Carpokes

So my car started making a rattling sound similar to an exhaust leak. Upon careful inspection, I found this to be the culprit:
This tube which is on the passenger side of engine near the firewall had broken loose (looks to have rusted loose). I've seen it in the past (while it was attached), but have no idea what its purpose is. Anyone?

Thanks,
Ken

This is/was for early emissions testing, specifically for inserting a probe to measure the carbon monoxide content in the exhaust, to aid in setting the idle mixture. In a few models which have non adjustable idle mixture, like the 944 S, S2, 968, and possibly some of the turbos, its only purpose was for checking the CO content to determine if the motronic engine management was correctly setting the mixture. Sadly, unless you have a way to measure CO content it's not going to be useful to you.

It was a diagnostic port to check exhaust gases. You don't really need it unless you are looking to measure back pressure. You need to do something to address the broken one, however, as you now have a sizeable exhaust leak in front of the turbo (which will rob you of power). If you get under the car, you can see where it connects on top of the cross-over pipe. Undo the nut holding it in place, and you can remove the remainder of the pipe. Then be sure to cap off the port to prevent an even bigger exhaust leak. A 944 lug nut works perfectly as a cap.

We kind of thought it had something to do with emissions. I had my mechanic weld a cap on top of the hole and that quieted down the noise. I just wanted to make sure it wasn't something more important. Thanks!

motoken wrote: Fri Jul 18, 2025 6:47 pm We kind of thought it had something to do with emissions. I had my mechanic weld a cap on top of the hole and that quieted down the noise. I just wanted to make sure it wasn't something more important. Thanks!

Welding it shut should take care of it. I have an exhaust gas temp sensor in that port, but most people would never need that port for anything.

So I took the car out for a spirited drive tonight, and on some accelerations, i would get a lot of rev but not much speed. Thoughts?
I am going to take a look under the car when it cools off to see if maybe the welded patch held or not.
Thanks,
Ken

Well, i took a close look at the weld, and it still looks good.

Could this be clutch related?

If the car is in gear and the engine revs without a proportional increase in speed, then either the clutch is spinning or the tires are.... A spinning clutch is generally pretty obvious, and usually starts in higher gears in lower to mid rpms -- when the clutch is under the most pressure -- like up a grade in 5th gear when you floor it... As it gets worse, it will start to slip in more and more situations.

Yeah. i think that is what is happening. I just replaced the slave and master clutch cylinders. Could something out of wack there be the culprit. The clutch pedal is significantly firmer than it was before the of those parts as well.

It had all the symptoms of a clutch lever that’s cracked and flexing. Did you replace the slave because of poor engagement?