My first go at vcds

Well I played around with it today. I did the scan and save first.then I lengthened the glow plug time from some info I found on here. Then I checked the injection pump timing. It was in spec but on the low end. It took 4-5 times moving the bolt but I got it right on the blue line on the graph. Then I checked the iq and it was 2.8-3 so I moved it up to 4 to lean it out a bit. I saw conflicting info on weather or not it will increase mpg but I figured I’d try it since I’m only getting 40.

Any recommendations on things I should check or change? This car is a mpg car for me. Is there any settings I should change to help that?I have other cars that scoot when I want them to haha.

But knowing me I’ll be looking into a tune soon. I can’t leave anything alone. Everything can always be better!

Try lifting the IQ to around 6, that's enough of a jump to see some benefits.
See how it runs. I hear ya' on the injection pump, doesn't take much.
I found the best way to control the amount of movement was with a light
hammer tap on the wrench.

Cleaning the intake is probably the next thing to consider; delete the EGR,
take a hard look at your exhaust. Do the fuel filter and run a can of diesel
purge through it. (Fill the filter with the DP)

Check block 13 for injector deviation. Adjust your gas gauge,,,,,,, etc etc

And now you've got VCDS, and clearly mechanically competent, do the
timing belt. You've got the high speed toys, now to work on the econo model. {)

Rrusse11 said:

Try lifting the IQ to around 6, that's enough of a jump to see some benefits.
See how it runs. I hear ya' on the injection pump, doesn't take much.
I found the best way to control the amount of movement was with a light
hammer tap on the wrench.

Cleaning the intake is probably the next thing to consider; delete the EGR,
take a hard look at your exhaust. Do the fuel filter and run a can of diesel
purge through it. (Fill the filter with the DP)

Check block 13 for injector deviation. Adjust your gas gauge,,,,,,, etc etc

And now you've got VCDS, and clearly mechanically competent, do the
timing belt. You've got the high speed toys, now to work on the econo model. {)

Click to expand...

Could you give me some info on block 13 injector divination? How do you adjust the gas gauge? I’m sure there’s so much I can do with this program. I just wish everything was labeled or they gave you a chart or something.


Fuel filter was done the first week I got it. I have never heard of diesel purge before. Thank you for the info I really appreciate it. Timing belt is on the list don’t worry

Oh exhaust looks good. I have a borescope I could probly take a peek at the cat with.

Trak,



With the caveat that I'm not the best person to ask about VCDS,
and I'm not plugged in to my car at the moment,,,,, here goes. You logged in, went to "Engine" control module, and then to adaptation.
BEFORE you go to adaptation lower right of the screen,
on the left is a button for "Measuring Blocks".
Click on that and you should get 3 or 4 blank lines.
LH side click up. You should get a series of readings.
Keep clicking, the various "blocks", each one different,
will give a variety of numbers.

Injector deviation is #13, showing what the pump is delivering to
each injector. The closer the #s are together the better, ie. each cylinder
is getting the same amount of fuel. If the spread is >2, highest to lowest,
your injectors could use some work.

Under the "adaptation"(after login) button, with your pull down menu , you can adjust eg. the idle. 910rpm is the preferred spec.

Gas gauge is under instruments. Better move yourself to the MkIV
forum, each engine series has a host of variations on these themes.
There are guys there that can be more helpfull with the program specifics
than me. You can check MAF readings, how your turbo is doing,
check EGR operation, etc.

It's a powerful tool for diagnosis and tweaking a lot of the basic functions. Lol, I'm no mechanic, or computer geek, I just like to drive.
Soon as I get it running the way I like, I leave well enough alone.

Diesel Purge is an injector cleaner and will help the injection pump as
well. Several threads about how to set up a couple of cans to run it
for 1/2 an hour or so on just the DP. Filling the fuel filter with it
gets a pretty good splash in there before it gets diluted. You can just
pour it in the tank, but full concentration will really clean up the fuel
delivery system.


Diesel IS different, and VW engineering is its own little world.

Deleting the EGR is not a mileage improver. In fact, many report losing a mpg or two.
For someone in CT it would be counter-productive due to longer warm-up times.
Local laws may forbid it too. Better to get a tune that has the 'dynamic EGR' feature.
Check the snow screen if you haven't done that yet and cut it out if it's still there.
These cars respond well to careful brake jobs that make sure nothing is dragging.
Most long-time owners end up replacing one or both rear calipers and keep an eye on 'em.

flee said:

Deleting the EGR is not a mileage improver. In fact, many report losing a mpg or two.
For someone in CT it would be counter-productive due to longer warm-up times.
Local laws may forbid it too. Better to get a tune that has the 'dynamic EGR' feature.
Check the snow screen if you haven't done that yet and cut it out if it's still there.
These cars respond well to careful brake jobs that make sure nothing is dragging.
Most long-time owners end up replacing one or both rear calipers and keep an eye on 'em.

Click to expand...

Yeah you have to pass emissions in ct. the snow screen is gone I checked it. I filled up today and only got 39mpg with probably 70/30 highway. Disappointing numbers. Any suggestions to get it up higher? Is raising the iq to 5 or 6 gonna help any? From what I’ve read on here I should get 45 easily if not more.

What I’ll do to check the calipers is measure the rotor temp on the fronts and compare them to each other and I’ll do the same to the rears. The fronts won’t be the same temp as the rears.

Trakpak said:

Yeah you have to pass emissions in ct. the snow screen is gone I checked it. I filled up today and only got 39mpg with probably 70/30 highway. Disappointing numbers. Any suggestions to get it up higher? Is raising the iq to 5 or 6 gonna help any? From what I’ve read on here I should get 45 easily if not more.

Click to expand...

A good alignment will help as will tires with lower rolling resistance.
Check the engine temp with your new VCDS.

Your driving is the biggest gain you will get from anything else you can do.

My injectors are -.16 .19 -.52 .47

I raised the iq to 5 and it felt like a slug so I knocked it back down to high 3’s

Lightflyer1 said:

Your driving is the biggest gain you will get from anything else you can do.

Click to expand...

I’ve always been able to get mileage outta cars when I wanted to. My old sohc saturns could get 40 without even trying.

I didn’t see the temp on vcds but when I had the torque App on it was 185 max temp. I’m gonna change the thermostat and coolant temp sensor just because. I’ll probably grab some g12 coolant at the parts store while I’m there too.

Trakpak said:

I didn’t see the temp on vcds but when I had the torque App on it was 185 max temp. I’m gonna change the thermostat and coolant temp sensor just because. I’ll probably grab some g12 coolant at the parts store while I’m there too.

Click to expand...

This will help your FE (fuel economy), pretty straightforward but the housing can be brittle.
The spring fails on the Tstat and it never gets to proper temperature.

Your IQ deviation is just fine, a good sign.

Sounds good. Anything else I should check to make sure it’s set up right? I was trying to do a boost log but don’t think I did it right. I’ll have to read up on it some more. It’s so easy to adjust the actuator rod id like to get it right where it’s supposed to be boost wise.

The maf was 510 at idle but I don’t think idle is how you check it.

Idle speed is 903 I have no idea if I can change it or not but I think 910 was where it’s supposed to be at but I’m sure 903 is fine.

Is it worth it mpg wise to get bigger injectors? I’m not sure of the cost as I’m a diesel new guy but I’m picking it up more power is good but I don’t wanna sacrifice mpg on this particular car.

Bigger injectors, more fuel, more power, less mpg, simple equation.
Now a basic tune with what you got may get a little bit better FE,
but get it mechanically up to snuff before you consider that.

The exhaust manifold is probably clogged up. A PIA to remove and clean,
but that's probably the next step to getting it running efficiently.

Fix the thermostat and temp sensor, figure out how to log boost.
The actuator rod on the turbo is an ez adjust, should start moving
at 3-5"hg, stop should be at 18. Boost logs should show whether or not
you need to touch it.

Winter diesel at the pump typically gives 2-3mpg less, they cut it with
kerosene to help prevent gelling.

You'll get there!