Low boost, high fuel consumption and 00561 fault

[LitD]

Hi all,

What do you reckon the following symptoms could be caused by? my urS4 has low/no boost, high fuel consumption (roughly 21mpg combined) and it was reporting an intermittant 00561 fault code. When the fault was cleared it got some boost back, but not all of it. I've taken the hose from the MAF off and the MAF itself looks ok, but there is some oil in the hose.

Other things that may be related, or may not are: erratic idle when cold, but stable once it's warmed up, some hesitation on gear changes. It pulls ok from low revs and doesn't cut out and it feels like it's running smoothly, just down on power.

Any guesses anyone?

Thanks

Rob

[UrS4boy]

Hi all, What do you reckon the following symptoms could be caused by? my urS4 has low/no boost, high fuel consumption (roughly 21mpg combined) and it was reporting an intermittant 00561 fault code. When the fault was cleared it got some boost back, but not all of it. I've taken the hose from the MAF off and the MAF itself looks ok, but there is some oil in the hose. Other things that may be related, or may not are: erratic idle when cold, but stable once it's warmed up, some hesitation on gear changes. It pulls ok from low revs and doesn't cut out and it feels like it's running smoothly, just down on power. Any guesses anyone? Thanks
Rob

•2413 (Blink Fault Code), 00561 VAG1551/2 Fault Code Number
Mixture Adjustment,
Adaptation limit exceeded, Adaptation limit not reached, Leakage in exhaust system before 3 Way catalytic converters, Incorrect signal for Mass Air Flow Sensor, Spark plugs, ignition coil(s), or Ignition Coil Power output stage malfunctioning
Symptom: Rich mixture, increased fuel consumption

You might want to clean the MAF inside and check and clean the connectors:

http://forums.quattroworld.com/s4s6/msgs/20442.phtml

Which, for future reference, was accessed by click on the MAF label in the lower right corner of this diagram (all the labels are live links to UrS info):

http://members.shaw.ca/speedtek/UrS%20Engine%20Bay%20Device%20Map.html

[LitD]

Cheers for that, I knew there'd be more info out there, but finding it is difficult. I saw a post about giving the MAF a bath in Isopropyl alcohol so I'll try that and get back to you.

[UrS4boy]

Cheers for that, I knew there'd be more info out there, but finding it is difficult.

Not if you bookmark and use this hot-linked 20VT Engine Device Map diagram:

http://members.shaw.ca/speedtek/UrS%20Engine%20Bay%20Device%20Map.html

[prj]

Leave the MAF alone, you are more likely to break it than accomplish anything by "cleaning it".

Start with a boost leak test. Measure your fuel pressure, make sure your O2 sensor is working, post a log from group 000 on hot idle.

99% sure you have a massive boost leak.

[bilko0795]

Rob as said when we plugged vagcom in i said then it was prob a boost leak as i had the same problem and have had the same advice from Prj did a test and now seems to be ok boosting to 0.7 on the boost gauge i have just fitted.

[UrS4boy]

The last time we played the 00561 game

Any guesses anyone?Thanks Rob

Rob: Before we start having the same arguements, er, discussion, you might want to read through this 00561 thread.

http://www.s2forum.com/forum/showthread.php?t=64262&highlight=boost+leak+testing&page=1

[UrS4boy]

S2 3B and ABY and RS2 ADU Boost Leak Testing

Leave the MAF alone, you are more likely to break it than accomplish anything by "cleaning it". Start with a boost leak test. Measure your fuel pressure, make sure your O2 sensor is working, post a log from group 000 on hot idle.
99% sure you have a massive boost leak.

While I disagree about NOT checking and cleaning the MAF (e.g. with isopropyl alcohol (IPA)), checking for boost leaks is definitely a good idea.

Rob: Here is a post showing your boost testing options and some of the places that are the most likely suspects for a leak:

http://www.s2forum.com/forum/showthread.php?t=63974&highlight=boost+leak+testing

[stocious]

Maybe give the maf plug a wiggle/clean.

[AndyP]

You're also in for a shock if you think 21mpg is high

[LitD]

Ok, assuming a boost leak for a min, can you use an ABY boost test kit on an AAN? And cross-check with Bilko, that was an ABY kit you had wasn't it?

Thanks all

Rob

[UrS4boy]

AAN Boost Leak Testing Options

Ok, assuming a boost leak for a min, can you use an ABY boost test kit on an AAN? And cross-check with Bilko, that was an ABY kit you had wasn't it? Thanks all Rob

Rob: Sorry, I totally forgot that the patient is an UrS4 (like mine). Here is the link to the AAN version of my boost leak testing options post. The testers will be the same as the ABY ones.

http://www.s2forum.com/forum/showthread.php?t=63987&highlight=AAN+boost+leak+testing

[LitD]

Well I went out and painted as much as I could reach with soapy water and I didn't get any froth, certainly not off the michelin man pipe. There is a ticking at the back of the engine bay thoug, no idea if this is related. Thanks for all the help guys, at least I can start crossing stuff off the list.

[prj]

Which parts of the inlet tract did you pressurize?
How long did it take to drop from 0.5 bar to zero once you stopped putting air in?

[LitD]

I didn't do a full boost test with the kit, I just wiped all the boost hoses that I could reach with a soapy cloth then ran the car, on the basis that anything leaking would show up with bubbles.