Hi Everyone,

I got my VCDS (VAGCOM) ordered directly from Ross-tech US recently and started my tweaking to my Yeti (5L Chassis). Few of the things that I have been able to do successfully so far to my Yeti:

1) Idle RPM increase from existing 775 rpm to 845 rpm. This was one of my major concern areas, as the Yeti would tend to stall in 2nd and 3rd gears at low rpm. Now it does not stall at all and has sufficient power to pull through.

I did this by going to the engine controller 1, then adaptations 10, and then the first drop down in the top bar - Idle rpm adjustment. You can enter a new value for the RPM offset - I entered 70 rpm and the new idle rpm is now 845/ min.

This does not require any login and can be done safely. I have not tried the max range, but think that maximum it can be adjusted till 975 rpm.

2) Auto Lock on speeds above 15kmph : This is available in the adaptations for Central electricals Controller and you can set the value to 1 (from existing 0) to switch it on

3) Single button press unlock for all doors: I have configured it for opening all doors and boot in single press. This is also available in the drop down menu in the adaptations in Central electricals.

4) Dial staging: Enabled the dial needles to sweep on startup. This is available in the adaptations on the Instrumentation controller.

All these options were enabled using VCDS latest version 10.6.4 and genuine Ross-tech cable and without the need for any Login details / SKC code on my Skoda Yeti (Nov 2010 manufacturing date).

I will also attempt to switch on the DRLs and the cornering fogs next on my Yeti.

There are some additional areas where I need help from experienced VCDS users.

Is there any way to increase the HVAC effectiveness. I feel that the AC cooling is not sufficient and take a long time to cool. Some of the adaptations visible in the HVAC controller are for Compressor run-up time (120s) and Duty cycle .. does anyone have any experience on this and can help me out?

Look at the MBs for 'A/C Regulating,Valve (N280)'. The valve is controlled by a 500Hz PWM signal. You can get a good idea of how quickly the system is trying to cool by the position of this valve. If the AC is running at maximum cooling and the AC has been serviced, there is nothing you can do.

What is the value after 2 minutes (there is an intentional delay of 2 minutes before the AC kicks in)?

Look at the MBs for 'A/C Regulating,Valve (N280)'. The valve is controlled by a 500Hz PWM signal. You can get a good idea of how quickly the system is trying to cool by the position of this valve. If the AC is running at maximum cooling and the AC has been serviced, there is nothing you can do.

What is the value after 2 minutes (there is an intentional delay of 2 minutes before the AC kicks in)?

Hi RWBaldwin,

Thanks for your guidance. Can you guide me on what is the measuring block number for the AC regulating valve. Are there any settings for the valve which I can change to improve the cooling. Also, if I change the compressor run-up time from 120s to 60s, would there be any detrimental impact on the compressor life and would it improve cooling?

Thanks!

Edited 21 August, 201114 yr by sameerdass

The AC uses PID control. When you first get in the car with a big temperature 'error', the Proportional ('P') component ensures that AC compressor is working at it's maximum.

The compressor run-up time is present to protect the engine as much as the compressor - you want as little load on the engine at startup as possible, so cooling at maximum is the worst case.

Other manufacturers using the same compressor have been more intelligent at startup. They tend to limit Kp (Proportional multiplier) instead of turning the compressor to minimum (2%).

I've seen a technical note stating that the compressor run-up time should not be reduced, as it interferes with the ECU idle stabilization routine.

Changing some of the AC settings can cause instability in the control loop so I would leave them as they are.

The limiting factor is the capacity of the compressor. If you have 40°C ambient and an internal temperature of 60+°C, it will take time.

There are more efficient refrigerants (30+%) that are a drop-in replacement for R134a, but these would void your warranty. You can ask locally to see if anyone uses them.

Hi there.

Is there any way to set the idle rpm of the engine when AC is on?

It seems that when the AC is on, the engine runs at higher RPMs. I do not want to change the

regular idle RPM, only the one when the AC is on. Is this a seperate setting?

The reason I want to do this is because I have a 1.2 TSI Octavia with DSG gearbox, and when the engine runs on higher idle RPMs (when AC is on) I have to put alot of pressure on the brakes in order to keep the car stationary (at traffic lights etc...). When the engine is running at standard RPM, when AC is off, I don't have to brake as hard in order to keep the car from moving.

Any help on this would be appreciated. I have a friend with VCDS.

Hi there.

Is there any way to set the idle rpm of the engine when AC is on?

It seems that when the AC is on, the engine runs at higher RPMs. I do not want to change the

regular idle RPM, only the one when the AC is on. Is this a seperate setting?

The reason I want to do this is because I have a 1.2 TSI Octavia with DSG gearbox, and when the engine runs on higher idle RPMs (when AC is on) I have to put alot of pressure on the brakes in order to keep the car stationary (at traffic lights etc...). When the engine is running at standard RPM, when AC is off, I don't have to brake as hard in order to keep the car from moving.

Any help on this would be appreciated. I have a friend with VCDS.

Virtually all cars increase the idle speed when you switch the AC is on. This is necessary to maintain idle stabilization when the engine is loaded by the compressor. You can't change this, as doing so would cause rough idle and would be bad for the engine.

I'm assuming you don't have a fault. What idle speeds do you see with the AC on and off?

Virtually all cars increase the idle speed when you switch the AC is on. This is necessary to maintain idle stabilization when the engine is loaded by the compressor. You can't change this, as doing so would cause rough idle and would be bad for the engine.

I'm assuming you don't have a fault. What idle speeds do you see with the AC on and off?

When scanned by VCDS a few days ago, no faults were found, but I forgot to check the RPM VCDS displays (I'll do it next time I go to my friend).

Looking at the RPM gauge, the idle RPM is around 700, and when the AC is on, its at 800.

These RPMs are actually low, but what annoys me is the need to hold the brake pedal pretty hard,

in order to make the clutches disconnect. Maybe the problem isn't the RPM ?

The connect/disconnect of the clutches is noticable when AC is off. When I slowly release the brake pedal, at some point the clutches start to engage. When AC is on, as soon as I release the brakes even a bit, they engage and the car starts to pull forward.

When scanned by VCDS a few days ago, no faults were found, but I forgot to check the RPM VCDS displays (I'll do it next time I go to my friend).

Looking at the RPM gauge, the idle RPM is around 700, and when the AC is on, its at 800.

These RPMs are actually low, but what annoys me is the need to hold the brake pedal pretty hard,

in order to make the clutches disconnect. Maybe the problem isn't the RPM ?

The connect/disconnect of the clutches is noticable when AC is off. When I slowly release the brake pedal, at some point the clutches start to engage. When AC is on, as soon as I release the brakes even a bit, they engage and the car starts to pull forward.

Those RPMs are normal.

There is a ECU/DSG update for the 1.2 that addresses some idle transition issues. You should contact your dealer to check if it is applicable to your car.

As i certain you are aware, DSG isn't a torque converter automatic, so you're effectively riding th clutch. Put the car in neutral (as the car is designed), with the handbrake on (as the car is designed) and the car doesn't need to be held on the brakes.

As i certain you are aware, DSG isn't a torque converter automatic, so you're effectively riding th clutch. Put the car in neutral (as the car is designed), with the handbrake on (as the car is designed) and the car doesn't need to be held on the brakes.

Yes I know, and when the AC is on, it really feels like I'm riding the clutch.

I have started using neutral in longer stop lights or in traffic jams lately, but find it a bit annoying.

Thanks for the info.

Yes I know, and when the AC is on, it really feels like I'm riding the clutch.

I have started using neutral in longer stop lights or in traffic jams lately, but find it a bit annoying.

Thanks for the info.

If you've got your foot on the brake, both clutches are disengaged - there's no slipping involved.

At idle the DSG 'soft-engages' when you release the brake. It sounds like your car isn't distinguishing between increased idle for the AC and you pressing the throttle.

I don't know if this is fixed by an update, but I drove a similar car to yours today and it was smooth when I released the brake at idle - with or without the AC on. In both cases if I raise the throttle by 100RPM as I release the brake, the clutch engages more quickly.

Thanks for your response, RWBaldwin!

I have noticed that in my Yeti (140 HP), 4x4 the engine idles at 775 rpm - I have increased this to 850 rpm, to reduce the stalling tendency. Also, in my Yeti, inspite of the AC on, it used to idle at the same speed, even with AC on, which used to put the AC regulation valve at minimum position on startup or when speed fell below 15km in 2nd gear (rpm around 850).

Unfortunately, this type of AC programming can cause discomfort in stop-and-go traffic, as the outside temperatures here are often 40 degrees Celsius and the compressor virtually shutting out for even 30 seconds makes the car quite hot. I wouldn't want to mess with the HVAC settings too much, so I tried to solve it by increasing the idling speed of the engine. This has resolved the problem 50%.. but I would still look forward to some solution which can resolve this issue completely!

Thanks!

You could try using the handbrake instead of the footbrake

It's also much more pleasant for the person behind.