Volkswagen MK4 TDI Fuel Mileage (HELP!!! Terrible Fuel Mileage with MK4 TDI)

[Nosej2645]

So I bought this my 2001 Jetta TDI 5 speed standard because I travel alot and heard of how good it is on diesel. But ever since I got it I havent gotton better then 750 kms to a tank, even though the previous owner said he got approx 1100 km to a tank. As most of you know, thats what your supposed to get for one of these cars. Hell, I have a buddy with a non-turbo diesel Jetta from the '80s and he even gets 900 km to a tank driving like an asshole. For some reason I cant even touch this.

Heres a little info on how I drive:

-I normally drive 80 kms a day on the 403 doing 120km/h
(I know the faster you drive, the more fuel you drink, but I have a friend who has a '00 Golf TDI and she gets 1000 km to a tank doing that speed on the 401)

-I have tried driving like a grandpa shifting at 2000rpm and driving like an asshole shifting at 2700 and 3000 rpms and shifting everywhere between, but I have only noticed a 10 km or so a tank difference

-I have also tried just driving in the city and country doing the speed limits and still, not a major difference.

Now the only thing that I can possibly think of that could be the reason of the poor mileage (and probably not the right one) is that the second day I had it, someone cut me off and I T-Boned him, and smashed up the front bumper off my car, as well as the grill, bent up the hood and damaged a few more things. It was deemed the other guys fault at the Cop Shop when I reported the accident, but as I later found out, the asshole that hit me gave me a fake insurance and license number, as well as a fake address and phone number. Bottom line, I cant afford to put it through insurance to fix it, and I cant pay for the damage out of pocket to fix it eaither. I have been driving around like this for a few months.

Anyways, Im thinking that I could have damaged a component or messed with the areodynamics of the car to the point where its eating my fuel mileage.

If you have any other clue why I could be having such crappy fuel economy or could confirm my thoughts on why Im getting it, I would love to hear it and would really appreicate it.

[The Weide Motors Kid]

is the engine light on? where do you buy fuel? also how bad is the damage? i cant imagine that would be the problem tho.

[Nosej2645]

is the engine light on? where do you buy fuel? also how bad is the damage? i cant imagine that would be the problem tho.

The engine light just came on like 2 weeks ago, I havent had a chance to put it on the OBD 2 yet, Ive been too busy.

I usually buy my fuel at Taylor Fuels in Galt.

The damage isnt that bad, just picture a jetta without the front valance, and bumper and what not. The hood is bent up, but i pounded it back somewhat into shape.

Im fairly mechanicially inclined (when it comes to American cars lol), but this really stumps me

[AudiDog]

Can't help you out too much with the mileage thing unless maybe your running rich or need a major tune up. Could try getting your injectors cleaned as well. Does the car smell gassy? Engine stuttering. You may need to redline the bitch once in a while to blow the shit out of it. Cause 3000 rpm isn't driving like an asshole.
'Anyways' isn't a word, 'anyway' is.

[EMSbyDay]

Well, not having seen the car or the codes I can't say for sure. But seeing as how your front end is smashed up and you have a CEL on I'd say you probably messed something up. Take your car to a proper mechanic and have it figured out. Yes, it costs money to do so, but at the same time your wastign money on fuel right now.

[CaptainSlow]

boost leak.

[Zuber Speed]

not much to go by, but there is something up with the motor

this is not an aerodynamics issue

Something was damaged in the accident. Im guessing intercooler or something

[Neb]

The engine light just came on like 2 weeks ago, I havent had a chance to put it on the OBD 2 yet, Ive been too busy.

I usually buy my fuel at Taylor Fuels in Galt.

The damage isnt that bad, just picture a jetta without the front valance, and bumper and what not. The hood is bent up, but i pounded it back somewhat into shape.

re-read what you wrote here.

if you can't afford a car, why have one? You wonder why you're getting crappy mileage and you've been driving around with a cel the past couple of weeks and haven't bothered to get it checked out? Do the basics before you go any further.

[Punjabi_Dubber]

We bought my dad a 2001 Golf TDI last october and the car was having the same fuel economy problems but worse. So im assuming you may be having similar problems.

1) Do you have boost? Do you hear the turbo spool up? If it doesn't it should be difficult to get up to highway speeds and you would notice a lack of power. This could be due to a leak as a cause of your accident or the wastegate actuator (vnt actuator) failing which is common on these cars. This will also result in poor fuel economy.

2) In the tdi world, you can't compare fuel economy based on kms per tank. You need a specific miles per gallon figure. It will be impossible to get 1000kms out of a tank of gas if you are filling until the pump automatically shuts off. Diesel is not nearly as combustible as gasoline and those that are getting 1000kms per tank are filling their takes right up until you can see fuel in the filler neck. Since diesel foams when your filling the tank, you have to burp the tank which is essentially letting air escape from the tank and settle the foam.

The burp valve is located on the left side of the filler neck on the inside. If you put your finger in to the neck or look in with a flash light you should be able to see it. When filling up your tank, place the diesel pump pipe against the burp valve on the filler neck of the car. You should be able to hear air escaping as your filling. Fill your tank up to the top until the fuel is about 1" below the gas cap. Then drive as you normally would and record how many kms until your low fuel light comes on. On the next fillup, proceed to fill the tank up the same way using the burp valve and filling up to the top and record how many litres of fuel went in. Then you can calculate an accurate miles per gallon value which will be better than comparing kms per tank.

This will help us in diagnosing how bad your fuel economy really is.

3) Get someone to scan your car looking at the timing chart with vagcom. This should be the first thing to do. I'm pretty sure somebody at the monday meet in cambridge usually brings their laptop and cable. Check to see whether the timing is out of spec. A little advanced is fine but if the timing is retarded, you will get poor fuel economy. It will also give you a chance to diagnose your engine light.

4) If that doesn't solve your problem it could be a number of other things. In order of what i would check
-dirty air filter
- clogged intake. The tdi intakes are notorious for clogging due to carbon build up. Let me see if i can get you a picture of what hose to take off and check.
-injector nozzles could be streaming fuel. nozzles can be replaced

But we need to know how bad your fuel economy is. On my dads, it was around the same as what your getting. 750 kms from fill up to the low fuel light. Our problem ended up being severly retarded timing. Most mechanics that aren't familiar with TDIs don't know how to do a proper timing belt job on these engines.

The type of fuel you buy also plays a large part in your economy. Try switching to shell. Thats primarilly what i use.

[Nosej2645]

re-read what you wrote here.

if you can't afford a car, why have one? You wonder why you're getting crappy mileage and you've been driving around with a cel the past couple of weeks and haven't bothered to get it checked out? Do the basics before you go any further.

I never said I cant afford a car. I bought it for $6000 and I paid cash, then an hour after it was put on the road, I spent $800 cash on it to do the timing belt. What I cant afford to do is spend $3200 to fix the body on it. Trust me, I got quotes. Now to spend that, plus whatever else I have to spend find and fix my fuel mileage problem for a car I only planned to drive for a year dosent make sense to me.

[Nosej2645]

Can't help you out too much with the mileage thing unless maybe your running rich or need a major tune up. Could try getting your injectors cleaned as well. Does the car smell gassy? Engine stuttering. You may need to redline the bitch once in a while to blow the shit out of it. Cause 3000 rpm isn't driving like an asshole.
'Anyways' isn't a word, 'anyway' is.

The car smells normal actually and the engines runs like a champ.

Well, not having seen the car or the codes I can't say for sure. But seeing as how your front end is smashed up and you have a CEL on I'd say you probably messed something up. Take your car to a proper mechanic and have it figured out. Yes, it costs money to do so, but at the same time your wastign money on fuel right now.

I agree with you there, but the check engine light came on awhile after the accident happened, leading me to beleive it cant be the CEL. Im going to put it on the OBD 2 tomorow night and find out for sure.

1) Do you have boost? Do you hear the turbo spool up? If it doesn't it should be difficult to get up to highway speeds and you would notice a lack of power. This could be due to a leak as a cause of your accident or the wastegate actuator (vnt actuator) failing which is common on these cars. This will also result in poor fuel economy..

Going on what you said Im not %100 sure I have boost. I have trouble getting on the highway (it takes me the whole on ramp length to get up to 100km/h) but I figured it was because a TDI isnt a fast car to begin with. The turbo whistle is extremely loud though, for a turbo of that size, much louder then any other TDI, and my friends have commented on it.

2) In the tdi world, you can't compare fuel economy based on kms per tank. You need a specific miles per gallon figure. calculate an accurate miles per gallon value which will be better than comparing kms per tank.

This will help us in diagnosing how bad your fuel economy really is. .

I have charted my MPG for the first 10 tanks of diesel. The list is in my car and Im in class. Ill edit it in to this post when I get back home.

3) Get someone to scan your car looking at the timing chart with vagcom. This should be the first thing to do. I'm pretty sure somebody at the monday meet in cambridge usually brings their laptop and cable. Check to see whether the timing is out of spec. A little advanced is fine but if the timing is retarded, you will get poor fuel economy. It will also give you a chance to diagnose your engine light..

Where is this Monday meet? This Monday ill go for sure.

4) Most mechanics that aren't familiar with TDIs don't know how to do a proper timing belt job on these engines...

Right when I got my car I took it to some place in Kitchener to do the timing belt. I forget the name off the top of my head I should have the receipt in the car. Ill edit that in to this post too. I should have taken it to Weide's.

[Raz]

My sister had an issue with the MAF on her '00 TDI that caused her car to be sluggish as hell. No acceleration whatsoever. I never asked her how her mileage was.

Apparently it was a "silent recall", the dealership replaced the MAF and the air filter at no charge (when the MAF toasted it burned the filter, that's nuts).

[Zuber Speed]

Going on what you said Im not %100 sure I have boost. I have trouble getting on the highway (it takes me the whole on ramp length to get up to 100km/h) but I figured it was because a TDI isnt a fast car to begin with. The turbo whistle is extremely loud though, for a turbo of that size, much louder then any other TDI, and my friends have commented on it.

sounds like its a boost leak

TDI is no slouch, and you should have NO problems getting up to highway speeds

Its probably an intercooler pipe or the intercooler itself that might have a hole?

Either that or the VNT actuator

Depending on how loud the turbo is actually spooling

Are you blowing a lot of black smoke out the back?

[Zuber Speed]

My sister had an issue with the MAF on her '00 TDI that caused her car to be sluggish as hell. No acceleration whatsoever. I never asked her how her mileage was.

Apparently it was a "silent recall", the dealership replaced the MAF and the air filter at no charge (when the MAF toasted it burned the filter, that's nuts).

good point, it could also be this

Get yourself a MAF from a 2.0 since its only ~50 bucks instead of 250 bucks for the TDI maf

[The Weide Motors Kid]

To make sure its the MAF, first of all check the codes, if theres no MAF codes, unplug the MAF and see if you have more power. if your power problem goes away with it unplugged then thats your problem. that way you know for sure.

Dont kid yourself man, i have driven stock tdis that could take down stock VR's.

You should be able to hear the turbo pressure leak, and that should be why your CEL is on if it is leaking. It would sound like air leaking out of a pressurized container.

Bottom line you need a scan.

[Chops]

Dont kid yourself man, i have driven stock tdis that could take down stock VR's.

lmao.....really? was the VR running on 3 cylinders or was the engine installed in a sherman tank?!

[euro.lo]

Lol! There's only a couple of diesels I kno of that can beat/keep up with my vr, and they aren't stock!

To the OP, did you bring it in and have it looked at? Any gains?

[dubonic possesion]

i'm with captain slow...BOOST LEAK ..what's right behind the bumper guys.?? intercooler.
i'd put money on a busted intercooler and you're throwing a boost deviation code for the cel

[Massecar]

If it sounds like a duck, looks like a duck, walks like a duck........it's probably a boost leak due to the accident.

[passatv6]

ive got a tdi and i noticed after i changed my fuel filter then my milage went up alot.so ive decided to change my fuel filter when i do my oil change.btw i have an 05 passat tdi

[Kei78]

when i initially got my tdi the mileage was also sub par...

I did a full tune up on it...

* Timing Belt kit
* 2 Micron Cat Filter
* Cleaned my intake mani (deleted EGR and cooler so it wouldnt happen again)
* swapped to sprint 520 injectors (original injectors were actually clogged, one wasnt even misting but rather pissing fuel right through it...)

oh, i just recently went to a high flow cat two weeks ago... my old one was clogged... also noticed an increase in mileage!

My vented gas mileage is close to 1150kms per tank unvented is close to 1000kms just as an fyi...

[Kei78]

ive got a tdi and i noticed after i changed my fuel filter then my milage went up alot.so ive decided to change my fuel filter when i do my oil change.btw i have an 05 passat tdi

Thats a little excessive... if you swapped to a cat filter it filters at 2 micron rather than the stock which filters at 10 micron. plus you can go 100 000kms before changing it. Ill be changing my cat fuel filter basically just before i have to do my next timing belt...

[Kmtdi]

I had a similar problem to yours
I had my timing belt done and shortly after went on a road trip. A few hours in I felt my 2001 jetta tdi lose power, turbo got loud and engine light came on. Problem turned out to be when the mechanic was putting everything back in place after doing the timing belt he didn't leave enough room for one of the belts (on passenger side) beside the air intake creating a hole which didn't allow the air to be properly condensed before going into the turbo. Apparently this is a somewhat common problem according to the mechanic who fixed the problem.
I also noticed increase in fuel economy by changing the MAF sensor and the air intake manifold. Hope this helps someone.

[Kmtdi]

I had a similar problem to yours
I had my timing belt done and shortly after went on a road trip. A few hours in I felt my 2001 jetta tdi lose power, turbo got loud and engine light came on. Problem turned out to be when the mechanic was putting everything back in place after doing the timing belt he didn't leave enough room for one of the belts (on passenger side) beside the air intake creating a hole which didn't allow the air to be properly condensed before going into the turbo. Apparently this is a somewhat common problem according to the mechanic who fixed the problem.
I also noticed increase in fuel economy by changing the MAF sensor and cleaning the air intake manifold. Hope this helps someone.