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rs4 bad idle / power

Posted: Tue Oct 02, 2007 7:28 am
by MK
Hello!
I'm new to here and have some problems.
When I bought the car , everything seemed allright only I could tell that there is something wrong with the power output (i.e. My last car - Audi S4 2.2T with GT3071 ran better)

Last week the car started to stutter when I push fast on the accelerator (cuts the power somehow), I was hard to start driving because sometimes it just shuts off because of this stuttering, at WOT the car stutters, too. I thought this is somehow related to the fuel delivery so checked the injectors/fuel pump and everything was all right. I changed the fuel filter but nothing changes.
Then I unplugged the MAF and everything working flawlesly, only many of the lights on the tacho came on (limp mode?)

Then one of my friends connected the car to the VAG-COM and the outputs were bad maf and this:

16490 - Manifold / Barometric Pressure Sensor (G71) / (F96): Implausible Signal

I changed the MAF to new one/ reconnected the battery and everything worked flawlesly yesterday - only few hours :cry:
Now it has the same stuttering as before.

My friend said that G71 sensor ir located in the ECU and therfore can't be changed just purchasing the sensor (located on the ECU board)

Also, He told that this could be related to the bad software change in the ECU (I thought that the car is OEM w/o aftermarket software). Also I searched www.audiworld.com forum and the 16490 can be related to the bad EPROM connection.....

Do I need to find a new ECU ?

I have had no opportunity to check the car for boost leaks, but are there really any regularities between the boost leak and the 16490 / G71 error and stuttering?

Thanks for any advice in advance!

RE: rs4 bad idle / power

Posted: Tue Oct 02, 2007 10:17 am
by Contigo
Where are you based?

Get the car to MRC if you are within a couple of hours of Banbury and let Doug give it a healthcheck. He will pressure test the system and check for Boost leak, bad DV's and full VAG code checks. Only 50 notes and well worth it. Mine had bad DV's and a boost leak and it's running so much better now.

Posted: Tue Oct 02, 2007 10:18 am
by TopBear
Hi MK, looks like we have similar issues. See my post here http://www.rs246.com/index.php?name=PNp ... ic&t=64633

I have ordered a new MAP (G31) sensor to see if this cures it, should arrive today or tommorow so will know if does.

Re: rs4 bad idle / power

Posted: Tue Oct 02, 2007 11:54 am
by MK
I wish I could drive to MRC ... it's a bit far away ... 2-3 thousand km's ? :)
I could only try to ask for a help here .....

Posted: Tue Oct 02, 2007 11:55 am
by MK
TopBear wrote:Hi MK, looks like we have similar issues. See my post here http://www.rs246.com/index.php?name=PNp ... ic&t=64633

I have ordered a new MAP (G31) sensor to see if this cures it, should arrive today or tommorow so will know if does.
I got the MAP error, too, but after reconnecting it , the message disapeared.

Posted: Tue Oct 02, 2007 5:34 pm
by TopBear
new MAP sensor fitted and its all working 100% again.

Both DTC codes now gone, after a couple of scans to check.

Have you done another VAG-COM scan?

Posted: Tue Oct 02, 2007 10:25 pm
by MK
Can anyone tell me please - what is the difference between the MAP sensor and Barometric sensor (G71)? Can these be the same things ?????

Posted: Tue Oct 02, 2007 11:27 pm
by TopBear
My view is that the MAP sensor G31 is the 'Manifold' part of the Manifold / Barometric Pressure Sensor (G71) / (F96) error code.

So a faulty MAP sensor G31 not signalling correctly to the ECU F96 sensor could cause the 16490 error code.

Just my interpretation as the new MAP sensor fixed both codes for me.

Posted: Sat Oct 06, 2007 4:41 pm
by MK
Thanks, TopBear! Power is back changing the MAP for me , too ! :) :) :)

Posted: Sun Oct 07, 2007 2:21 am
by TopBear
MK wrote:Thanks, TopBear! Power is back changing the MAP for me , too ! :) :) :)
Nice one :D