17439 tuning valve

Chiefmechanic

Active Member
Bought my first a2 in September. A 2001 1.4 with a glass roof. Was so impressed that I bought two more. Sister in law took that one. I bought two 1.6 fsi models. A 2003 and a 2004. Daughter got the 2004 one and I have the 2003 with 92000 miles. Nice car but with a bit of lacquer peel but red cars seem to do that.

If that was the only fault I would be happy but it has the manifold tuning valve fault and associated random multiple and cylinder one misfire. Will accelerate ok if I build the revs up gently but under any load it runs lumpy like it is misfiring. I suspect the vacum side of the flap is not operating correctly. I have exercised the flap with Vagcom and seems to work ok.

Does anyone have a circuit diagram of the intake manifold system and a diagram with the parts labelled so I know what part does what.

Is there a manual to help with maintainence as Haynes don’t seem to do one and I like to do my own servicing.

Thanks Brian
 
Hi Brian
I find 7zap quite handy for parts and Diagrams, as they have the OEM parts photos and list part numbers and names ...
try this link as may be of help ..
https://audi.7zap.com/en/rdw/audi+a2/a2/2002-248/1/133-133005/

I do know the FSI's have a habit of snapping the plastic shaft that moves the intake flaps as a weak point and common fault as you mention the actuator seems to work possibly the shaft itself is snapped so the flaps or some of the flaps are not opening and closing , although just a guess and affraid i think its a strip down to be 100%...

hopefully someone knowledgable on the fsi will be along to help

Regards Gary
 
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Hi Brian
I find 7zap quite handy for parts and Diagrams, as they have the OEM parts photos and list part numbers and names ...
try this link as may be of help ..
https://audi.7zap.com/en/rdw/audi+a2/a2/2002-248/1/133-133005/

I do know the FSI's have a habit of snapping the plastic shaft that moves the intake flaps as a weak point and common fault as you mention the actuator seems to work possibly the shaft itself is snapped so the flaps or some of the flaps are not opening and closing , although just a guess and affraid i think its a strip down to be 100%...

hopefully someone knowledgable on the fsi will be along to help

Regards Gary

Thanks Gary. Very useful diagram
Brian
 
The plastic shaft is intact. Does anyone know what way the vacuum works the flaps and how to test it. I suspect it only operates under load independently of the Ecu.
 
The plastic shaft is intact. Does anyone know what way the vacuum works the flaps and how to test it. I suspect it only operates under load independently of the Ecu.

Hi,

the tumble flaps in the manifold should be in line with the airflow in "normal" engine mode and at an angle in stratified and lean burn mode. The latter only happens when the engine and exhaust are up to temperature, the NOx storage catalyst isn't full and the engine is running at specific loads.

The ECU adaption for the flaps will cycle them between the two extremities of their movement. You need to do ECU basic settings number 142 with VAG COM to run the flap adaption routine. This will allow you to see the flaps move and report if there is a problem. If the manifold is clogged with carbon deposits then this can prevent the flaps from reaching their correct positions. Worst case, the "blockage" can causes the plastic parts to snap.

Measuring block 142 should also show the expected and actual positions of the flaps. If there is an obstruction then this should show up as a difference. The adaptation should also fail with an error (rather than OK) message if the movement isn't correct.

regards

Andrew
 
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The plastic shaft is intact. Does anyone know what way the vacuum works the flaps and how to test it. I suspect it only operates under load independently of the Ecu.

As a basic test, suck it and see. I disconnected the vac pipe from the solenoid and sucked to confirm the actuator was working. I have since replaced the vac solenoid, the actuator now responds to the engine revving (though other issues still present). I used this solenoid (was £38.90 in Sept)...
https://www.amazon.co.uk/dp/B0068MZ4IW/ref=pe_3187911_189395841_TE_dp_1
 
Thanks for the info. I have performed the flap test at 142 and I get an ok. I also get a 0 and 100. It’s only when the car warms up and is under load that it runs lumpy. I’m sure it’s not a misfire. The temp gauge does not work although Vagcom says 94 degrees. I don’t really understand why the gauge stays at zero but Vagcom can tell the temperature.
Can anyone tell me if there is a flap controlled by the ecu and one controlled by vacuum as I think my fault is with the vacuum side of things. Brian.
 
So far as I am aware the flap test doesn't tell you the flaps are moving, just that the electrical side is correct. Happy to be informed otherwise.
Lumpy under load likely misfire or fuel injector /supply.
 
Did the flap test 142 and I can see the vacuum actuator moving in and out so happy enough it is sort of working. Changed the electric vacuum valve talked about above and the engine goes a lot better but there is still a fault somewhere. Changing the spark plugs today to rule that out.
Is there any way I can read the fuel pressure with Vagcom or is there an adjustment made by the engine when it warms up.
Brian
 
Thanks for the reply. Is there a way with Vagcom to tell if a cylinder is under performing. I always get the cylinder 1 and random multiple misfire. I have changed the plugs and coils around but the fault is still the same. Brian
 
So far I have replaced the spark plugs and it seems to run better but doesn’t tick over as smooth as I would like it. Changed the water temperature sensor which was a pita but the temperature gauge now works.
While I had VCDS plugged in I noticed the rpm on vcds was 680-740 but the Rev counter on the dash was indicating 200 rpm. Does anyone else have this indication and what does it mean.
While checking measuring block 20 the idle stabilisation figures were 0.0 across all 4 cylinders. Is this normal. What way does the 1.6 fsi control idle stabilisation. All help appreciated thanks.
 
Today Car runs very well when it is cold but as soon as it warms up I get a misfire. It seems like a permanent misfire on cylinder one.
Does anyone know where I can find a circuit diagram for the engine electrics.
Brian
 
I am not sure that a wiring diagram would help much.

I don't know the 1.4 petrol engine well, but the symptoms you are describing sound very similar to those you get on a TDI when the Crankshaft and camshaft position sensors start to pack up, or the loom to them has problems.

As I say, I am not sure if the 1.4 has these but they or the wiring harness to them could be the cause?

Just clutching at straws, but I guess that is all we can do.

Steve B
 
Thanks for the reply. The misfire seems to be on only one cylinder and I was going to rewire that coil pack back to the ecu or wherever it went. It’s a 2003 1.6 fsi. Brian.
 
Thanks for the reply. The misfire seems to be on only one cylinder and I was going to rewire that coil pack back to the ecu or wherever it went. It’s a 2003 1.6 fsi. Brian.

I suppose that you have tried swapping the coil packs between cylinders to see if the fault follws it to the other cylinder. If it does then it ias the coil pack that is the source?

But I would still check the crankshaft / camshaft sensors, they really could be a possible source.


Steve B
 
Looks like injector nr 1 fails...
OK when started from cold, misfires when warm seems to be a signature :(
 
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