never checked the air or oil filter, or the fuel flow, or the condition of the transmission fluid, or the most obvious cause of low fuel economy on a diesel vw, THE THERMOSTAT! I would have thought that would be the first thing they would check.
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Even if you put the motor to the limit you must get at least 750 km.
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Can anyone enlighten me on whether or not I just paid $115.00 to have my tire pressure adjusted?
yes. after having worked at vw dealer for a year, generally the rule of thumb is, stay away from the dealer.
stick around here, these guys know their diesels and they'll fix you up. :)
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You'd have to do a backpressure test,to check and see if the cat is plugged.
It's easier to just remove or gut it.
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personaly i dont think that driving the *** out of the car will have a huge hit on fuel consuption. i drive my 85 jetta w\ 1.6 turbo to the limits every day. 4000 rpm shift WOT at every light and 140 km\h on freeway. the car run great with about 850km a tank. the tranny has 550 000km and the motor has about 50 000km.
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personaly i dont think that driving the *** out of the car will have a huge hit on fuel consuption. i drive my 85 jetta w\ 1.6 turbo to the limits every day. 4000 rpm shift WOT at every light and 140 km\h on freeway. the car run great with about 850km a tank.
sounds like how i drive mine. for some points of comparison, i get between 640-660km consistantly from a 45L tank. taking it easy on the highway i can get around 700-710km. worst is about 620km. 1982 rabbit 1.6L TD.
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He said that for every pound of pressure the tire was out, I was losing 2 MPG.
Sounds incredibly pessimistic to me... so starting at 35 you drop to 25 and she's doing 20 mpg less...? Maybe for all 4 tyres, maybe not. Think this is an absolute worst case scenario being misquoted for everyone's professional benefit :roll:
But you did take it to a VW dealer and commision the work.... whoever said thermostat, big Tick, and although diesels are less sensitive to pedal than petrols, it does make a difference as it has to! Keep accelerating a 1 ton mass faster than you need to, keep decelerating it 'cos you're going too fast - and if Mr Newton was still alive, he'd tell you THAT takes energy and energy is fuel!!! So back off a bit, read the road ahead, make early decisions and try to keep any monentum you do have - its called Advanced driving here, call it what you like over there, and it hinders everyone else less too... keep flowing and the rule is 'conservation of momentum', slower up hills and faster down the other side, constant energy driving, sacrifice kinetic for potential energy and vice versa. Over 65mph and the drag is going up out of all proportion to the reduction in journey time, our limits are 60 and 70 here, A road and M road respectively, about right, 80 mph and she drinks fuel - Fact!
PS. Have you checked your AIR filter is clean, its free to do so on a Sunday afternnon you know.............. one spanner?
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yeah, something is off for sure
my 97 jetta idi, i get a minimum of 725km per tank
id check the fuel filter, the nozzles, the cat, the air filter and for any air leaks in the fuel system
rico
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To all that replied, thanks a bunch.
I was 99% sure the only thing they checked that made sense to me was the pump timing.
So I will start with replaceing the fuel filter and removing the cat to give her a look see. I will have to break down and send my injectors to SMOG to get new nozzles installed.
Thanks a bunch guys.
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heres a funny,,if 1 psi tire pressure means 2mpg,,im going out to the garage rite now and putting 120psi in every tire,,,then im driving to california on 1 fill up,,ill get better mileage than the new lupo thanks for the tip!!!
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:twisted: bang boom :?: :!: :!: :?: :oops: why did all 4 of my tires blow out??it was just sitting there,,120 psi and everything,,,,,those guys didnt tell you too much,,the rest of the guys here are on track,,let the dieselgods of vwdiesel.net guide your chariot to good mileage+power!!!
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:twisted: bang boom :?: :!: :!: :?: :oops: why did all 4 of my tires blow out??it was just sitting there,,120 psi and everything,,,,,
Actually, I used to run my rear tires at 40psi. Then I had the tread separate on a cheap tire from this "overpressure" condition. The tire went wumpwumpwump, had to replace it. Any money I saved on fuel went into a new tire. :(
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Over 65mph and the drag is going up out of all proportion to the reduction in journey time, our limits are 60 and 70 here, A road and M road respectively, about right, 80 mph and she drinks fuel - Fact!
Speaking of the relationship of speed and fuel consumption, here are some results of a test done on a Porsche 356. This was done by a 356 Registry member with access to some high tech gizmos. (and maybe too much time on his hands)
First, a data recorder was hooked to the accelerator pedal to record throttle position. Then the car was driven back and forth over a flat and level section of highway at speeds of 45, 60, 70, and 80 mph. Then the car was then mounted on a dyno and run at the same throttle settings that were recorded from the two way passes.
The results:
45 mph: Too small to be replicable on the dyno
60 mph: 6.2hp!
70 mph: 12.8hp
80 mph: 29.2hp
At the risk of sounding like a greenie-weenie, it's easy to see why just slowing down is the easiest way to save fuel :roll:
Parasitic drag is bee-atch :x
moT
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Yep, know exactly what you mean, I drive my '86 diesel golf 104 miles round trip to work every day and only average like 40 mpg, at 70mph, but driving back and forth to my moms on the weekends on the back roads at around 45 to 55mph and I get closer to 47mpg.
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speedball30... keep us up to date. I'd really like to see what will make the greatest difference.
I bet it will be:
1)injectors
2)cat
3)tires
If I were you, I would put the timing donw to 1mm. 1.15mm seems a bit high! Each burning cycle produces less torque if timing is too soon in the piston movement.
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They told me the pump stroke could not be adjusted on my car....I'm gonna get my injectors to SMOG ASAP.
As for the cat, can I just cut the bottom off it and remove the inards and put it back together? Or is it simpler/better to cut it out and replace with a new section of pipe?
Thanks for the help
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As for the cat, can I just cut the bottom off it and remove the inards and put it back together?
You can remove the cat by disconnecting the pipe unions in front of it and behind it, then smash out the catalyst with a metal rod and a hammer. This is assuming it's legal for you to do that in your state/municipality, of course. :wink:
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Removing or gutting the cat is illegal.If you do remove it,it will fail the visual inspection part (they check for the cat) of the Ontario Drive Clean emission testing here.
If you gut it,you should weld a pipe through it,as it will resonate and make it sound funny if you don't.A good technician will hear this,and may fail it due to suspecting a failed or removed catalyst substrate.
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normally my first quarter of a full tank takes me to 200 km's. this tank i tried something different. right now im at about 330km's and im at a quarter :D
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normally my first quarter of a full tank takes me to 200 km's. this tank i tried something different. right now im at about 330km's and im at a quarter
What did you try that made such a difference :?: :?: :?:
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normally my first quarter of a full tank takes me to 200 km's. this tank i tried something different. right now im at about 330km's and im at a quarter
What did you try that made such a difference :?: :?: :?:
let me guess. you did not mash the 'diesel' pedal as much? :lol:
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normally my first quarter of a full tank takes me to 200 km's. this tank i tried something different. right now im at about 330km's and im at a quarter :D
cmon, did you do the vent trick to get every drop in there and drive like a nancy to get 330 at 1/4 tank? if you were to reasonably get 250 for each 1/4, that means 1000 per tank. on a 1.9 idi jetta, i would very much doubt that. so, i call bs on the 330km on 1/4 tank unless you can back it up with some info.
not trying to rain on your parade, but, this forum does not need unrealistic information like that floating around, imho.
rico
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A well tuned Jetta 1.9L TD will get over 1000 KM per tank if you baby it.I've done it a few times.
I've never gotten anywhere near 330 km out of the first 1/4 tank.My MKII Jetta gas gauge is like that (thens it goes down much quicker from 3/4 on down),but the MKIII's seem to get 250 KM or so out of the first 1/4 tank.
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well, shut my mouth.
i didnt believe it.
my best was 950
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Removing or gutting the cat is illegal.If you do remove it,it will fail the visual inspection part (they check for the cat) of the Ontario Drive Clean emission testing here.
If you gut it,you should weld a pipe through it,as it will resonate and make it sound funny if you don't.A good technician will hear this,and may fail it due to suspecting a failed or removed catalyst substrate.
as far as I can remember from having my diesel jetta drive clean inspected, all they ever did was stand behind the car and do a visual smoke-test. They never checked for a catalytic or hooked any testing equipment up to the exhaust. My jetta didn't have a cat on it.
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Your Jetta never came factory equipped with a cat,so there is no need to look for one.
The A3's have a sticker under the hood marked "CATALYST",so they should be looking for one.If the technician knows his stuff,he should also know most newer VW diesels have them,and he should check for it.
Some places are just lazy,and just start the car and look for smoke,they don't do the correct visual inspection to verify the other emission equipment is intact.Rewiring of the low speed advance control (if noticed),is also an emission violation,and they can fail it if they realize it.Best to make you mods clean and neat,so they look factory.They will never figure it out then.