Interesting boost issue

[JustManson]

Hello everyone.

I have a newly acquired 2000 S4 with a stage 3 GIAC tune.

I find that when I first turn the car on I can achieve up to 20 psi of boost. It's amazing btw!

My issue is after about 30-45 minutes of driving say highway when I get back on to regular streets my boost reduces down to 7psi.

I have no logs, I have no application to do that. I also dont have a code reader yet... working on that. I do have a check engine light and the prior owner said it was an o2 code which I haven't resolved yet.

Any ideas? I simply just want to resolve that issue, but don't know where to start.

Did I mention this is my first Audi?

Thanks!


Sent from my iPhone using Audizine

[Speed4Avant]

Hello everyone.

I have a newly acquired 2000 S4 with a stage 3 GIAC tune.

I find that when I first turn the car on I can achieve up to 20 psi of boost. It's amazing btw!

My issue is after about 30-45 minutes of driving say highway when I get back on to regular streets my boost reduces down to 7psi.

I have no logs, I have no application to do that. I also dont have a code reader yet... working on that. I do have a check engine light and the prior owner said it was an o2 code which I haven't resolved yet.

Any ideas? I simply just want to resolve that issue, but don't know where to start.

Did I mention this is my first Audi?

Thanks!


Sent from my iPhone using Audizine

you're going into limp mode when it's only hitting 7psi: could be a combination of things, o2 sensors, boost leak, etc. I'd get a vagcom cable or scan your codes at a parts store.

[getslideways]

Sounds like limp mode. Its the cars way of protecting itself when it sees something it doesnt like. Keep in mind not all codes trigger the Check Engine Light. Get a generic VAGCOM tool and use VDS lite if you are on a budget. VAGCOM is invaluable for B5 ownership.

[JustManson]

Ok. Thank you both for your replies. I have the dummy cable and will download the Vagtech this weekend. I figured it was limp mode.... this helps confirm what I need to get to diagnose further.

Prior owner specified and supplied an O2 sensor so maybe that is it.

If I turn off and turn on the car it goes back to "normal".








Sent from my iPhone using Audizine

[MacDaddy]

$12 ebay k line adapter and VCDS shareware will give you code reading and some reprogramming ability

[JustManson]

Thanks Mac.


Sent from my iPhone using Audizine