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Low mpg and power issue solved

thesoundone

Active Member
Apr 9, 2014
22
0
Hi

You remember a while ago I posted with an issue of very low mpg and flat power in my 2.0 TDI Sport (BKD) I was getting at best 38mpg average on the long term trip and on a long run with lots of downhills maybe pushing it to 48mpg on the short term trip. Mostly getting around 39-41 mpg.

I tried pretty much everything I could to resolve the issue including a full service (all filters), a good old thrashing down the motorway and a Terraclean. Nothing worked.

Anyway, someone advised me to check the timing and in particular the 'torsion' value using VCDS. I didn't have VCDS so I decided to wing it and adjust it and see what happened. Long story short it improved but I didn't know what the reading was exactly, so I borrowed a windows laptop (Mac only household), got a cheap cable off ebay and downloaded VCDS lite. My adjustment had advanced the timing quite a lot and was reading 4.3 in the 'idle stabilisation' measuring block (the last box in block 4) in VCDS. I was told that this should read 0.0. So I retarded the front pulley until it reached 0.0. I then adjusted the rear cam pulley until the fuel consumption (in block 15) had a reading of 0.40 l/h . After reading on the net it seemed that this was a good reading to have and would time the two cams together.

Anyway... Since I did this around 3 weeks ago my car is now averaging 47mpg on the long term trip and the best I have managed on a long journey is 64mpg. Also, the car absolutely fly's now :D So if like me you have a car that you know should be getting better mpg, maybe look at your timing adjustment...

If anyone wants to know a bit more detail on how I did this, just ask.
 

SNAP-ON

Active Member
May 24, 2009
103
0
Glad u got it sorted would like to check mine but do you have to time engine up each time u try to adjust a pulley ? Each adjustment you make u then to start and run car to see values and if still not correct do it over again ?
 

thesoundone

Active Member
Apr 9, 2014
22
0
No, what I did was get the engine up to temperature, take a reading from VCDS. The reading you want is in block 4 and its the last one on the right. You should have 0.0 in that box. determine whether or not you need to advance or retard the pulley (the front one) and undo the 3 bolts on the wheel then put an 18mm socket or spanner on the centre bolt and using a hammer tap the arm of the spanner in the direction you want it to go fairly lightly. It seems to me that adjusting it 1mm makes a MASSIVE difference to the reading, so adjust it just a hair, then do up the bolts and re-test. It took me about 4 goes to get it dead on 0.0.

When you've got the reading correct in block 4 go to block 15 and look for fuel consumption. Adjust the rear pulley in the same way until this reading is at 0.40l/h. Mine wouldn't idle properly if it dipped even slightly below this figure so it has to be accurate. I've still got the slight wobble at idle but I believe its normal on these engines. Just make sure you engine is up to temp every time you take a reading as these figure change as the engine cools.

All in all it took me about 20 mins.

Job done.
 

SNAP-ON

Active Member
May 24, 2009
103
0
I checked my values today and with warm engine im seeing 0.0 . My mpg is very good so i didnt bother checking block 15 . My intermitten lumpy idle has dissapeared since fitting a new oem maf sensor at £93 (even though i had no code for it) . Instead of getting around 100 miles for £20 worth of tesco diesel im now seeing 120miles so thats improved to :)
 

Mao

Active Member
Apr 27, 2010
108
0
Birmingham
Hello, im interested in checking my values. How much does vcds cost to download? Also would I need a laptop or would it work with an android tablet?
 

thesoundone

Active Member
Apr 9, 2014
22
0
I think VCDS only works on windows. You can download the VCDS lite for free but you just need to get a cheap cable off eBay or amazon. Mine cost about £10.
 

Bill55

Guest
I'm familiar with adjusting the torsion value on these engines, I did mine some while back but I have never come across an adjustment for the rear cam pulley. Is there a link to the web page where you got this information?
 

thesoundone

Active Member
Apr 9, 2014
22
0
I scanned quite a lot of forums and finally went down to my local VW/Audi independent and they confirmed that the rear cam has to read between 0.4 and 0.6 l/h. Although, they did say that it doesn't make much difference where its at! So wrong. Obviously the lower you go the less fuel you will use. Mine idles ok at 0.4 so I left it there. I'll see if I can dog out the threads I looked at when I'm back later.

Edit. When I say the rear cam has to read between 0.4 and 0.6 l/h I mean you change this reading by adjusting the rear pulley.
 
Last edited:

CrispDust

Dec 5, 2007
888
0
N W Leeds
thesoundone said:
I scanned quite a lot of forums and finally went down to my local VW/Audi independent and they confirmed that the rear cam has to read between 0.4 and 0.6 l/h. Although, they did say that it doesn't make much difference where its at! So wrong. Obviously the lower you go the less fuel you will use. Mine idles ok at 0.4 so I left it there. I'll see if I can dog out the threads I looked at when I'm back later.

Edit. When I say the rear cam has to read between 0.4 and 0.6 l/h I mean you change this reading by adjusting the rear pulley.
Click to expand...

Had a tweak on mine today. Front pulley was -1 so nudged forward - on my engine there is a metal back plate that moves relative to the sprocket which is usueful to measure with marks. overdid it to +1, knocked back a touch.
Rear pulley was at 06 l/h moved it back quite a bit to 0.4 but it wouldn't go any lower and idle remained steady. Almost ran out of adjustment in the vernier mechanism.
One word of caution - my rear sprocket bolt started to undo as I moved it back, so ensure it is fully torqued before you start (100 Nm)
Have to wait unitl tomorrow to try it out :)
 

thesoundone

Active Member
Apr 9, 2014
22
0
CrispDust said:
Had a tweak on mine today. Front pulley was -1 so nudged forward - on my engine there is a metal back plate that moves relative to the sprocket which is usueful to measure with marks. overdid it to +1, knocked back a touch.
Rear pulley was at 06 l/h moved it back quite a bit to 0.4 but it wouldn't go any lower and idle remained steady. Almost ran out of adjustment in the vernier mechanism.
One word of caution - my rear sprocket bolt started to undo as I moved it back, so ensure it is fully torqued before you start (100 Nm)
Have to wait unitl tomorrow to try it out :)
Click to expand...

Will be interesting to see what results you have. Sounds like it wasn't too far off anyway.. Good advice regarding the centre bolt. Its definitely a job you need a torque wrench for. I should have mentioned that earlier.
 

CrispDust

Dec 5, 2007
888
0
N W Leeds
An additional note, I realised whilst doing this that the adjustment is actually changing the rotational position of the camshaft with respect to the rest of the engine and timing gear (crankshaft, sprokets, pistons etc). With that I mind I did fit the sprocket locking tools (5/6mm rods) in place to ensure that I din't shift the rest of the timing gear. Don't use a 5 mm drill - they break too easily :)
 

CrispDust

Dec 5, 2007
888
0
N W Leeds
Well early results would suggest an improvement of 15-20%!!!
One of my usual work trips gives 50mpg on A road with average seed approx 30 and mix of 60 down to town traffic over 15 miles. Got 60mpg yesterday without any effort. Can't quite believe that. If its true then I may do a bit more adjustment a it was still runing smoothly on 0.4l/hr. :)
Of course the trim of the mpg may now be totally wrong and need adjusting on VCDS. Filling tank today so should see if mpg is correct or not in a week or so.
I have however noticed a slight hestitation on set off, but this could be DSG as I reset it at the same time and it may still be "settling in"
 
Last edited:

Mao

Active Member
Apr 27, 2010
108
0
Birmingham
This sounds like the best thing since sliced bread but how difficult is this to actually do? Looks definitely worth while but I'm not too sure what to adjust exactly and I don't wanna screw my car up. Any pics on the pully In question to adjust would be greatly appreciated :)
 

CrispDust

Dec 5, 2007
888
0
N W Leeds
If I do mine again I'll get some pics but a precis, on a BKD engine:
Get engine fully warmed up, plug in vagcom/VCDS and take reading from engine controller, block, 1st on left labelled "Torsion Value" - this should read 0 deg. If not then adjust by:
1. Remove cam cover (3 spring clips - 2 at front 1 at back quite low down - gloves advisable on a hot engine...)
2. On front cam sprocket, first check the centre 18mm is fully torqued up (100Nm) then mark the position of the toothed sproket to the shiny alloy plate behind with tippex or marker pen (just in case)
3. slacken off the three 13mm bolts. Then use long socket lever (for ease and precision) on the 18mm centre bolt - this turns the actually camshaft whilkst keep the sprocket in the same position relative to the rest of timing gear and crankshaft. Forwards to advance, backwards to retard. 1 deg requires a smidgen - well 1 degree actually....:blink:
4. Retighten bolts to 25Nm start up and take reading. You may need to do it several times to get 0deg
5. Then goto block 15 and look for Fuel consumption, should read 0.4l/hr. Same procedure is repated on the second rear cam sprocket, until you get this reading.
Don't forget to retighten the 3 13mm screws, and always check, if you are rotating camshaft anticlockwise, that the force required may start to undo the central bolt. If you have a sprocket lever ( I remember I have one now from my Alfa :whistle:) then use that instead/as well as socket.
And remember to chack torques again at finish.
Voila.
Then after a tasnk full check the MFD is still calculationg the corect mpg. I suspect mine is wildly optomisitc but if not then a 15% improvement in current mpg is bloody fanatastic!
 

CrispDust

Dec 5, 2007
888
0
N W Leeds
OK so the mpg reading on the mfd is pathologically optimistic, stating that I had avereged 49mpg over the past 350 miles. However the true mpg worked out at 42mpg which is still way better (15%) than the 35-36 I used to get. Half that milage included motoway fully loaded at 7*.

So out with the vagcom, crank if back a little more on the cams and adjust the trim for the mpg on the MFD.
 
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