ABY ECU Intermittent issue

[twoqu]

Part of the problem is that we don't really know what you have done in terms of wiring and plumbing!
I was only trying to give some information that might be useful IF you have the MFTS connected up and the overheat signal goes back to the ecu. If you don't then its not the cause.
However we know that on S2 models, the MFTS can give either a faulty or genuine overheat signal which will cause the ecu to stop activating the wgfv to give the basic i.e safer mechanical boost limit of 0.4bar. This function does not appear on S4/S6 models. Not sure whether its in the SW or not.
The MFTS provides the temp gauge signal and 2 overheat signals in the S2. This is not the sensor in the rear of the head as that is just for the Motronic. Normally its easier to just disconnect the MFTS to prove/disprove a problem as its easier to access for us. The same of course might not be true for you. Can't see thats it its necessarily a good idea to keep opening the ecu up.

[twoqu]

Here is what Uncle Dave has to say on the matter:

http://forums.quattroworld.com/s4s6/msgs/22584.phtml

[edge_devil]

Disconnected MFTS still only 0.5.... THEN...I realised I need to put my foot down to get full boost so it may not be the MFTS, just me taking it easy.

I now get a good solid build up to about 1bar that stays there until I let off, as opposed to a massive thump in the back, boost to 1.5 and at 4000 rpm it's all gone, which on it's own was a lot quicker but a lot less reliable or easy to drive.

I have had a few momentary 'coughs' from the ECU that I need to check out, I'm not sure if everything dies as in power failure, or if its a G68 failure for example, but one step at a time, the turbo and wastegate seems to be working well at last, not least thanks to your collective assistance

Now debating if I take the risk to drive to a customer meeting in Milton Keynes tomorrow morning to give it a good shake down.....

[edge_devil]

Here is what Uncle Dave has to say on the matter:
http://forums.quattroworld.com/s4s6/msgs/22584.phtml

He does write some good stuff doesn't he

[twoqu]

Thats the trouble with gauges. If you don't have one you are blissfully ignorant of whats going on and if you do have one you constantly wonder if everying is all right!
Having said that it is a useful addition even just from a diagnostic point of view. You need to know whats going on in the boost department.
Hopefully you should be in the stock drivability mode so the vehicle should be reasonably civilized!

[UrS4boy]

He does write some good stuff doesn't he

(I try )

[edge_devil]

Well the 5 hour round trip went well, just a short list of things to do that I was already aware of, and one new issue, but I'll dive back into the garage for that because I think I have a solution already....

Just so you know the list:

Cooling, she runs a bit warm, especially when the ambient temp creeps up, so I need to direct air into and out of the radiator and oil cooler better, basically a question of fabrication.

Low throttle hiccups, if you drive like hoon she goes fine, but sedate just off idle driving can lead to massive hiccups. The idle position sensor is fine, I think this may be down to something someone pointed out earlier about the distance between the air filter and the MAF. I'm not sure but I don;t think I had this issue with the Nero chips so I am wondering if they were a MAFless map, chalk that up as one to look at in the future.

Fuel Economy isn't looking too bad either, 143 miles of varied driving required 19.10 litres of fuel, so about 34 mpg which really isn't that bad!

....now back to work and decide if I use her to drive to Leeds tonight... circa 4.5 hours, maybe too much of a good thing!

[twoqu]

The only person offering Mafless is PRJ and that is after years of experience. In fact if you went to spend money and it helps with your packaging and it eliminates an increasingly hard to obtain and costly component, I would certaintly give that some consideration. Its not as if being stock is a consideration. You would have to consult with him over the suitability. So those Nero chips are definitely not Mafless!
Obviously it is unreasonable not to expect a few glitches. Nevertheless it is encouraging progress.

http://www.s2forum.com/forum/showthread.php?t=71709

[Nero]

Zou wel kunnen kloppen want de motor en ecu is Nederlands

I'll send him a message he may be able to help. On a side note, where can I get the upgraded MAP sensors?


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Well, the ecu has been here, that's for sure. But as you can see on the outside of the ECU, I have a labeling machine. Chips that came from me will have a white printed label on them.

[edge_devil]

Thanks Nero, looks like someone's had a play before it got to me. Seems to be running well on them though, whatever they are...

[Nero]

Maybe they've put new labels on them. The engine chips looks like the OTP chip that I've used sometimes.

If you can readout 1 of the 2 chips and email/send me the *.bin or whatever, I can always compare them with my database.

[edge_devil]

I don't have a reader but I can use vcs lite to let you know what the codes are if that helps?

[edge_devil]

I don't know if anyone is subscribed to this thread still... But an update.

Fixed plumbing issues and loads of other things have done about 1500 miles and have oneirritating issue, misfire at WOT. Tonight I went out and put the stock ecu chips back in and although boost has dropped from 2.2 to 1.8, the WOT issue has gone..... Soooooo the chips are home-fry of unknown origin the MAP sensor in the ECU is standard everything else was unchanged, what could be causing my WOT issue if the std chips work fine. Is it down to that extra .4 of boost popping a pipe. Or is it just too much for the ignition coils? I can't see anything obvious but have got a spark tester I was going to have a play with.

Answers and hints welcome!

[twoqu]

Not sure how the guage is calibrated but its either not enough or too much boost pressure!
Stock is @1.1bar above atmospheric and modified would be nearer 1.4 bar. So you need to clarify that issue.
Obviously more pressure causes more stresses on components, be they hoses or other components.
The usual mantra is pull codes and check for boost leaks. There is no way to test the coils other than to life them. If they are original OE then they are at least 20 years old. They are expensive to replace so that has lead to replacement with other more modern coils which eliminate other possibly troublesome ignition components (POS).
This means a loom and 5 new coils at least.

[edge_devil]

Hmm... So no codes last time I looked, gauge is after market and because of the engine being in the back is over a 3m hose, not sure if that impacts the reading. I'll have to set up the gopro and film the gauge so I can analyse it better instead of trying to look while driving.

Re the coils I had started looking at that option, what I couldn't work out was how to use the 2.0 tfsi coils in the existing head without remanufacturing the head cover. Loom wiring isn't an issue and it'll be nice to loose the POS's, but before I start travelling down that road I want to be clear what I'm letting myself in for.

Did read about knock sensors pulling back ignition advance if they spot pinking, was wondering if they fail to same occurs.


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