Low boost, high fuel consumption and 00561 fault

[prj]

MAP sensor has no effect on fuelling.

[dodger]

This has nothing to do with your problem. Wishful thinking on your part here.
If the chip was loose enough to not give contact the engine would instantly shut down. There's no "running a little worse because a chip was a little loose" it's just not how it works in the computer world where all is binary.

What you did by removing the ECU and removing the power from it was reset the fuel trims. Don't worry, it will probably learn back to the same state after a while, because you did not fix the underlying problem. After the fuel trims learn far enough, you will also get the same lambda code.

I understand.

Forgot to mention I changed chips to another ECU as well, maybe there was a problem with the other ECU/ map sensor?
I have earlier removed the power from the car.

Please answer my PM

[prj]

This has nothing to do with your problem. Wishful thinking on your part here.
If the chip was loose enough to not give contact the engine would instantly shut down. There's no "running a little worse because a chip was a little loose" it's just not how it works in the computer world where all is binary.

What you did by removing the ECU and removing the power from it was reset the fuel trims. Don't worry, it will probably learn back to the same state after a while, because you did not fix the underlying problem. After the fuel trims learn far enough, you will also get the same lambda code.

[UrS4boy]

..Could have saved me alot of troubleshooting and frustration if I had just looked inside the ECU first, but then again, I've learnt a lot and have some new parts for the engine .

"Sometimes the simplest solutions are the hardest to find"

From my end, your situation made me photograph the G61 and G66 knock sensor connectors and find a wiring diagram for my Knock Sensor post. So not all lost here either.

[dodger]

Thanks for your replies

Think I finally solved the problem today Pulled out the ECU to try another one.

Opened it and saw the fuel chip had loosened from the socket on one side. Pushed it down where it's supposed to be and test drived.

Engine pulled much better without hesitation and no more fault codes

Could have saved me alot of troubleshooting and frustration if I had just looked inside the ECU first, but then again, I've learnt a lot and have some new parts for the engine

I hope the amount of air coming from the PVC is normal. Below 0,5 bar it holds pressure quite a while. But maybe I should do a leak down test just to be sure.

[prj]

If you have so much air coming from the PCV that you can't build and hold pressure without it then either:
a) Your turbo oil seals are shot
b) Your engine is worn (rings)

Try pressurizing post-turbo, if the problem does not clear and you are 100% sure that everything is connected correctly, then do a leakdown test and possibly rebuild the engine.

[UrS4boy]

G61/G66 Knock Sensor Information

Based on this thread, I just added the info below to my G61/G66 Knock sensor info post. The wiring colours are based on the AAN. (Sorry ) Not sure how well they apply to the ABY and ADU:

First the AAN wiring diagram:



Then confirmation of the wire colours at the harness connectors:

G61 (Front, Green):



G66 (Rear, Blue):



Might come in handy during an issue diagnosis in the future? (or right now, as the case may be)

More G61/G66 info, with the updates, here: http://forums.quattroworld.com/s4s6/msgs/21047.phtml

[UrS4boy]

Have been struggeling some time with these fault codes. And I have been searching for boost leaks over and over.
00537 - Lambda (Oxygen Sensor) Regulation
11-10 - Control Limit Not Reached - Intermittent
00540 - Knock Sensor 2 (G66)
03-10 - No Signal - Intermittent
AFR = 10,5 @ WOT, should be 11,5
Hesitates and generates codes when WOT and sometimes limp mode. Plugs sooted.
Think I will change the knock sensor #2, behind the cruise controle thing. Someone knows if I can measure the sensor with multimeter?

Starting with the last question: From the C4 UrS Robert Bentley manual, pg. J28-27:

"The knock sensors cannot be checked electrically. Check DTC memory => Repair Group 01. For satisfactory function of the knock sensors, exact compliance with the tightening torque of 20 Nm (15 lb ft) is important. Check the harness connection from knock sensor to wiring harness for corrosion".

I think the last bit is critical, i.e. check your knock sensor connectors. These are the green and blue connectors on the connector rack.

Knock sensor info: http://forums.quattroworld.com/s4s6/msgs/21047.phtml

O2 (Lambda) sensor "control limit not reached" on these cars typically means that air that the MAF told the ECU went through (so the ECU can adjust the fueling) went missing between the MAF and the engine (and hence the O2 sensor). The O2 sensor-ECU feedback loop is used to try to adjust things but there is enough air leakage that the ECU is unable to adjust the fuel downwards enough, i.e. low air fuel ratio = rich running = sooty plugs. So definitely a boost leak. Have you checked the intercooler pipe O-rings, etc for leaks. Are you even using a spray bottle with soapy water sprayed on the usual (and unusual) suspects?

[dodger]

Yes, but I mean when having a bung in the MAF to turbo hose and then taking off and blocking the return line from PVC on the MAF hose, leaving the pipe from the cam cover ventilated, like Prj explained earlier in the thread. How much air should escape from the PVC system(pipe from cam cover) when intake system is pressured to 15psi?
On my AAN, there is some air coming from the PVC. It doesn't take long to build pressure if I block with my hand. So I changed the one way bleeder valve under the intake. But the valve seemed fine, and no change. But I suspect it's working as designed. Pressurre holds for quite some time, when below 8 psi.

Have been struggeling some time with these fault codes. And I have been searching for boost leaks over and over.

00537 - Lambda (Oxygen Sensor) Regulation
11-10 - Control Limit Not Reached - Intermittent

00540 - Knock Sensor 2 (G66)
03-10 - No Signal - Intermittent

Changed/cheked

MAF
O2 sensor
N75
diverter valve
updated coils
Injectors
Fuel pump
AFR = 10,5 @ WOT, should be 11,5

Hesitates and generates codes when WOT and sometimes limp mode. Plugs sooted.

Think I will change the knock sensor #2, behind the cruise controle thing. Someone knows if I can measure the sensor with multimeter?

[K Simmonds]

I wouldn't pressurize the PCV system with 15 PSI, 6 or 7 is more than enough and your well advised to stay below 5.

A super cheap pressure test bung can be made from an empty tin of beans and a tyre valve, the PCV system can be blocked with a big bolt, it really is that simple.

[dodger]

How much shall the PVC system vent to atmosphere when pressured to 15psi?

[mcandmar]

Get a Schrader valve from your local tyre shop. Then buy a new oil filter that fits inside your MAF hose. Drill a hole in the end of the filter, pop in the valve and hey presto a ghetto boost leak tester.

I like it, but not as ghetto as this idea

[5cylinderman]

Get a Schrader valve from your local tyre shop. Then buy a new oil filter that fits inside your MAF hose. Drill a hole in the end of the filter, pop in the valve and hey presto a ghetto boost leak tester.

[UrS4boy]

You an make your own pressure tester using a pipe bung and car valve.

Something like this (this one has an air compressure hose connection but it could be a tire Schraeder valve instead).

[Rusty]

^^ ^^

You an make your own pressure tester using a pipe bung and car valve.