Failed MAP sensor?

[spikemoto]

The thing is, the symptoms I'm having simply does not feel like a vacuum/boost leak.. it feels more like an ignition or electrical issue than anything. I say this because it is not a soft cut like a misfire or boost leak but rather a hard sudden kill in function all together. This happens for a fraction of a second at which point the tach drops to 0 and springs right back up to where it was in a fraction of a second. If anything it feels more like the ECU is losing power but only at certain boost and/or torque levels....

[prj]

Fuel cut can feel like that.
Then again, you would have codes.

Check all grounds and also check ecu fuses, there were some thermal fuses as well iirc.

[UrS4boy]

Ignition related thermo fuses (or NOT)

Fuel cut can feel like that. Then again, you would have codes.
Check all grounds and also check ecu fuses, there were some thermal fuses as well iirc.

Thermo fuses would depend on how he wired the AAN into his CQ. The C4 UrS4s have thermofuses in the igntion but the C4 UrS6s do not and the S2s and RS2s do not.



UrS4 (with S75, S72 and S64) thermofuses:



UrS6 with no thermo fuses:



S2/RS2 with no thermo fuses

[prj]

To be honest, I never looked much at the electric schematic.
I mostly try to concentrate on the ECU and engine. The less car there is around it, the better

I just had a car that would do really odd things (shut off randomly) and it turned out to be a dodgy thermal fuse.
---

How is the ignition set up on this car?
Are you using COP's ?

I think I know exactly what is wrong with your car.

[UrS4boy]

The thing is, the symptoms I'm having simply does not feel like a vacuum/boost leak.. it feels more like an ignition or electrical issue than anything. I say this because it is not a soft cut like a misfire or boost leak but rather a hard sudden kill in function all together. .

I am not saying that is isn't electrical BUT... a boost leak is not necessarily a progressive thing. At least with the UrS4s and UrS6s, there can be splits in the Michelin Man hose and the cross-over pressure pipe that remain shut and no leaks up to that 15 psi(ish) range, and then BLAM!!, they open up and dump all the boost because the split is now open. Back off and it reseals. In the meantime, the ECU is confused as H*LL and might temporarily shut down to protect itself. While this could throw a code, it might not.

I still recommend testing your turbo to throttle body pipes and hoses using a combination of my and prj's hints but at higher pressures, i.e. slowly up to 15 psi but no higher than 20 psi. You might just find your problems.

[UrS4boy]

To be honest, I never looked much at the electric schematic.
I mostly try to concentrate on the ECU and engine. The less car there is around it, the better I just had a car that would do really odd things (shut off randomly) and it turned out to be a dodgy thermal fuse.

The electrical diagrams can explain a few things if you have the patience to follow them through.

You must have missed this thermo fuse thread in which I mentioned that some UrS4s are starting to shut down randomly as a result of a dodgy thermo fuse (easily cured by replacing the thermofuse with a normal spade fuse as the factory did with the UrS6s):

http://www.s2forum.com/forum/showthread.php?t=54002&highlight=thermo

[spikemoto]

Mailed Fap sensor?

I just had a car that would do really odd things (shut off randomly) and it turned out to be a dodgy thermal fuse.
---

How is the ignition set up on this car?
Are you using COP's ?

I think I know exactly what is wrong with your car.

My car is wired up with an ABY harness and AAN ECU. I am using the Apikol 1.8t coilpack conversion with the latest version of coil packs (06A 905 115D) I have heard of the 1.8t coils messing with the AAN ECU but never like this.

As for thermal fuses I don't remember coming across any while doing the wiring and the car ran flawlessly for the last 4 months since the swap until now

I tried swapping in a new ECU just to rule that out. The symptoms continued and it threw this code:

Friday,30,September,2011,14:17:31:09222
VCDS Version: Release 10.6.4 (x64)

Address 01: Engine Labels: None
Control Module Part Number: 4A0 907 551 AA
Component and/or Version: 2,2l R5 MOTR.RHV HS D03
Software Coding: PMC 1
Work Shop Code:
VCID: 62C158F2C4DF
3 Faults Found:

00533 - Idle Speed Regulation
10-10 - Adaptation Limit Not Reached - Intermittent
00561 - Mixture Adaptation
13-00 - Adaptation Limit (Mul) Not Reached
00513 - Engine Speed Sensor (G28)
03-00 - No Signal

Readiness: N/A

[UrS4boy]

My car is wired up with an ABY harness and AAN ECU. I am using the Apikol 1.8t coilpack conversion with the latest version of coil packs (06A 905 115D) I have heard of the 1.8t coils messing with the AAN ECU but never like this.
I tried swapping in a new ECU just to rule that out. The symptoms continued and it threw this code:3 Faults Found:

00533 - Idle Speed Regulation
10-10 - Adaptation Limit Not Reached - Intermittent
00561 - Mixture Adaptation
13-00 - Adaptation Limit (Mul) Not Reached
00513 - Engine Speed Sensor (G28)
03-00 - No Signal

I have never heard of 1.8t coils (or 2.5t coils) "messing with the AAN ECU". There have been some issues with coil drivers but these are happening on all coil systems including OE, 1.8t, and LS2. Doesn't matter, that is not your problem (most likely).

Idle Speed relates to the N71 Idle speed stabilization valve (ISV). It could be a dirty ISV valve or you have a vacuum leak somewhere. Here is some N71 info: http://forums.quattroworld.com/s4s6/msgs/21853.phtml

The Mixture Adaptation error would show up when you have a boost leak as I described above: All of a sudden the air that the computer thought went by the MAF and was heading to the intake manifold suddenly got diverted away (perhaps through a spilt hose, leaky clamp or split pipe) and, as result, the mixture was way too rich (the ECU had the injectors open for a period of time that was appropriate for the metered air, not for the smaller amount of air that showed up). The computer, via the signal from the G39 Oxygen (Lambda) sensor would try to back down on the fuelling but it can only do so much, given the RPMs and other signals that is was using. Hence "Mixture Adaptation Limit" error.

G28 - engine speed error = false positive that will always show up if you pull codes when the engine is stopped.

You really need to properly test your turbo to throttle body system and maybe the PCV system for leaks at 15 psi and above.

[prj]

I think your spark is not going where it should.
Also to use 1.8T coils you need to change dwell in ecu or they don't really last more than a year...

Check your spark plugs as well...

[shone190]

What do You mean by that?

Also to use 1.8T coils you need to change dwell in ecu or they don't really last more than a year...

[UrS4boy]

I think your spark is not going where it should.
Also to use 1.8T coils you need to change dwell in ecu or they don't really last more than a year...

No necessarily true. I have 1.8t coils from the very first AAN install that lasted (and are still good) from 2005 to 2011. Car is driven but not tracked. Tracked and a lot of high RPMs = dwell issue comes to forefront = heat = 1.8t coils die. Normal daily driving with bursts of WOT and they last quite well.

I switched to the red 4.2L V8 coils and kept the 115L (and 115R) coils as spares. (Coil packs cost about US$15 each).

[prj]

Well, stock dwell is 3x (yes three times) higher than it should be for 1.8T coils.
Mine lasted 1.5 year until they died.

If you fix dwell in ECU there should be no problem. Easier to just use 2.0/2.5 TFSI coils though, because they have overdwell protection afaik.

[shone190]

Do You have part number of 2.0/2.5 TFSI?

[shone190]

Part number of coils, off course

[prj]

Do You have part number of 2.0/2.5 TFSI?

07K 905 715 F