[1.6 Fsi] - Flap Actuator Debugging

Evripidis

Member
Hello all,

Before you say anything, I have looked for this on the forum but to be honest the amount of information is overwhelming and not really sure what is there to check other than taking the whole intake apart and have alook myself.

Is there a way of actually telling what causes the "Setpoint Not Reached" fault code? I understand there is an actuator and a potentiometer for the ECU to know about it. I did the following:

1. With the car off I tried moving the actuator rod gently. It did move with ease. I cannot see if it is broken though. Can you hear the flaps hitting the intake walls so you know they are not broken or their rod is not broken?
2. With the car still turned on, I unplugged the vacuum hose to the actuator and it hissed when sucking air in. I suppose there is no vacuum leak for that circuit?
3. Does anyone know what the resistance values are at the end of the rod's travel and which connector I can pick them up from so I can test please?

Any pointers are welcome.

Regards,
Evros
 
Hi Evros, I have the same issue so will watch this thread. I have changed the n316 and it has not made a difference that I can feel. The rod can be exercised through VAG COM using an engine output test (whilst off). I have done this and it will cycle the rod up and down for about 2 minutes which helps to observe if it is loose. The potentiometer that measures the setpoint is replaceable if you take off the cambelt cover and this is my next step. I have a manifold flap in pieces which may aid your diagnosis, happy to take some photos if that would help?
 
Hi,

Thanks for replying. Next time I meet with 67boris I will try and use his VCDS to figure out how. I think I have seen a description somewhere.

Do you have actual and valid resistance measurements between the flap's end positions; or can get any with a multimeter by any chance?

Regards,
Evros
 
I'm sorry I don't but happy to try to get them. I can tell you what to do in VCDS but don't have mine handy. It's quite easy when you get to engine output tests.
 
OK, I suppose I just run the output tests then, right?

I thought it was via the adaptation procedures for which I do not know much about just yet.

What I would do is compare the restistance values with the ones I have over here and see if it is the potensiometer to blame while moving the flap manually. The only way to move it manually is with a pair long-nose pliers with the vacuum hose disconneted.

I ought to spend more time to gather all the relevant "software" for servicing the A2; just so it happens other things get in the way.

Evros
 
OK, I suppose I just run the output tests then, right?

I thought it was via the adaptation procedures for which I do not know much about just yet.

What I would do is compare the restistance values with the ones I have over here and see if it is the potensiometer to blame while moving the flap manually. The only way to move it manually is with a pair long-nose pliers with the vacuum hose disconnected.

I ought to spend more time to gather all the relevant "software" for servicing the A2; just so it happens other things always get in the way.

Evros
 
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Hi Guy's,

I need to jump in here.

I've had this problem for ages, I did do a post on a fix for the broken vacuum arm and potentiometer repair but it only lasted 9 months after I'd glued it, anyway today I started asking around various independent Audi/VW specialists about removing the actuator and flaps altogether and checking the net too.

Here's what I've been told.

1. Swirl flaps are mainly for Diesel engines and can be removed and unusual on petrol ones, according to two mechanics. (mine is a 1.6 Fsi)

(Ps, I reckon Audi were having a laugh letting us know that the engine was "BAD" and FSI stands for "F'n stupid invention.")

2. I asked "What would happen if the vacuum valve pipe was blocked up with the flaps turned in the open position plus the Potentiometer turned to the same open position so that the resistance was telling the ECU it's open all the time?

All said, the car would run normally but fuel economy would suffer at start up an possibly harder to start.

What do you all think?

An Audi mechanic is getting back to me on this too, so I'll let you know what he says.

Meantime, I'm going to do the above while the diagnostics are attached, I expect it will say the usual "set point not reached".

To sum up; my car sometimes feels like it runs ok but most of the time it's got poor performance compared to when I bought it 3 years ago, I've done loads of work on it over these years with very many vast improvements, but just can't get the engine right at all. Fuel economy varies from 290 - 350 miles per tank - full to red low mark, approx fuel cost £35 - £41 per tank.

It is terrible on steep inclines ie; Lake District.


Cheers

Doug
 
Hi Doug,

I am trying to gather as much information possible before asking a fellow member for his VCDS.

I thought the swirl flaps on the diesels were used to generate a turbulent flow (hence smaller flaps of such geometry) whereas on the petrol they are used to vary the intake manifold length (hence bigger flaps of a simpler shape). In any case the engine could do without them despite not running optimally I suppose. In this case a proper fix would be removing them and then mapping the actuators/sensors out of the ECU's settings so it does not interfere with the rest of the air/fuel functions.

Regards,
Evros
 
From Bosch SSP 253


Intake process


In stratified charge mode, the throttle valve is opened as wide as possible in order to minimise throttle losses.
The intake manifold flap closes the lower duct in the cylinder head. The intake air flows at a faster rate and tumbles into the cylinders via the upper duct

Homogeneous operation at high exhaust gas circulation rates

Due to the intensive charging motion, the engine has a high exhaust gas recirculation compatibility of up to 25% when operated in homogeneous charge mode.
In order to achieve the same fresh air intake as at low exhaust gas circulation rates, the throttle valve is opened wider. This allows air intake against a low resistance, thereby decreasing throttle losses.

The throttle valve cannot be opened completely as a certain vacuum must always be present due to the activated charcoal canister system and exhaust gas recirculation.
 
To build on what steaman has explained, not having the flaps will not stop the engine functioning in homogeneous mode but will prevent it running in stratified. There is a noticeable difference in performance with the flap working either way though and would recommend fixing the issue if you can.

Assuming the control arm is intact, The most common failure is the solenoid valve that operates the control arm. It's easy to replace and I picked one up from eBay for a cool £12 some 8 months ago, I've had no issues since. Several different cars use the solenoid valve so it's worth doing a bit of hunting for a good price.

if you still have problems then the inlet manifold will need to come off to check the flaps are not jammed or blocked from full operation. It is less likely to be the potentiometer but not unheard of.

Nick
 
Hi Nick,

Much appreciated.

Moving the rod up and down is easy enough; one would assume the rest of the shaft is fine and the flaps can move but no way of knowing really whether they are broken or not. So in effect I could check the solenoid via the VCDS output tests along with the values. Do you know if I will be getting a different fault code if everything is fine but the flaps are broken?

Any idea what would happen if the flaps broke, I mean they are right next to the intake.

Evros
 
Again I think it’s very unusual for the flaps to break, they are of metal construction not plastic like many manufactures. IF they were to fail, it would be catastrophic.

When you test the solenoid through output tests you need to watch for movement on the arm.

It’s also worth testing the vacuum actuator by disconnecting the pipe from the solenoid and giving it a good suck, you should be able to see if the actuator is operating correctly.

Hope this helps and good luck!

Nick
 
Hi all,

Started doing this after a hiatus because of things.

So started taking out things to ccheck the thermostat (which ended up being shot). While at it I thought about removing the intake at the same time to check up on the flap issue.

I forgot to depresssurise the fuel rail and now I cannot do so because half the intake and cooling systems are dismantled. Is there another way of doing so without starting the car and let it stall? Can it be done slowly? Any info is welcome.

Regards,
Evros
 
I was told that you gently loosen one of the nipples to the high-pressure fuel line only secure that you have something covering any fuel spray. That will immediately depressurize the high-pressure fuel system.
 
Hi steaman; I did exactly just that but no fuel had escaped at all!!! Have I got another problem at hand with the fuel pump then? There have been no fuel-related problems in the past or DTCs.
 
I suspect the pressure disappear after a short while, I got the same result as you when I removed my manifold last year. No problem.
 
Never had a car with a mechanically-driven fuel pump before or of the high pressure sort for that matter so not really sure how it is supposed to work. You are correct I suppose. Still learning how this one works.
 
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