Mkay... This will be a long one. My apologies for that folks. 
I start with the spec of the car so you know what we are dealing with. And then I take the problem and the questions.
Spec:
* Audi S2 Coupé 94, ABY
* RS2 intake manifold
* RS2 exhaust manifold
* RS2 and green bosch "968" fuel injectors (tested with both, more about that later on)
* RS2 turbo
* RS2 MAF
* ECU rebuild to meat RS2 spec, resistor changed and MAP sensor replaced to 3 bar
* RS2 350 hk chip with 1.6 bar in boost (also tested original RS2 chip)
* 7a exhaust cam
* 3.5" downpipe and race catalysator
* New Roose Motorsport silicon hoses (all big turbohoses and the MarkH mod on IC)
* Newly renovated WG (tested two different, more about that later on)
* Omori boost gauge and exhaust temp gauge.
The problems and symptoms:
When I put the pedal to the metal and give it full boost it overboosts and the boost pressure it flying through the roof and the engine cuts out. I have rigged my gauges and a lambda meter and filmed it all with various specs. It's hard to monitor the gauges while driving so this is how i did it.
1. First test can be found here:
It's, as the folder name hints, 350hk (359 is a typo) chip with the green 968 injectors. As seen on the to "50 to 220" movies the boost pressure hits the roof and then it cuts the fuel and it goes on like that. All movies are with swedish comments, sorry. WHen I should "KLIPPER!" it cuts out, as seen on the gauges. The pedal is glued to the floor in all these tests (...well... except the obvious ones where the engine is on idle. =)).
2. Test 2 with RS2 injectors and the 350hk chips
I have always had problems with high exhaust temperature with this setup. That's why I have the green 968 injectors instead of the original RS2 ones. But here is a couple of runs with the original RS2 injectors. Just to see if it was the injectors causing the problem. It wasn't... But notice how high in temp it runs. Also noticeable on the lambda meter that its running leaner. Same symptoms with it overboosting and cutting out.
3. Test 3. Original RS2 315 hk chip and RS2 fuelinjectors
This one is the "best" here: rs2chip.rs2inj.50.to.220.5th.gear.2.runs.AVI
Notice how unstable it is at full boost. The pedal is glued to the floor here to. Also see how hot it runs! It does not seem to cut the fuel here. But i did feel some of those "cut out symptoms", think i might be screaming "KLIPPER" in the movie to...
Mkay... So before all these tests the system have been pressure tested. No leaks what so ever. It's tested three or four times and with various hoses plugged and so. Most clamps on the bigger hoses are replaced to those babies with two allen keys, one on each side. Also swapped out nearly all small vacuum hoses and the one between the waste gate frequency valve (WGFV) and the waste gate.
As I wrote in the spec the waste gate is newly renovated and should be in excellent condition. But I did find out that this WG is from a 3B. The part number on the 3B and ABY are not the same, but i do not know if there are any real differences on them? That could be giving me problems? Anyways... The symptoms I have was, according to many people, classic waste gate problems. So I started to play around with various waste gate setups to see what happened. And this are the tests and results:
4. Test 4.
Here I have removed the hose between the WG and the WGFV and plugged it in the WGFV end. And the electric connector to the WGFV is removed. Then it's only the spring in the WG that should determine the boost. The odd thing here is that it only goes to 1.4 bar. I have been told that it should pretty much fly through the roof when "configured" like this? I did feel some hesitation on some of the tests at 1.4 bar. And as seen on the needle in the boost gauge it does wobble a bit and after a while on 1.4 it drops. But it does not cut the fuel, but guess that's because the WGFV is disconnected.
5. Test 5. Since i had it running pretty stable with the RS2 original chips at 1.4 bar I wanted to raise the boost pressure a tad. So I with the help of a 1 cm piece from a metal pipe I "bricked" (maybe bad name for it? =)) the WG spring up 1 cm. I know... not a nice solution, but just a temporary test.
The "bricking" raised the boost from 1.4 to pprox 1.7.
First run is this movie, WGFV is not connected and the hose between wg and wgfw is removed and plugged on the wgfv side: 350hk.968inj.bricked.MixedTests.5thGear.etc.1st.ru n.AVI
It does load more then 1.4 bar as seen. Still unstable and it does cut out. But it does not cut the fuel.
6. Test 6. The waste gate is still "bricked" but the WGFV => WG hose is connected as it should be and the wgfv is hooked up to it's power connector. 350hk.968inj.bricked.MixedTests.5thGear.etc.2nd.ru n.AVI
As seen on the last run in this movie it overboosts and cuts fuel and boost.
7. Test 7. Here I still have the hose disconnected and plugged but the WGFV is connected with it's power connector: 350hk.968inj.bricked.Floddy.Edition.3rd.run.AVI
Would say i get the same results as in test 5. Couldn't notice any difference.
Test 8. An interesting thing is that the boost pressure with the bricked WG and the wgfv not connected to power is 0.4 bar. The same as the original WG. I would have thought that it would go up 0.3 bar to around 0.7 bar it does that on full boost. A bit odd?
Test 9. Since there was a huge difference in temperature outside when I tried with the bricked WG and the unbricked WG it was suggested that I should rerun the tests on the original WG under the same conditions.
So I tried it with the wgfv => wg hose disconnected and plugged and the wgfv not connected to power.
And after that I tried with the hose disconnected and plugged but with the wgfv connected to power.
Pretty much the same results as on test 4 some pages up... Mkay, it loads 0.1 bar more but it was way cooler outside so nothing odd there.
I have had no fault codes related to this. Only one is the N75 one. But that's related to me testing without it connected. A read out from vag-com:
3 Faults Found:
01262 - Solenoid Valve for Boost Pressure Control (N75)
31-10 - Open or Short to Ground - Intermittent
00281 - Vehicle Speed Sensor (G68)
03-10 - No Signal - Intermittent
00513 - Engine Speed Sensor (G28)
03-00 - No Signal
As you can imagine I'm pretty sick of this. And so are probably you if you manage to read this far. =) There are a bunch of questions.
1. Are there any differences what so ever on the 3B and ABY waste gate other then the part number? Spring or other internal function?
2. Have anybody had these symptoms? What was the problem? Did you solve it?
I am sorry for the length of this post. And I hope that I typed in an understandable way and expressed myself clear enough. I hope to get some professional help from you guys. Thanks in advance!
ps. i might come back and change grammar and spelling in a while. =)
I start with the spec of the car so you know what we are dealing with. And then I take the problem and the questions.
Spec:
* Audi S2 Coupé 94, ABY
* RS2 intake manifold
* RS2 exhaust manifold
* RS2 and green bosch "968" fuel injectors (tested with both, more about that later on)
* RS2 turbo
* RS2 MAF
* ECU rebuild to meat RS2 spec, resistor changed and MAP sensor replaced to 3 bar
* RS2 350 hk chip with 1.6 bar in boost (also tested original RS2 chip)
* 7a exhaust cam
* 3.5" downpipe and race catalysator
* New Roose Motorsport silicon hoses (all big turbohoses and the MarkH mod on IC)
* Newly renovated WG (tested two different, more about that later on)
* Omori boost gauge and exhaust temp gauge.
The problems and symptoms:
When I put the pedal to the metal and give it full boost it overboosts and the boost pressure it flying through the roof and the engine cuts out. I have rigged my gauges and a lambda meter and filmed it all with various specs. It's hard to monitor the gauges while driving so this is how i did it.
1. First test can be found here:
It's, as the folder name hints, 350hk (359 is a typo) chip with the green 968 injectors. As seen on the to "50 to 220" movies the boost pressure hits the roof and then it cuts the fuel and it goes on like that. All movies are with swedish comments, sorry. WHen I should "KLIPPER!" it cuts out, as seen on the gauges. The pedal is glued to the floor in all these tests (...well... except the obvious ones where the engine is on idle. =)).
2. Test 2 with RS2 injectors and the 350hk chips
I have always had problems with high exhaust temperature with this setup. That's why I have the green 968 injectors instead of the original RS2 ones. But here is a couple of runs with the original RS2 injectors. Just to see if it was the injectors causing the problem. It wasn't... But notice how high in temp it runs. Also noticeable on the lambda meter that its running leaner. Same symptoms with it overboosting and cutting out.
3. Test 3. Original RS2 315 hk chip and RS2 fuelinjectors
This one is the "best" here: rs2chip.rs2inj.50.to.220.5th.gear.2.runs.AVI
Notice how unstable it is at full boost. The pedal is glued to the floor here to. Also see how hot it runs! It does not seem to cut the fuel here. But i did feel some of those "cut out symptoms", think i might be screaming "KLIPPER" in the movie to...
Mkay... So before all these tests the system have been pressure tested. No leaks what so ever. It's tested three or four times and with various hoses plugged and so. Most clamps on the bigger hoses are replaced to those babies with two allen keys, one on each side. Also swapped out nearly all small vacuum hoses and the one between the waste gate frequency valve (WGFV) and the waste gate.
As I wrote in the spec the waste gate is newly renovated and should be in excellent condition. But I did find out that this WG is from a 3B. The part number on the 3B and ABY are not the same, but i do not know if there are any real differences on them? That could be giving me problems? Anyways... The symptoms I have was, according to many people, classic waste gate problems. So I started to play around with various waste gate setups to see what happened. And this are the tests and results:
4. Test 4.
Here I have removed the hose between the WG and the WGFV and plugged it in the WGFV end. And the electric connector to the WGFV is removed. Then it's only the spring in the WG that should determine the boost. The odd thing here is that it only goes to 1.4 bar. I have been told that it should pretty much fly through the roof when "configured" like this? I did feel some hesitation on some of the tests at 1.4 bar. And as seen on the needle in the boost gauge it does wobble a bit and after a while on 1.4 it drops. But it does not cut the fuel, but guess that's because the WGFV is disconnected.
5. Test 5. Since i had it running pretty stable with the RS2 original chips at 1.4 bar I wanted to raise the boost pressure a tad. So I with the help of a 1 cm piece from a metal pipe I "bricked" (maybe bad name for it? =)) the WG spring up 1 cm. I know... not a nice solution, but just a temporary test.
The "bricking" raised the boost from 1.4 to pprox 1.7.
First run is this movie, WGFV is not connected and the hose between wg and wgfw is removed and plugged on the wgfv side: 350hk.968inj.bricked.MixedTests.5thGear.etc.1st.ru n.AVI
It does load more then 1.4 bar as seen. Still unstable and it does cut out. But it does not cut the fuel.
6. Test 6. The waste gate is still "bricked" but the WGFV => WG hose is connected as it should be and the wgfv is hooked up to it's power connector. 350hk.968inj.bricked.MixedTests.5thGear.etc.2nd.ru n.AVI
As seen on the last run in this movie it overboosts and cuts fuel and boost.
7. Test 7. Here I still have the hose disconnected and plugged but the WGFV is connected with it's power connector: 350hk.968inj.bricked.Floddy.Edition.3rd.run.AVI
Would say i get the same results as in test 5. Couldn't notice any difference.
Test 8. An interesting thing is that the boost pressure with the bricked WG and the wgfv not connected to power is 0.4 bar. The same as the original WG. I would have thought that it would go up 0.3 bar to around 0.7 bar it does that on full boost. A bit odd?
Test 9. Since there was a huge difference in temperature outside when I tried with the bricked WG and the unbricked WG it was suggested that I should rerun the tests on the original WG under the same conditions.
So I tried it with the wgfv => wg hose disconnected and plugged and the wgfv not connected to power.
And after that I tried with the hose disconnected and plugged but with the wgfv connected to power.
Pretty much the same results as on test 4 some pages up... Mkay, it loads 0.1 bar more but it was way cooler outside so nothing odd there.
I have had no fault codes related to this. Only one is the N75 one. But that's related to me testing without it connected. A read out from vag-com:
3 Faults Found:
01262 - Solenoid Valve for Boost Pressure Control (N75)
31-10 - Open or Short to Ground - Intermittent
00281 - Vehicle Speed Sensor (G68)
03-10 - No Signal - Intermittent
00513 - Engine Speed Sensor (G28)
03-00 - No Signal
As you can imagine I'm pretty sick of this. And so are probably you if you manage to read this far. =) There are a bunch of questions.
1. Are there any differences what so ever on the 3B and ABY waste gate other then the part number? Spring or other internal function?
2. Have anybody had these symptoms? What was the problem? Did you solve it?
I am sorry for the length of this post. And I hope that I typed in an understandable way and expressed myself clear enough. I hope to get some professional help from you guys. Thanks in advance!
ps. i might come back and change grammar and spelling in a while. =)
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