Need an opinion on my boost problem....

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Oct 9, 2005 | 06:28 PM

afaudi07

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Need an opinion on my boost problem....

So I have changed my MAF, DV, all vac lines, N75 and even my boost gauge to see if they are the problem. I am an 01 1.8 with an X chip and 67k miles.

Here's the deal: the car doesn't feel nearly as strong as it used to. It will boost up to 15-16 psi and it will drop to ten at 5k rpms. No CEL and I don't have a mobile vag to run logs.

After searching I found Silver Streakin having similar issues with a bad wastegate. Any opinions are greatly appreciated. Thanks!

Oct 9, 2005 | 07:10 PM

Audi2ptzero

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Are the outside temps much lower now then they were before?

Oct 9, 2005 | 08:01 PM

afaudi07

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About 20 deg lower, right around 60-65.

Oct 9, 2005 | 08:08 PM

Audi2ptzero

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Well that is most likely the reason for the lower boost readings.

Colder air will cause lower readings in the manifold because of the denser air and the engine will produce more vac.

Oct 9, 2005 | 08:28 PM

afaudi07

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15 spike with 13 hold on an X chip?

I realize the cold air makes a large difference but I ran my APR chip last winter that held 17-18 psi no sweat. BTW, thanks for the input, this process ahs been frustrating

Oct 9, 2005 | 08:33 PM

afaudi07

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guess I was a little unclear in the first description...

I was in the process of swapping gauges and didnt have one on it over the summer. At the end of August, I was spiking 17, holding 14. My vacuum is now 18 inHG at idle, 20 while coasting in gear.

Oct 9, 2005 | 10:00 PM

Kolt45

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Seems low...Have you done a pressure test?

I found a leak in the Suction Jet pump (#11). Here's my old post with the vac diagram. Just a thought...

https://forums.audiworld.com/a4/msgs/2373430.phtml