ABY ECU Intermittent issue

[UrS4boy]

.....in the picture you can see the valve with the exit towards the camera going to the hose between the turbo and the intercooler,

Hard to confirm/deny anything from that photo (sorry) but I can tell you straight up NO WGFV HOSE GOES TO ANYTHING [blinking red sirens]*AFTER*[/blinking red sirens] THE TURBO, i.e. NOT to the hose between the turbo and the intercooler.

[edge_devil]

The turbo hose that came off the original car had a small hose for the WGFV just after egress from the turbo, before the intercooler, I just remade that with the silicon pipes above....


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[edge_devil]

Just to clarify... One side of the WGFV is pressurised from the turbo, one side is in the intact tract before the turbo, and one goes to the wastegate. What I hadn't seen during installation was a takeoff on the turbo itself, just in the hose after the turbo...


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[twoqu]

Yes but the ports need to be oriented correctly or it will not function as Audi intended.
Shouldn't be too difficult to check/rectify if necessary.
We are basically trying to find anything that isn't as it should be in a factory install.

[edge_devil]

So as I understand it, the ONLY indicator on the N75 is one of the two opposing pipes is longer than the other one, and this longer one goes to turbo out(boosted) air, the opposite side to the wastegate and the lower one to the inlet tract between maf and turbo.


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[UrS4boy]

...We are basically trying to find anything that isn't as it should be in a factory install.

Agree. An unlabeled photo of a Medusa-head of purple hoses doesn't help us to help Mr. Devil.

[twoqu]

Nope!
The long one on the side goes into what we would call the MAF to turbo hose which essentially is vacuum. On the OE hose it is pushed into a small bore opening which of course you don't have.
The one opposite it goes to the lower port of the wastegate.
The one on the bottom goes usually to the nipple fitting on the turbo compressor which is essentially pressure.
Dave has provided a link with enough information to allow ID and orientation.

[edge_devil]

Sorry don't have my laptop to hand to label the picture....but all clear which goes where....now to test!!! ...and I'll provide a labelled diagram later, but photos of the new setup may be harder as the bodyshell is now on


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[edge_devil]

Hi my name is Tim and I'm a village idiot....its been two days since I did something really stoopid!!!



...yep that's the nipple with nuffing on it! Now fixed and I removed the N75 and connected it back up according to the diagrams. Hopefully a quick run at lunch time with the N75 disconnected from the ecu I should see a difference!

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[edge_devil]

Yay, idiot removed from the equation......

With N75 disconnected I am now getting a reliable .04-0.45 of boost, so that is a big Plus. I drove out with the N75 disconnected, stopped, reconnected it, switched off the battery for a minute and then drove back. This still only went to 0.4-0.5 boost, what would I expect from a normal engine?

I'll do the tests later that let the ECU switch the N75 on/off so I can confirm that is working, but I had done that a week or two back so I'm expecting that is all fine.

[twoqu]

Should be nearer 1bar!
Best to check for codes though first just in case. If no codes are shown and you are only getting that level of boost its possible if you are on ABY SW that the MFTS has an overheat signal which limits boost but does not throw a code. The SW is important as on the AAN this function is not used. I think we ID the modified SW as AAN based due to the 4A0 ID.
If you have the MFTS connected up (the large brass thing in the water rail on the cylinder head) you can try and disconnect it and see if full boost is restored.

[edge_devil]

We've now got stock ABY code in thanks to you Robin, but I can try the MFTS as you say.

Still no fault codes from the box, just checked... the hunt continues!

[edge_devil]

ABY ECU Intermittent issue

Just thinks btw, I can try the mfts, but also I can drop the Nero chips back in and see if they develop more boost as they are adu code and not reliant on the mfts...

Glad I made the ecu more accessible!


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[twoqu]

But that circumvents the idea of trouble shooting in a stock config! Of course its up to you. Its safer to use stock until you are certain everything is as it should be. I guess you are only using the MFTS for the ecu anyway so if its faulty you can just leave it disconnected if the theory holds up.

[edge_devil]

Your logic is sound

...so the temp sender on the back of the head is the only one used...but is the MFTS only used for the dash?

I'm using my separate dash and temp sender so if that's all no issue!