Boost Cutting

[Sonic]

Got the classic boost cutting with overboost protection... again...

Sometimes i can drive the car for a few minutes at full pelt, but eventually it gets to the point where anything above .5 bar at WOT causes it to boost cut.

Not using WOT or putting into valet mode with the switchable ECU lets me drive fine.

The car battery recently ran down, since then the idle has been awful on startup, flicking up and down between 500pm and 1500rpm on the rev gauge, and up and down on the boost gauge. Not sure if this is the same issue.

I've reconnected the N75 and checked lots of vacuum pipes to no avail.

VAG-COM tells me the following:

5 Faults Found:

00561 - Mixture Adaptation

13-00 - Adaptation Limit (Mul) Not Reached

00544 - Shareware Version. To Decode all DTCs

27-10 - Please Register/Activate - Intermittent

00537 - Shareware Version. To Decode all DTCs

08-10 - Please Register/Activate - Intermittent

01262 - Solenoid Valve for Boost Pressure Control (N75)

31-10 - Open or Short to Ground - Intermittent

00513 - Shareware Version. To Decode all DTCs

03-00 - Please Register/Activate


I've ordered a boost pressure test kit from Andy, so will see where i get with that. But can i just disconnect the MAF and go for a drive to test that?

Cheers

[A80Avant]

you may be having a N75 problem there. Have a look at it to see if it is broken or something causing a boost leak.

I think i may have a spare somewhere..

[Le S2 Audi]

Have you tried to reset the ECU by pulling the fuse's???

[Sonic]

I removed the ECU including the big connector and reconnected the vacuum pipe, making sure it wasn't bent over itself.

Should could as resetting the ECU

[BRY]

Have you tried a different battery?

[Le S2 Audi]

I removed the ECU including the big connector and reconnected the vacuum pipe, making sure it wasn't bent over itself.

Should could as resetting the ECU

Did you get the errors before or after unplugging it?

I would just pull the fuses (I assume you know which ones to pull... Big Twin One With Motuer On the Top...) and as Bry says try another battery...

[s2_wot]

@ Sonic, for what it's worth I had the following sequence of failures and the horrible idle sounds familiar to me..
Boost Leaks causing that cut in power. Then failure of the temp sender on the coolant rail and failure of the relay that controls the after run pump which I think killed battery #1.

Battery #2 went because of a knackered alternator. Before the alternator finally gave up the idle engine speed was horrible. It was like she was just limping along. I also blame a dodgy cd changer on killing off the battery.

HTH somehow

Shane

[Rusty]

I've had issues this week since a battery run down the other day

Idle was awful and it was running lumpy at times but was like a scalded cat at WOT.

I then realised that I'd swapped the MAF when I went back to my airbox (from cone filter) so had a look at it... the MAF in there was filthy! Have put my spare clean MAF on so see how that goes while I clean this one up. Otherwise I might have knocked something like a plug or wire... ah well

[newsh]

Maf connector or boost leak.

[Rusty]

Cleaned the MAF and all is well, it was really bad - I can only guess that the volcanic ash has made the job of the air filter especially difficult...

[europeanme]

thats scary, as I was going to post about a running issue....over boost cutting in....really bad idle speed...but my voltmeter is reading 14 or very slightly under so i would be amazed if my battery is on it's way out....

I will watch this post with great interest...

Mike

[Orion]

And I've got the same problem too 4000rpm fuel/boost cut off Car's in the garage today getting fixed

[s2_bo]

Good luck Andy,
If you want to try a new N75 let me know. I have 2 left.

Its prob also worth cleaning the maf like Andy said.

[newsh]

http://www.s2forum.com/forum/showthread.php?t=24544

[Sonic]

Good luck Andy,
If you want to try a new N75 let me know. I have 2 left.

Its prob also worth cleaning the maf like Andy said.

Cheers Bo, how much?

My plan is to clean the MAF, pressure test for boost leaks and try a replacement WGFW.