PD Engines - The Problem of Setting Torsion Value

Block 4 keeps reading 0.0 no matter which way I turn Cam

Hi Guys,
Trying to lower fuel consumption by going more - negative with the torsion value.
I started at -1.4 and turned the cam CC and expected a greater - negative number. It read 0.0 and idled really rough for a few minutes and stalled twice.
I moved the can forward a small amount and the Block 4 still reads 0.0 but the engine runs great and Block 15 went from .401 to .201 at idle and at 2000 rpm went from 1.401 to 1.201 so it is indicating less burn rate.

But, I don't understand why I am reading on Block 4 0.0 even with moving the cam forward from a know - position.
Could I be out of the sensing range?? in a large - negative range. I think I moved it well past the zero positing.
Is there a null position? If so, when I moved it some, it should of indicated a more negative or positive number, yes?
My Indicated MPG seemed to also get a Hugh increase so I would really like to know where it is at.
Block 13 is reading -.09 .02 .00 .05 at idle so they are pretty close.

Sounds like you are quite possibly out of the range. Torsion will read 0.0 if it's out of range.

Very Possibly could be out of range.
When I moved it further negative from -1.4 the engine stalled.
Then moved it forward or away from being so negative and engine started and ran fine but still shows 0.0 TV.
If I am still "out of range" it must be close to the most - number but the fuel consumption reduced to half what it was on Block 15.
I will run it tomorrow and see what the actual MPG work out to be.

lilpig88 said:

Sounds like you are quite possibly out of the range. Torsion will read 0.0 if it's out of range.

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Does zero (0.0) TV send that signal to the ECU

Since I am apparently out of range of the cam sensor because I get 0.0 TV on block 4, my question are:

1. Does the TV number send that number to the ECU to tell it when to fire the injector or is that number only given for the mechanic to see where the cam is in relation to the crank?

2. Is it the crank sensor telling the ECU when to fire the injectors?

3. Since I am out of range and the TV is zero 0.0 and the engine runs fine, I wonder what or where the injector id getting its firing signal.

4. (More Scary) Will the slot range on the pulley keep you from moving so far as to damage the engine by hitting a valve with the piston?

Block 15 at -1.4 was .401/h, at +1.5 it was .601/h at unknown - value it showed .201/h, then I moved cam Clockwise a fair amount to try to get back in range and the TV still showed 0.0 and the Block 15 also still showed .201/h. All Block readings were at idle.

Will run it today and see how it feels but would like some thought from anyone that knows any of the questions, Thanks

Why not apply the timing lock tools with the engine at TDC to get the Torsion Value back to near specification and then you will know that you are within range?

Great suggestion but don't have one. Would have to go back to shop many miles away or go to the dealer.

My thoughts are how far out could it be with the cam turned CC around 1/16 of an "?

Moving it forward back where it was should be an easy job.

The question remains, if I am out of sensor range by a tad, will the ECU care? or does it default to 0.0? Then only the cam would be retarded to an out of limit - negative value.

After reading all the post regarding TV on all the forums, it seem that the people in the know that work on these things have determined that the position of the cam (TV) is somewhat different in all the different configurations regarding slop, model mods etc and the sweet spot is determined with the person behind the wheel and how they like how it is running. Smooth- Economy-Low and or High end Power.

It is strange the the block 15 reading basically stayed the same when I advanced (Clockwise) the cam from its negative setting. Maybe I can move it forward a small amount until I get a TV reading and if the Block 15 changes to a higher or lower number.

By end of day I will post the MPG for today and the car is completely stock except for the addition of the catalytic fuel filter just before the main fuel filter. But that is a whole different topic and want to get better understanding of the TV reading and if they are sent to the ECU or not.

Lensdude_com said:

Why not apply the timing lock tools with the engine at TDC to get the Torsion Value back to near specification and then you will know that you are within range?

Click to expand...

If you have any additional questions, give me a call. Answers below:

MPG MASTERS 1 said:

Since I am apparently out of range of the cam sensor because I get 0.0 TV on block 4, my question are:
1. Does the TV number send that number to the ECU to tell it when to fire the injector or is that number only given for the mechanic to see where the cam is in relation to the crank?
The cam position sensor works in tandem with the crank position sensor. Cam sensor tells the next cylinder to fire. Crank sensor tells what timing.
2. Is it the crank sensor telling the ECU when to fire the injectors?
Yes and no. It must have the cam sensor feed or it's a 50/50 chance the crank sensor will get it wrong.
3. Since I am out of range and the TV is zero 0.0 and the engine runs fine, I wonder what or where the injector id getting its firing signal.
If you have a failed crank sensor, the engine will not run. If you have a failed cam sensor, the default is 0.0. The engine will default from the crank sensor and try option #1, then option #2. The choice being which piston is on the firing stroke.
4. (More Scary) Will the slot range on the pulley keep you from moving so far as to damage the engine by hitting a valve with the piston?
If you have the cam sprocket bolts centered in the adjustment with the crank lock and cam lock installed, you can move the adjustment all the way from stop to stop and not cause an interference hit.
Block 15 at -1.4 was .401/h, at +1.5 it was .601/h at unknown - value it showed .201/h, then I moved cam Clockwise a fair amount to try to get back in range and the TV still showed 0.0 and the Block 15 also still showed .201/h.
All Block readings were at idle.
We use the VCDS block 15 liter per hour block to get the engine to get some windage of the range of fuel usage. The lowest read will still be a range of about 1 degree. Once we find the range, we use block 13 for the lowest variance between injectors. We also will run block 15 at 2000rpm, looking for the lowest fuel usage. Usually around 2.4l/hr is relatively normal.
Will run it today and see how it feels but would like some thought from anyone that knows any of the questions, Thanks

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Ah, now I know who this is... a catalytic fuel filter says it all.

So, you didn't go with 'Our Cam'. Good luck...

Thanks Frank

When we ran at 2000 rpm the Block 15 went up to 1.201 from .201 When were were at a TV of -1.4, the idle was .401 and the 2000 rpm was at 1.401 so it seems to add 1 to the number from idle to 2000 rpm.

I think both sensors are working but seem to be out of sensor range on the negative side with the cam sensor.

If I am out of signal range to the ECU and it just defaults to 0.0 because it can't get a reading I wonder if the default 0.0 is the same as if I advanced the cam to a true signal of 0.0.

Last block 13 reading were #1 -.09 #2 .02 #3 .05 #4 .12 but they are wandering around somewhat at Idle. At 2000 rpm they are at -.44, .12, .19, .12

I think this engine likes negative numbers.

Maybe moving more Clockwise with the cam will bring the sensor back into reading range but wondering what the negative reading limits are.

Thanks Frank, you are the Guru of this stuff!!

Franko6 said:

If you have any additional questions, give me a call. Answers below:

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TV now reading again

You were 100% correct. I was out of limits and the system defaulted to 0.0 TV

Today I turned the cam clockwise just a tad and it now reads -5-8 to -6.3. So, I guess the limits are around +-7 since some have there set to -6.9.

I will go on a 200 road trip tomorrow and see if the mileage goes up some more. I have heard from some the around -4.8 yielded the best MPG but as everyone has said, your engine may like a sweet spot at a different TV setting.
One thing is for sure, the cam sensor tells the ECU when to fire the injector.

At -5.8 the car starts fine and runs silky smooth. Thanks for your input.

lilpig88 said:

Sounds like you are quite possibly out of the range. Torsion will read 0.0 if it's out of range.

Click to expand...

Don't invest too much faith in your MFD display especially at idle when altering cam timing (torsion). The ECU expects a certain pressure available during the injection duration and the tables in the ECU will display a calculated fuel quantity. Alter the mechanical point at which the pressure rises and the display will be wrong. I think there is some lattitude though especially at idle.

Optimising the cam for low consumption at idle will hurt tractibility and fuel consumption in the normal operating range of the motor. Idle cam timing is a compromise because we don't have variable valve timing.

The psycological effect of the numer displayed on the MFD is huge and overides common sense.

You moved the cam too much
And you are investing way too much time into this . Cam timing won't produce miracles

I agree, since I am moving all the lobs on the cam through rotation +- I am also rotating injector lob and altering ramp injector pressure. The ramp is building pressure to a high point and the TV number fires the injector and a happy medium of pressure and firing point needs to be just right for your particular engine and they way you want to set it up.

I do an idle and 2000 rpm on block 15 and so far it is showing a lower number at 2000 then before. 1.401 at -1.4 TV, 1.601 at +1.5, 1.201 at beyond range default to 0.0, and now, 1.001 at -5.8 TV. I only use the MFD at cruise to see if the indicated mileage seems to be higher or lower at highway speeds, then I fill up and do the math.

After today's driving I may try to get it closer to -3/-4 and then drive for a few days. My old bad cam was at -2.9 and the MPG were always higher then normal.

Mako said:

Don't invest too much faith in your MFD display especially at idle when altering cam timing (torsion). The ECU expects a certain pressure available during the injection duration and the tables in the ECU will display a calculated fuel quantity. Alter the mechanical point at which the pressure rises and the display will be wrong. I think there is some lattitude though especially at idle.

Optimising the cam for low consumption at idle will hurt tractibility and fuel consumption in the normal operating range of the motor. Idle cam timing is a compromise because we don't have variable valve timing.

The psycological effect of the numer displayed on the MFD is huge and overides common sense.

Click to expand...

I did move the cam too much and went out of view-able range and did get a code P0341. 00833 on snap on reader.

I don't mind playing with it when I see results one way or the other. I too think -5.8/-6.3 may be a little to negative but today 200 mile run will tell the story and if not confirmed some better mileage then I will go a little more clockwise and test again.

I read several posts where the owner did a graph and got the best mileage at -4.8 but I also understand each engine is a little different and the numbers posted may not be as accurate as you thought.

The engine runs very smooth and has lots of torque but I am only interested in higher mileage at present.

Thanks for your post.

I think this cam has a wider range to play with.

Dimitri16V said:

You moved the cam too much
And you are investing way too much time into this . Cam timing won't produce miracles

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Biggest impact to mileage is your right foot.

MPG, is there any number hand written on your timing belt cover? If so, and if it's still legible, that may be the factory setting.

Agreed, I always use Cruise Control at anytime I am on a road that I am cruising on regardless of distance traveled.

Today I traveled 233 miles and topped off the tank with 4.65 gallons, no bad since we were traveling 75 mph with A/C on. MFD said 55 mpg so it is off some.

Then I changed the TV to -4.4 and the only thing that was different was Block 15 went to 1.201 from 1.001 at 2000 rpm. I will run this TV setting for a few days and see if the MPG does anything more positive.

I wish someone would make a modular to change the TV number when the cam is at 0.0, peak injector pressure and valve position.

LNXGUY said:

Biggest impact to mileage is your right foot.

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Yes, Belt cover reads -1.6.

When the old shot worn out cam was checked it was at -2.9 and mileage was still in the higher numbers.

The cam installer put the TV at -1.5 upon my request, he normally sets the cams at 0.0 or -0.5 and with the -1.5 the mileage was a little lower which prompted me to go more negative. I just went to far the first time I move the cam. Since the modified cam has a wider range to play with the engine seems to run very smooth even with a larger negative number.

JB05 said:

MPG, is there any number hand written on your timing belt cover? If so, and if it's still legible, that may be the factory setting.

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New Strategy, You guys already knew about

One thing I may be missing and may have missed the boat. lol

I think if the engine delivers max power and torque,then a less pedal is required and FF should come down.

By going more negative in TV, I may get lower block numbers but this is not more power and would maybe require more pedal which in turn would burn more fuel.

I am going to reset TV to as close as 0.0 and see what the overall MPG do then.

I know my little MPG unit produced 20% more torque and consequently less pedal to go down the road. So, I may be think backwards, sorry but was fun and time will tell.

Hi Guys,

I have read that you can use your MFD to read ml/h fuel burn, true?

If so, how do you do it?

Is the number used to equate MPG on the MFD?

If so, the number could be inaccurate because it seems my MPG indicate a different number the pen and pencil.

Farnko says to use Block 15 on a road at a constant MPH LOAD and Direction which I think is correct but is that Block 15 number accurate?

Thanks

MPG MASTERS 1 said:

One thing I may be missing and may have missed the boat. lol

I think if the engine delivers max power and torque,then a less pedal is required and FF should come down.

By going more negative in TV, I may get lower block numbers but this is not more power and would maybe require more pedal which in turn would burn more fuel.

I am going to reset TV to as close as 0.0 and see what the overall MPG do then.

I know my little MPG unit produced 20% more torque and consequently less pedal to go down the road. So, I may be think backwards, sorry but was fun and time will tell.

Click to expand...

Update

Well, I have been moving TV from -5.8 to + 3.4 and everywhere in between. The engine runs smooth at all TV numbers but the MPG do change. More positive TV +, seems to produce more overall power but the fuel efficiency does goes down. More negative - FE goes up and overall power is fine throughout the Torque band.

Also:
During the process I have noticed that the on board MFD is completely useless as an accurate way to read average mpg. It seems the more negative you set your TV, the more inaccurate the MFD is in a false indicate gain in MPG. The only way to compute MPG is with a pen and paper which is the way I am doing to see the accurate differences in true MPG and false MFD readings. It seems some posts are reading higher MPG but if it is a result of MPD reading during TV changes, they could be very inaccurate.

Block 15 @ 2000 and 2500 RPM is a guide but what is it really telling you?
Okay, it reads lower the farther negative you set the TV. But, is that because you are reducing the total power of the engine by (kind of) leaning it? And, how far is to far in a negative reading? Beyond -7 (or + 7) it will default to 0 because it seems to be "out of range." The normal cams would probably not run to smooth at these extreme setting but the reground cams seem to do fine.

Being that each engine is somewhat a little different with "slop" in the TB system your overall feeling and MPGs wanted will either put you in a + setting for more power or - setting for more MPGs. Without have a dyno to do HP/TQ reads during TV adjustments, it is anyone guess. And, if you had a dyno, what would you shoot for? The higher the torque goes should require less pedal to keep you cruising which "should" reduce the fuel, yes?

All in all, I am a little disappointed with the MPG with the new cam but not done with a few other inbetween settings.

How is everyones reports going? After my tb my bew is set to +0.6 - +1.1 and i've dropped from 5.8ltr/100km to 5ltr/100km. It also starts and idles alot better

I recently changed my TV from +1.0 to 0.0. There is a slight improvement in mpg, but the low end torque is a wee bit lower.

I know its a later model than my BMR emgine but has anyone got any idea what the writing is on my cam cover? I have had to replace my cylinder head as the old one was cracked and could not get the values before the work was carried out :-(

I think it says " MADE IN CHINA"

JETaah said:

I think it says " MADE IN CHINA"

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Thanks for that!

Anyone got any clues? It seems German engineers were not known for their handwriting skills! All this being said it does look like it could be -.15?

I don't see a picture.

Could someone please help me here, I am looking to either advance my timing or retard it. I have read that timing for BEW engines should be in the 2-5 range but myturbodieseldotcom shows him putting it to 0.5.

Should I go ahead and set timing to 2 to 5 or 0.0 to 0.5

Engine does shakes a little ( I dont remember it shakes before...and use to turn on right away, now its I would say its a longer crank to start )

Here a pic of measuring block in VCDS
http://pics.tdiclub.com/showfull.php?photo=118349

Play with it until you find what works for you.