Idle pauses. After catbypass pipe install. Air Bag Light??

[ProjectM96]

Hey. I just installed secondary bypass pipes with new gaskets and bolts yesterday.

When I rev to any rpm. Lets say 3000rpm. And I let go of the gas. It stays at 3000rpm for an additional second before goes back down to idle speed.

When revving passed 4000 rpm, I hear a whistling type of noise from the exhaust. Are they related?

Any idea what could be causing these?

Everything seems tight except where the bypass pipes meet the U pipe connecting it to the Muffler.

The bypass pipe is inserted into the U Pipe and it is a tight fit I cannot move with my hands, but the bolts for the clamps on the U pipe are not currently installed. So exhaust gases could potentially leak from there. That is my best guess for now.

Last thing, My air bag light randomly lit up for 3 seconds, then shut off, then back on, then off. This was about 1 hour after driving for the first time with bypass pipes. Don't know if it is related or what it could mean.

Thanks.

[Burg Boxster]

Airbag light should not go on/off. Once it trips it should stay illuminated until [code read and] reset by Durametric, PSTII or PIWIS - as I understand how the systems work. Might it have been a CEL which is probable considering O2 sensors and cat bypass (which require a spacer correct?)?

The 3000 studder sounds like relearning of ECU. Should be fine w/ ~ 50 miles or so.

Whistling definitely points to a leak somewhere in system. A quick test, if you have some handy, is to put some exhaust heat wrap on the connection. Though it feels tight by hand, once under load the whole system flexes a fair amount and at 4000 you're getting into the power band.

Good luck

[ProjectM96]

No it is the air bag light. No CEL on.

I just read on 986faq.com that it is a common problem associated with the air bag sensor in the belt buckle and there is a Porsche technical bulletin for it.

As for the Exhaust. I have the 2.7 Boxster. There is no O2 sensor in the mid pipe and it does not cause CEL or emission testing problems.

I found the problem. I turned on the car and put my hand around the connections. Exhaust gases were leaking out of two places where I did not have the bolts installed. So I am buying bolts tmrw from Home Depot and tightening it. That should fix everything.

I drove about 60 miles this morning for the first time after installing them before the ECU re-learned as you say. And after I drove it again for 5 miles a few hours ago at night, the idle pause was suddenly gone and seems back to normal. For now.