RS2- Just had a dyno run...power down (any thoughts?)

[AndyP]

Just use some araldite ( or similar ) to seal it up, that's what I did. You'd also be suprised how such a small leak can effect the running of the car.

[prj]

The first test was pointless as the intake was blocked off, it shows nothing.
Bubbling is normal.

About 2nd test:
1. By removing maf->turbo hose which actually should hold air to 14 psi easily, it is not fully valid.
2. The N75 and it's lines were not tested.
3. The breather system should only be unplugged at the front, not below the manifold (if that was done) as there is a check valve there and it is important this check valve gets tested.
4. There were no details about this test. How much air was put in, how quickly it dropped.

Every single one of these cars can be tested by the test I described through maf->turbo hose. Yours can't. Why does your MAF->Turbo hose not hold 1 bar of pressure? Yes this is not a pressure leak, but this is different to all other cars.

[A80Avant]

When I did tests I had acquired multiple bungs and i took all hoses out and tested them individually as much as possible. That left out the injector seals which is an easy replacement anyway. That's just another thought

[prj]

The reason for the low boost pressure is not a small leak from the ISV.

If indeed a leak test is done correctly at least once and confirmed that it is leak free, it is either the altitude sensor being bad, IAT or something in relation to boost control not working correctly.

The spring in the stock configuration is very soft, and thus boost is extremely precisely controllable. To modify the boost pressure a fairly large change needs to happen to the N75 duty cycle.
The stock PID is thus very aggressive, and if it can not reach desired set point, it will quickly drive the the PWM of the N75 to 100%.
It will also remember the actual required duty cycle for a bunch of RPM ranges and do it over and over and over again as soon as it misses the full boost the first time - adaptive boost control.

So the question is rather - is the ECU not requesting boost, or is the ECU not being able to meet boost request. This is the main question that needs to be answered.

[newsh]

If the MAF hose doesn't seal to the turbo then there will be a vacuum leak which will draw in unmetered air and cause a lean condition which the ECU will try to adapt to. I wonder though if the MAF hose will not pressurise because of a leak in the PCV (breather) pipes, the DV, or the N75 pipes. Is the DV in good condition and it it operating correctly? Have you driven the car with the N75 disconnected to see if the boost drops to normal spring pressure?

[weta.worker]

PRJ and my mechanic have each others details so hopefully it'll fast track some fixing

Thanks SOOOO much PRJ (Dmitri!)

Cheers!

John

[weta.worker]

hiya, a bit of a while since the last update.

In March PJR and the mechanics found after all the boost leak tests the car wasn't requesting more boost so thoughts are something up with the ECU.

PJR was going to source a replacement to swap in which was great. No rush, so just emailed him every month as a friendly reminder.

Haven't heard from him in a while but realise he's done me a huge favour talking to this end and helping diagnose a possible issue.

Hopefully he'll resurface soon and we can get a ECU to ship over here to plug in.

I've been looking at other options (it's been a few months with no reply) and have opened up my current ECU and taken photos for tuners at this end.

Here are the pics if anyone is interested.

I've noted that the hose that runs into the ECU starts off nice and thick (green) , then goes into the cloth \ braided one, then into a really thin black one, then back to the cloth?



















under the above plastic cover



and under the other one



Hope all is well Dmitir.

Cheers!

John

[Laaf]

You have the wrong MAP sensor fitted. RS2s should have 300 kPA installed from factory, but you have got a 250 kPA.

[Rusty]

When you day it's not requesting more boost, what is it running? If it's 0.4 bar then you note than likely have a knackered MFTS. Unplug it to test if it boost properly.

[220bhp]

Looks like someone has changed ether the map sensor or the ecu at some point.
The other possibility is the timing/ RS2 is one tooth out on the cam belt.

[sailaz]

http://i603.photobucket.com/albums/tt111/wetaworker/Audi%201994%20RS2%20GUARDS%20RED/132F6F91-4C4F-4EC4-AD8F-A5A7F70B9E9B_zpsqi4y1hwu.jpg

photo of the sticker on ECU availible ?

[K Simmonds]

I suspect that's an ABY ECU which would probably explain your issues, as above we need the part No of the ECU itself in order to ID it. The ECU also appears to be socketed and I'm not sure the boost/motor chips look factory, I don't have enough experience to say either way, Dimitri would tell you in an instant if they look original or not.

[Rusty]

The files for stock RS2 chips are available on here.

Best thing to do might be to buy or borrow a converted ABY-RS2 ECU and give it a whirl.

My ECU was converted by hoffer76, although I'm not sure if he does this any more. I'm sure that prj can point you in the right direction...

[veneto rs2]

On my RS2 (and all i have seen so far) the green line goes into the braided/cloth and then directly into the ECU pipe.
That said....

As far as I can see seems from the pics that the # of the ECU could be a 8A0907551 B which will put it right on the RS2 part that according to KATE could be either:
8A0907551 B or 8A0997551 C

S2 ABY still according to KATE should be 895907551 A for an S2 Avant

[weta.worker]

On my RS2 (and all i have seen so far) the green line goes into the braided/cloth and then directly into the ECU pipe.
That said....

As far as I can see seems from the pics that the # of the ECU could be a 8A0907551 B which will put it right on the RS2 part that according to KATE could be either:
8A0907551 B or 8A0997551 C

S2 ABY still according to KATE should be 895907551 A for an S2 Avant

Pic of ECU





Apparently the B version is without immobiliser and C is with.